PRIVATE APPLICATOR
TRAINING MANUAL
A HOME STUDY COURSE
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
-------
j3 ($b -J
ACKNOWLEDGMENTS
This manual was developed by the U.S. Environmental Protection Agency,
Region VIII, Denver, Colorado. Cooperative Extension Service publications of
the following universities were invaluable sources of information and
material: University of California, Colorado State University, University of
Illinois, Iowa State University, Montana State University, Michigan State
University, Ohio State University, Purdue University, and the University of
Wyoming. Publications of the United States Department of Agriculture and the
Wisconsin Department of Agriculture also provided excellent and extremely
useful information. Information contained in previously published EPA
documents was also used in developing this manual.
SEPTEMBER 1983
-------
INTRODUCTION
The amended Federal Insecticide, Fungicide and Rodenticide Act (FIFRA)
contains a number of provisions designed to improve the control of pesticide
use in terms of the environment and man while at the same time assuring that
pesticides can continue to be available.
The amended FIFRA requires the U.S. Environmental Protection Agency (EPA)
to classify all pesticide uses as either restricted use or general use. The
FIFRA further requires that only certified applicators or applicators under
the direct supervision of a certified applicator can apply pesticides
classified for restricted use.
A pesticide product is designated as restricted use by EPA when it is felt
that it may generally cause, without additional regulatory restrictions,
unreasonable adverse effects on the environment, including injury to the
applicator. Restricted use classification is an alternative to the
cancellation of certain pesticides. The certification program is designed to
ensure that users of restricted use pesticides are properly qualified to
handle and apply these materials in a safe and efficient manner.
There is an increasing awareness among the general public concerning
pesticides and problems associated with their use and misuse. Some of the
concern is justified, some perhaps is not. Few would deny that pesticides are
a vital tool for modern agriculture. Their continued use without further
regulation, however, depends on their proper use.
This manual is designed to help ensure that private pesticide applicators
use pesticides properly and that you, your neighbor and the environment are
adequately protected. It is meant for your, benefit and the benefit of
agriculture. Improper use by a few is enough to deny the present benefits of
pesticides to all.
This manual is not designed as an endorsement of pesticides. Indeed,
other methods of control and particularly the implementation of integrated
pest management (IPM) programs are strongly encouraged. Pesticides and their
use are, however, the main concern of this manual.
-------
This publication was prepared for private applicators who wish to be
certified or recertified to use pesticides classified for restricted use. The
information in this manual has been prepared to teach you:
1. Some facts about the various pests which may affect your farming
operation,
2. A variety of methods which can be used to control pests,
3. What to look for on the pesticide label,
4. How to use pesticides so they will not harm you or the environment,
5. How to choose, use and care for application equipment,
6. Some basic calibration procedures,
7. Economic considerations regarding pest control, and
8. The Federal Isms that apply to the use of pesticides.
Private applicators who successfully complete the questions accompanying
this manual will be eligible for certification as defined by the amended
FIFRA. This manual ma*y be used by commercial applicators as a study guide but
will not serve as a method for commercial applicator certification or
recertTFTcation.
-------
TABLE OF CONTENTS
Page
Chapter 1 Laws and Regulations 1
Chapter 2 Labels and Labeling 3
Chapter 3 Pesticide Safety 5
Chapter 4 Pesticides 18
Chapter 5 Pests 24
Chapter 6 Application Equipment and Calibration 56
Chapter 7 Application of Pesticides 69
Chapter 8 Pesticides and the Environment 76
Terms Used in Pest Control 83
-------
CHAPTER 1
LAWS AND REGULATIONS
__ The Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA) requires the U. S.
¦ I¦ ¦ M#% Environmental Protection Agency (EPA) to regulate
pesticides. The FIFRA provides that all pesticide
uses be classified for restricted use or general use. Pesticide products are
classified by £se and not necessarily by the active ingredient. A pesticide
me(y contain 5 percent of a certain active ingredient and be classified for
general use while another pesticide has 25 percent of the same active
ingredient and is classified for restricted use. Another example is that two
pesticides may contain the same percentage of the same active ingredient and
be classified differently. An example is when the restricted use product is
registered for use on irrigation ditch banks while the other product is for
agricultural crop land and is classified for general use.
In addition to requiring that all pesticide uses be classified for
restricted or general use, the FIFRA requires that only certified applicators
or applicators under the direct supervision of a certified applicator can
apply restricted use pesticides. There is an individual certification
program for each state. In most states the state department of agriculture is
conducting the program. However, there are some states in which EPA is
administering the program.
The FIFRA defines two types of pesticide applicators: private and
conmercial. A private applicator is a person who uses or supervises the use
of restricted use pesticides in the production of agricultural commodities on
land owned or rented by him or his employer. A private applicator can apply
restricted use pesticides on the property of another person if applied without
compensation other than the trading of personal services between the producers
of agricultural commodities. A commercial applicator is any person who uses
or supervises the use of restricted use pesticides and is not a private
applicator. Examples of commercial applicators include but are not limited
to: ditch company employees, golf course workers, grain elevator operators,
applicators employed by government agencies, and applicators who apply
pesticides for hire.
An applicator may apply a restricted use pesticide without being certified
if he is under the direct supervision of a certified applicator. "Under the
direct supervision of a certified applicator" is defined as follows: "Unless
otherwise prescribed by its labeling, a pesticide shall be considered to be
applied under the direct supervision of a certified applicator if it is
applied by a competent person acting under the instructions and control of a
certified applicator who is available if and when needed, even though such
certified applicator is not physically present at the time and place the
pesticide is applied". If a restricted use pesticide is applied by an
uncertified applicator under the direct supervision-of a certified applicator,
-------
- 2 -
both the actual applicator and the individual supervising the application are
legally responsible for its proper application. If a violation occurs, both
individuals could be subject to civil or criminal fines under the amended
FIFRA or various state pesticide laws.
EPA is also responsible for regulating the amount or residue of a
pesticide which can remain in or on raw farm products. EPA sets residue
tolerances under regulations authorized by the Federal Food, Drug and Cosmetic
Act. A tolerance is the concentration of a pesticide that is judged safe for
human consumption. Residues in processed foods are considered to be food
additives and are regulated as such.
Tolerances are expressed in parts per million (ppm). One ppm equals one
part (by weight) of pesticide for each million parts of farm or feed product.
Using pounds as a measure, 50 ppm would be 50 pounds of pesticides in 999,950
pounds of farm product. The total pounds of pesticides (50 lbs.) plus the
total pounds of farm product (999,950 lbs.) is one million pounds.
If too much residue is found in or on a farm or feed product, the product
may be seized or condemned. In order to help an applicator avoid an illegal
residue, pesticide labels provide instructions on proper application rates and
the number of days the pesticide m«y be applied prior to harvest. By reading
the pesticide label you can help prevent illegal residues and avoid possible
loss of your crop.
The FIFRA prohibits using a pesticide in a manner inconsistent with its
labeling, in other words "misusing" a pesticide. It is also illegal to
dispose of any pesticide container or pesticide rinsate by a means other than
those stated on the label; or to detach, alter, deface or destroy any part of
the labeling. However, the FIFRA permits applying pesticides at any dosage,
concentration or frequency less than that specified on the label. A pesticide
m«^y also be used to control any target pest not specified on the labeling if
the application is to the crop, animal or site specified on the labeling and
is not prohibited by the labeling. It is also not considered misuse to employ
any method of application not prohibited by the labeling or to apply a
pesticide in combination with another pesticide or fertilizer if such a
mixture is not prohibited by the labeling.
EPA may assess penalties for violations of the FIFRA. A private
applicator who violates any of the provisions of the FIFRA may be asessed a
civil penalty up to $1,000 for each offense. (EPA will send a private
applicator a warning letter for the first violation.) Criminal offenses
(knowing violations) can result in private applicators receiving a $1,000 fine
and/or 30 days in prison.
Commercial applicators can be assessed a $5,000 civil penalty for each
violation or a $25,000 fine and/or one year in prison for a criminal
violation. EPA is not required to send a commercial applicator a warning
letter prior to assessing a fine.
-------
- 3 -
CHAPTER 2
LABELS AND LABELING
There are two exhibits which will be" used for this chapter. Exhibit 1 is
a front panel of a sample label and Exhibit 2 is the back panel of a sample
label. Exhibits 1 and 2 are located at the end of this Chapter.
The printed material on a pesticide label and labeling (literature which
accompanies the product) has all of the necessary information and instructions
for the effective and safe use of the pesticide. The FIFRA requires each
pesticide label to include the following:
1. Brand name, common name, and chemical name,
2. Use classification,
3. Ingredient statement,
4. Registered uses,
5. Directions for use,
6. Safety information, signal words and precautions,
7. Net contents,
8. Name ana address of manufacturer or registrant,
9. EPA registration number and the establishment number.
The brand name is the producer's or formulator's proprietary name for the
pesticide. The common name is the generic name accepted for the active
ingredient of the pesticide product regardless of the brand name. The
chemical name of the pesticide is generally found in the ingredient statement
and lists the chemical for which the pesticide is designed.
Pesticides are classified for general use or restricted use and each
pesticide label should indicate the classification of that pesticide. Some
pesticides have not been classified and will not have a classification
statement on the label. However, all pesticides which have been classified
for restricted use must have the following statement on the label.
"For retail sale to and use only by certified applicators or persons under
their direct supervision and only for those uses covered by the certified
applicator's certification."
The pesticide label only lists the uses for which the pesticide is
registered. These are the legal uses for the product. It is illegal to use a
pesticide in a manner inconsistent with the label's registered uses. There
are a few exceptions which were discussed in Chapter 1.
The directions for use give specific instructions for using the product
properly and tell you when to use the pesticide, how to apply the particular
formulation, where to apply it and dosage rates. Directions for use also give
you information on the number of applications that can be made over a given
period of time and the length of time and days that you must allow between the
last application and harvest or slaughter.
-------
- 4 -
On some pesticide labels you will find a range for the suggested dosage.
For example, the label may suggest 1/2 to 2 pints of active ingredient per
acre. In this case you should use the lowest rate that will give the best
control. If you have questions or doubts, be sure to contact your local
county extension agent or agricultural consultant for suggested rates that
work best in your area.
The label contains the information you need to use the product safely.
Certain signal words are required on every pesticide label. Depending on the
hazard to the user of the particular product, these words are DANGER-POISON
and the skull and crossbones (all in red), WARNING or CAUTION. In addition,
the label must carry the statement KEEP OUT OF THE REACH OF CHILDREN. The
signal word required depends upon the toxicity and potential hazard of the
active ingredient and also the formulation of the pesticide. The following
chart gives the hazard indication associated with the signal words and the
estimated amounts required to kill a man when the pesticide is taken by mouth.
Signal Approximate amount needed to
Words Toxicity kill the average person
DANGER Highly Toxic A taste to a teaspoonful
WARNING Moderately Toxic A teaspoonful to a tablespoonful
CAUTION Low order of An ounce to more than a pint
toxicity
The FIFRA requires the name of the manufacturer or distributor on the
label so you will know who made or sold the product. Every pesticide
registered with EPA must have an EPA registration number. This number must
appear on the pesticide label. The EPA establishment number identifies the
factory (plant) that made the product. It does not have to appear on the
label but must be somewhere on each pesticide container.
-------
EXHIBIT 1 - SAMPLE ONLY
LOW-VOLUME 2 LB.
46.4%
53.6%
17505T
~Equivalent to 2,4-Dichlorophenoxyacetic Acid 34.3%
Contains 2.3 Pounds of 2,4-D Acid Equivalent Per Gallon
CAUTION
KEEP OUT OF THE REACH OF CHILDREN
SEE SIDE PANELS FOR ADDITIONAL CAUTIONS
Harmful if swallowed.
May cause skin irritation.
Avoid contact with eyes, skin and clothing. If contact with eyes occurs,
flush with plenty of water.
DO NOT store near fertilizers, seeds, insecticides or fungicides.
DO NOT contaminate irrigation ditches or water used for domestic purposes.
Use care to avoid spray drift to 2,4-D susceptible plants such as tomatoes,
flowers, grapes, fruit trees and ornamentals. Trace amounts of spray drift
may cause severe injury to both growing and dormant plants. Coarse sprays are
less likely to drift. Spray only on calm days using low pressure and lowered
boom. VAPORS may injure 2,4-D sensitive plants in the vicinty.
Flush sprayer out on suitable non-crop area after use. DO NOT use the same
spray equipment for applying other materials to plants as injury will result.
DO NOT reuse empty container. Return to drum reconditioner or destroy by
perforating, crushing and burying or disposing of in a safe place.
This product is toxic to fish. Keep out of lakes, ponds or streams. DO NOT
contaminate water by cleaning of equipment or disposal of wastes. Apply only
as directed on this label.
EPA REG. NO. 000-00-AA EPA EST. NO. 00-AA-1
MANUFACTURED FOR: ABC CHEMICAL COMPANY
345 MAIN STREET, SNOWHILL, MAINE 00000
-------
READ ENTIRE LABEL BEFORE USING Th'lS PRODUCT
GENERAL INFORMATION
LOW-VOLUME 2 LB. is a selective herbicide for control of many broadleaf weeds
in certain crops, around buildings, a'ong fence rows and pastures. A partial
list of weeds controlled by LOW-VOLUME 2 LB. is shown below:
Bindweed Lambsquarter Plaintain
Cocklebur Mustards Ragweed
Dandelion Morningglory Thistles
Knotweed Pigweed Wild Radish
NOTE: Local conditions, crop varieties, and application regulations varj* and
may affect use of this herbicide. Consult local agricultural experiment,,
station or extension agent and state regulatory agencies for recommendations
in your area.
Aerial application may be of use for control of weeds on certain crops where
there would be no danger of drift to susceptible crops. Applications should
only be made toy applicators experienced in the use of 2,4-0 formulations.
Regulations governing aerial application of herbicides are in effect in many
states. Consult local regulatory agencies concerning requirements befofe
making applications.
DIRECTIONS FOR USE
PREPARATION OF THE SPRAY: Fill the spray tank with half the required amount
of water. Then add the recoamended amount of LOW-VOLUME 2 LB. and continue
filling the spray tank with balance of water. Keep agitator running when
filling spray tank and during spray operations. The amount of water required
for low-volume applications may vary from 5 to 25 gallons per acre. For high
volume applications, 100 gallons or more of water will be needed for good
coverage. In any case, use the same amount of 2,4-D recommended per acre.
TIME OF APPLICATION: Best results are obtained when LOU-VOLUME 2 LB. is used
on young weeds that are actively growing. Applications of lower rates to
susceptible annual weeds usually will be satisfactory, but for perennial weeds
and other conditions, such as in very dry areas where kill is difficult, use
higher rates.
EXHIBIT 2 SAMPLE ONLY
SMALL GRAINS (Wheat, Barley, Rye): Apply LOW-VOLUME 2 L3. in sufficient water
for uniform coverage on small grains when fully tillered or stooled (4 to 3
inches tall), but before head emrges from the "boot". Crop injury may result
if applied earlier than "tiller" or later than "boot" stage. DO NOT use on
grain undersown with legumes, such as alfalfa or clovers, except where some
legume injury can be tolerated. DO NOT graze or feed forage from treated
fields within 2 weeks after treatment.
LAWNS, GOLF COURSES AND SIMILAR TURF: Apply 2 pints of LOW-VOLUME 2 LB. per
acre in sufficient water to provide uniform coverage. DO NOT apply to newly
seeded lawns until grasses become well established. Injury may result if
applied.to bentgrass, St. Augustinegrass and clovers in lawns.
AMOUNT OF LOW-VOLUME 2 L3. PER ACRE
CROP (See detailed directions) AMOUNT (Average conditions)
Small Grains - Annual Weeds 1/2 to 1 pint
Small Grains - Perennial Weeds 1 pint
Lawns, Golf Courses & Turf 2 pints
WOODY PLANT CONTROL: To control 2,4-D susceptible woody plants such as alder,
buckbrush, elderberry and willow on non-crop land and waste areas, use 2 to 3
quarts of LOW-VOLUME 2 LB. in 100 gallons of water. Wet thoroughly all parts
of the plants, including foliage and stems, to the point of run-off. Higher
volumes are necessary where the brush is very dense and over 6 to 8 feet
high. Applications are more effective when applied to actively growing
plants. DO NOT treat during periods of severe drought or in early fall when
leaves have lost their healthy green color. Hard to kill species may need
retreatment the following season.
GENERAL WEED CONTROL: Along fence rows, drainage ditch banks, roadsides,
industrial sites, around farm buildings and similar areas. Use 1 to 2 quarts
of LOW-VOLUME 2 LB. in 100 gallons of water per acre. Thoroughly wet all
foliage to run-off.
-------
- 5 -
CHAPTER 3
PESTICIDE SAFETY
Pesticides used to control the numerous pests that affect the production
of our food and fiber are toxic. The danger of a pesticide depends on a great
many things. One of the most important factors is the pesticide's relative
toxicity to man and pests.
A pesticide can cause severe illness or even death if it is misused.
Every user must be aware of the hazards to himself, to other people and the
surrounding environment. The user is responsible to help prevent accidents
with pesticides by following all directions on the pesticide label.
Choosing the correct pesticide to use is one of the most important
segments of carrying out an effective pest control program. The pesticide you
choose will be instrumental in the effectiveness of your control program. It
will have a direct bearing on the hazards to which you as well as other
persons and the environment are subjected. Actually a potential hazard may be
present the moment you purchase a pesticide. The selection of type of
pesticide, the formulation to be used and even the container type may be
factors contributing to a pesticide accident.
Pesticides are designed to be poisonous to kill
the pest for which they are used against. There are,
however, great ranges in the level of toxicity among
different pesticides. It is important that you have
a broad, general knowledge of the relative toxicity
of at least the most common pesticides used in your
particular area.
Exhibits 3 and 4 at the end of this chapter provide information on the
relative toxicity of some of the more common pesticides. The toxicity of a
pesticide is the capacity for that pesticide to produce injury. It is
expressed in terms of the amount of the pesticide per unit of weight of a test
animal needed to kill 50 percent of the population tested with a single dose.
This figure is called the LD50 for that pesticide. The LD50 is expressed as
one part of pesticide per one million parts of body weight of the test
animal. The acute toxicity of a pesticide is how poisonous it is to an animal
(or man) after a single exposure (single dose). (An LD50 may be expressed as
dermal (skin), oral (mouth) or inhalation (breathing)).
It is important to realize that the toxicity rating for any pesticide is
only approximate. The toxicity ratings on test animals can only be used as an
indication of relative toxicity to man. Always remember the lower the LD50
value the more toxic the pesticide.
Pesticides can enter the body by three routes: oral, dermal, and
inhalation.
-------
- 6 -
Oral - Pesticides can enter the body through
the mouth. Accidental splashing of liquid or
blowing of dusts or granules can enter the mouth
and cause poisoning. Smoking or eating food with
contaminated hands, allowing food to be exposed
to sprays or dusts and blowing on nozzles to clear
orificies also can cause pesticide ingestion. The most frequent cases of
accidental ingestion are those in which pesticides have been put in unlabeled
bottles or food containers or are stored where children can consume them.
Dermal - Pesticides can enter the body by absorp-
tion through the skin. It is the main route of entry
when liquid sprays and emulsifiable concentrate formu-
lations are used.
The degree of skin absorption depends upon the type and formulation of
pesticide and the part of the body with which the pesticide comes in contact.
Any break in the skin can enhance the entry of a pesticide into the blood
stream. Burns, dermatitis and eczema also may enhance the absorption of a
pesticide.
Inhalation - Pesticides may also enter the body
through the respiratory tract. Pesticides in the
form of dusts, spray mists and vapors are drawn into
the lungs rapidly and completely. Respiratory hazards
are greater when low volume/high pressure equipment is
used as opposed to conventional application equipment
that produces large droplets. The higher the application pressure the more
likely the chance of inhaling pesticides. Pesticides inhaled in sufficient
quantities may cause serious damage or irritation to nose, throat and lung
tissues or possibly death.
A pesticide that is highly toxic may be less hazardous to the public than
a pesticide of relatively low toxicity. The hazard of a pesticide is the
probability that injury or environmental damage will result from the use of
the pesticide. The relative hazard of a pesticide is reduced when the
pesticide is used properly. This includes application only to the sites
listed on the label, use of proper application and safety equipment and
applying only the dosage listed on the registered label. If a pesticide of
relatively low toxicity is used in a careless manner it has the potential to
cause more injury or environmental damage than a highly toxic pesticide used
properly.
Mixing Pesticides
Some pesticides are applied just as purchased and need no mixing. Other
pesticides need mixing with a carrier, water being the most common. The
following procedures should be followed when handling and mixing pesticides:
a. Open containers cautiously and pour carefully to avoid spilling,
*4
-------
- 7 -
b. Mix and prepare in the open or in well ventilated places. In close
quarters highly toxic pesticides may cause poisoning through
inhalation. If volatile, they can cause fires or explosions.
c. Make sure there is no chance of food, feed or water contamination,
d. Allow no children or pets to be present,
e. Use special containers reserved for or designed for mixing, bo not use
food or beverage containers,
f. Do not mix in concentrations higher than recommended,
g. Measure accurately to help avoid injury or environmental damage,
h. Use protective equipment and clothing if required by the pesticide
label. Avoid inhaling fumes, mists or dusts,
i. Avoid spilling concentrates on the skin or clothes and keep them away
from the eyes, mouth and nose. If any is spilled, wash it off the skin
with soap/detergent and water and change clothes immediately. Launder
contaminated clothing separate from other clothing before wearing it
again,
j. Do not smoke, eat or drink when mixing pesticides,
k. Use check valve in suction filler hoses to prevent resiphoning into
water sources. Do not allow tank to overflow. Never siphon pesticides
or pesticide mixtures with your mouth,
1. Empty pesticide containers thoroughly and rinse them three times before
disposing of them. Rinsate should be put into the spray tank,
m. Make sure when mixing pesticides together that they are physically and
chemically compatible,
n. Adjuvants may be needed to help the pesticide do a better job.
Applying Pesticides
The following procedures should be considered when applying pesticides:
a. If the pesticide label requires protective clothing, make sure you have
and use the proper clothing,
b. Do not apply dosages greater than those listed on the pesticide label,
c. Observe the danger of drift that may contaminate other areas,
d. Know what pesticides may be phytotoxic (chemically toxic) to plants,
e. Apply the pesticide only to crops or animals listed on the pesticide
label,
f. Time your application to prevent illegal pesticide residues on food,
feed or forage crops. Allow the prescribed number of days between the
last application and harvest,
g. Guard against run-off or drift that may contaminate water supplies,
fish-bearing waters or wildlife habitat,
h. Do not smoke, drink or eat when applying pesticides,
1. If you feel ill while applying pesticides, stop work at once and get
medical attention.
j. Always be sure to observe all re-entry precautions and restrictions.
-------
- 8 -
Protective Equipment
The best insurance against poisoning by
pesticides is to protect the routes by which
pesticides enter the body: oral, dermal and
inhalation. Good protection requires the
routine use of respiratory protective devices,
dermal protective garments and sound practices
of personal hygiene.
There is a wide variety of protective equipment available. The proper
selection and use of this equipment will depend on what is required by the
pesticide label and the type of work environment.
Dermal Protective Equipment
Impermeable Clothing - This type of clothing is made from rubber neoprene
or polyvinyl coatings on cloth fabrics. The coating material serves as a
barrier against liquid penetration. Clothing should be light enough to be
comfortable but heavy enough to be durable. Additional comfort can be gained
if a light color is selected.
Heavy Grade Cloth Coverings - Heavy grade cotton, one piece coveralls can
be used in most spray operations if spills from concentrated material are not
anticipated. They should be changed when noticeably wet, and washed after
each day's use in a strong detergent.
Head and Neck Covering - Impermeable (waterproof) head gear should be wprn
to protect the head, neck and hair from pesticide drift. Broad brimmed
waterproof rainhats and hoods will protect the ears and neck from downward
drift. Head gear should be washed frequently with water and detergent. Under
no condition should hats of felt or other absorbent materials be worn when
applying pesticides. Sweat bands should not be used since they can absorb the
pesticide and provide a continuous source of pesticide exposure.
Gloves - Unlined, impermeable gloves should be worn when using
pesticides. Heavyweight gloves, although more durable, should be avoided
because they restrict freedom of movement and are more likely to be removed
when working around spray equipment. Lightweight gloves should be checked
frequently for pinholes and breaks. Select gloves that are durable but which
provide reasonable movement of fingers.
Goggles - Protective shields or goggles should be used when there is any
danger of pesticides coming in contact with the eyes. Eye protection is most
often needed when measuring or mixing concentrated pesticides or when spray or
dust might be a problem. Goggles and eye shields should be kept clean at all
times.
-------
- 9 -
Boots - Waterproof footwear, generally rubberized boots, should be worn
when making any type of pesticide application. Never wear pant legs inside of
your boots. This may cause pesticides to run down the fabric and into your of
boots.
Respiratory Protective Equipment
A respiratory device should be worn any time you might inhale toxic
pesticides. A respirator should be worn when you may be exposed to a highly
toxic pesticide or if you are working in an enclosed area. Check the
information on the label for the type of respirator to use.
Chemical Cartridge Type - The cartridge type respirator is usually a
half-face mask that covers only the nose and mouth. Air is filtered and toxic
fumes and vapors are absorbed by one or two cartridges of activated charcoal.
This respirator is usually worn with goggles to give protection to the eyes.
Gas Mask Type - Gas mask respirators cover the entire face and protect
your eyes as well as your nose and mouth. Face pieces are made to hold a
container directly (chin style) or are connected to a canister with a flexible
hose (chest or back style). This type contains filters with more absorbing
material to cleanse the air than the cartridge type. Gas mask type
respirators may have a self-contained oxygen supply. Self-contained gas
masks must be used when an applicator may be exposed to high concentrations of
highly toxic pesticides in enclosed areas.
Care and Maintenance of Respirator Equipment - Every applicator using a
respirator should be knowlegdeable on proper selection, use and maintenance.
A good face piece fit is essential for effective protection with respirators
and gas masks.
The proper maintenance and care of respirators should include inspections
for defects, cleaning and disinfecting, repair and storage. They should be
inspected routinely before and after each use. An inspection check should
include tightness of connections and condition of the face piece, head bands,
valves, connecting tube and canister. Respiratory devices should be cleaned
after each day's use. Prior to cleaning, any filter, cartridge or canister
should be removed. The face piece and breathing tube should be washed with
warm soapy water, rinsed in fresh water to remove all traces of soap, and
sanitized if necessary. Respirators should be air dried in a clean area
separate from pesticide storage or other possible pesticide sources.
The respirator device, filters and cartridges should be stored, preferably
in a plastic bag or container, in a clean, cool, and dry place. When using a
respirator, the cloth filter should be changed twice a day or more often if
breathing becomes difficult. Cartridges should be changed after eight hours
of actual use or more often if an odor of the pesticide is detected.
-------
- 10 -
Personal Clean Up
The importance of personal cleanliness
and the proper care of clothing and protective
equipment cannot be over emphasized. Use com-
mon sense whenever you're handling pesticides.
Always wash your hands and face thoroughly
before eating, drinking or smoking. If clothes
become contaminated, change them immediately
and shower if necessary. Destroy clothing if
highly toxic concentrates are spilled or splashed
on them. Adequate cleaning of clothing contaminated
with concentrates is virtually impossible.
Wash all protective equipment thoroughly with warm water and detergent
after each use. Dry it completely and store in a secure area which is clean
and dry and away from all pesticides.
Remove clothing as soon as possible after you have finished working with
pesticides. All clothing must be washed thoroughly before you wear it again.
Never store or wash contaminated clothing with the family laundery and never
wash it in streams or ponds. The person washing work clothes should be made
aware of the potential hazards. Clothing should be washed in detergent and
hot water. Particular attention should be paid to belts and shoes which are
often not considered part of a clothing change and m«^y therefore be a source
of long term (chronic) exposure. Special care should be taken when wearing
leather belts and shoes since leather contaminated with pesticides cannot be
cleaned.
Take a shower at the end of each work day. Wash thoroughly with a
detergent, paying close attention to hair and fingernails. Put on a complete
change of clothing, including underwear.
Storage and Transportation of Pesticides
Always read the label for correct storage
procedures. Pesticides should always be stored in their
original, labeled container in a dry, locked, well
ventilated area where humans, livestock and pets cannot
come in contact with them. Stored containers should be
periodically checked for corrosion, leaks, breaks and
tears.
Storage facilities should be located away from populated areas and be well
marked to inform people of the hazards that exist. The storage structure
should be insulated and heated to keep pesticides from freezing and
overheating. All doors should be kept locked whenever the facility is not in
use.
-------
- 11 -
To reduce fire hazards, the structure should be constructed of fire
resistant material and fire fighting equipment should be made easily
available. To help fire fighting procedures, an inventory should be kept of
all pesticides stored.
The importance of preventing the spillage of toxic pesticides during
transportation cannot be overemphasized. Anyone transporting any chemical
should place it in the back of a pickup or truck with sufficient sides and
tailgate to prevent containers from rolling out. Fasten down all containers
to prevent them from tipping.
Spillage of a pesticide in transport must be considered an emergency
requiring prompt cleanup, protection of human health, safe disposal of damaged
containers and special care or disposal of damaged cargo.
Whenever a spill occcurs in transporting pesticides, acquire competent
help. The welfare of the people directly involved and the general public must
be protected.
All pesticide containers should be checked for damage and leaks before
transporting. The container label should be checked before transporting to
determine if special instructions are given for movement of the container. Do
not transport pesticides in the same compartment with food, feed, seed or
fertilizer.
Disposal of Pesticides and Containers
There has been an increasing recognition in recent years that improper
disposal of wastes can create serious hazards for both man and the
environment. The improper disposal of excess pesticides and containers can
lead to serious problems. While there are not, as yet, easy solutions to all
of the disposal concerns facing applicators, adherence to a few basic
guidelines can greatly reduce potential problems. All pesticide wastes must
be handled and disposed of properly.
Triple Rinse Empty Pesticide Containers - To triple rinse, empty the
pesticide into the spray tank and drain for a ha If-minute. Fill the container
10-20 percent with water (or other solvent in some cases) and rinse. Pour the
rinsate into the tank and drain again for a half-minute. Repeat the rinsing
procedure two more times. Unless otherwise provided for by label directions,
puncture and flatten the can so it cannot be reused.
Putting the rinsate into the spray tank serves the following purposes:
rinsates are used in the spray mixture itself and are not haphazardly dumped
on the ground and you get the most out of your pesticide dollar. If rinsates
are not put into the spray tank, you must: (1) use them subsequently on a
crop or other site listed on the label and in accordance with label
directions, (2) use them to mix future solutions of the same pesticide or (3)
dispose of them in accordance with all label directions.
-------
- 12 -
Safely Dispose of Rinsed Containers - Farmers can legally bury
triple-rinsed containers on their own land. This must be done conscientiously
while taking into account all appropriate precautions. Be careful not to bury
them near wetlands, streams, ponds or other surface waters. Under no
circumstances should rinsed containers be carelessly discarded.
Some local landfills are authorized to accept triple-rinsed containers.
In order to determine which landfills will accept these containers, you should
check with your local health department or county extension agent.
Empty pesticide bags may be burned if local air pollution regulations
permit. When burning bags, make sure that you do not come into contact with
the smoke. The smoke from the bags could be a source of pesticide poisoning.
Recycle Empty Containers - A number of pesticide dealers and manufacturers
will accept pesticide containers for reuse. You should check with your local
pesticide dealer or salesman to find out which companies will accept used
containers.
Symptoms and Signs of Pesticide Poisoning
You should know what kinds of sickness are
caused by the pesticides you use. You should
also know the conditions under which each one
m^y make you sick. There are two kinds of
clues to pesticide poisoning. Seme are feel-
ings that only the person who has been poisoned
can notice such as nausea or headache. These
are called "symptoms". Others, like vomiting, also can be noticed by someone
else. These are "signs". So you should know what your own feelings might
mean and what signs of poisoning to look for in others who may have been
exposed to a pesticide.
All pesticides in the same chemical group cause the same kind of
sickness. This sickness rosy be mild or severe depending on the pesticide and
the amount absorbed. The pattern of illness caused by one type of pesticide
is always the same. Having some of the signs' and symptoms does not always
mean you have been poisoned. Headache and a feeling of being unwell, for
example, may signal the start of many kinds of illness. It is the pattern of
symptoms that makes 1t possible to tell one kind of sickness from another.
Organophosphates - These pesticides injure the nervous system. The signs
and symptoms go through stages. They normally occur in this order:
Mild Poisoning
fatigue,
headache,
dizziness,
-------
- 13 -
blurred vision,
too much sweating and salivation,
nausea and vomiting,
stomach cramps or diarrhea.
Moderate Poisoning
unable to walk,
weakness,
chest discomfort,
muscle twitches,
constriction of the pupil of the eye,
earlier symptoms become more severe.
Severe Poisoning
unconsciousness,
severe constriction of the pupil of the eye,
muscle twitches,
secretions from the mouth and nose,
breathing difficulty,
death if not treated.
Illness may be delayed a few hours. But if signs or symptoms start more
than 12 hours after you were exposed to the pesticide, you probably have some
other illness. Check with your doctor to be sure.
Carbamates - The only carbamates likely to make you ill act almost like
organophosphates. They produce the same signs and symptoms if you are
poisoned by them. However, the injury they cause can be treated more easily
by a doctor. For this reason, most carbamates are safer than organophosphates.
Organochlorines - Not many applicators have been poisoned by
organochlorines (chlorinated hydrocarbons). Early signs and symptoms of
poisoning include:
headache,
nausea,
vomiting,
general discomfort, and
dizziness.
With more severe poisoning, convulsions follow. They may even appear
without warning. Coma may follow the convulsions. The person may also be
unusually excited or irritable.
Nitrophenols and Pentachlorophenol - The signs and symptoms of skin
exposure include:
redness,
burning, and
blisters.
-------
- 14 -
The signs and symptoms of poisoning include:
headache,
nausea,
gastric distress,
restlessness,
hot feeling,
flushed skin,
sweating,
deep and fast breathing,
fast beating of the heart,
fever,
ashen color,
collapse, and
coma.
Severe poisoning usually runs a rapid course. Within 24 to 48 hours one
usually dies or is almost well.
Fumigants and Solvents - Too much exposure to the these compounds may make
a person seem drunk. The signs and symptoms are:
poor coordination,
slurring words,
confusion, and
sleepiness.
Repeated exposure to the funigant methyl bromide has caused permanent
internal injury without early signs or symptoms of poisoning. You can absorb
a fatal dose of it before symptoms appear.
Inorganic Pesticides - Large single doses of most inorganic pesticides
cause vomiting and stomach pain. The signs and symptoms depend on the mineral
from which the pesticide is made. If you will be using an inorganic
pesticide, you should consult your local doctor for signs and symptoms of
poisoning of the particular pesticide(s) you are using.
Plant-Derived Pesticides - Some plant-derived pesticides are very toxic.
Technical pryethrunr may cause allergic reactions. Some rotenone dusts
irritate the respiratory tract. Nicotine is a fast acting nerve poison about
as dangerous as parathion. Some other plant-derived pesticides are strychnine
and red squill.
First Aid For Pesticide Poisoning
Federal regulations require that where a pesticide hazard exists,
appropriate first aid statements must appear on the pesticide label. Those
pesticides which are considered highly toxic on the basis of oral, inhalation
or dermal toxicity must have a statement of practical treatment on the label.
Practical treatment statements on the label are your first source of
information. You should also be thoroughly familiar with basic first aid
procedures. This knowledge could help prevent serious injury or death.
-------
- 15 -
Always remember that first aid procedures are just that - they are your
first response to pesticide exposure. They are not a substitute for
professional medical help. You should be aware of the importance of knowing
when professional medical help is needed. If in doubt, seek medical attention.
Your response to a pesticide poisoning obviously depends to some extent on
whether you or someone else is the victim. The same basic first aid
principles must be followed in either case. If you are exposed to a pesticide
when you are working alone, remain calm. The serious effects of pesticides
are generally not instantaneous so you will have some time to respond
properly. If you act intelligently, you will minimize any adverse effects and
you may save your life.
In the event of an accident, you should immediately begin proper first aid
procedures and get help. If you have been exposed to a highly toxic pesticide
or if you begin to feel ill, you must get to a doctor. If you are with
someone else who is exposed to a pesticide, immediately begin first aid
treatment or assist the victim in any way you can. Even where the pesticide
is less toxic it may be advisable to seek medical attention, particularly if
you were exposed to a high amount of the pesticide. If you swallow a
pesticide or get some in your eyes, always see a doctor irrmediately. Have
someone take you to the doctor. Make sure that the label or the labeled
container is given to the doctor. Do not take the container in the passenger
compartment with you. In order to help prevent serious injury or death, you
should work with someone else when mixing or applying pesticides.
General First Aid Instructions
If oral or dermal exposure has occurred, your first objective 1s usually
to dilute the pesticide as quickly and as effectively as possible. You should
have a supply of water readily available when you're working with pesticides.
You can use any source of fairly clean water, including water from lakes,
streams, ponds, watering troughs, etc.
If inhalation exposure has occurred, get to fresh air immediately. If
you're with someone who has been exposed to a pesticide and if his or her
breathing has stopped, give mouth-to-mouth resuscitation. If you Work with
pesticides very often, you should learn how to give mouth-to-mouth
respiration. Never try to give any liquids or medication orally to an
unconscious person.
Specific First Aid instructions
Specific first aid treatment varies according to the type of exposure.
You should become thoroughly familiar with all of the appropriate procedures.
They should be learned prior to the time of an accident since you probably
won't have the time or the opportunity to look them up if you ever need them.
-------
- 16 -
Dermal Exposure
Remove clothing if it has been contaminated,
Drench skin with water,
Wash thoroughly including hair if necessary. Detergent and commercial
cleansers are better than soap,
Rinse thoroughly. Use rubbing alcohol if it is readily available rather
than water,
Wash again and rinse,
Dry and wrap in a blanket,
Where chemical burns of the skin have occurred, cover the area loosely
with a clean, soft cloth. Avoid the use of ointments, greases, powders and
other medications.
Inhalation Exposure
Get to fresh air immediately,
If you're with someone who has been poisoned, carry the victim to fresh
air immediately,
Do not attempt to rescue someone who has been poisoned in an enclosed area
if you do not have the proper respiratory equipment,
Loosen all tight clothing,
If breathing has stopped, give artificial respiration,
Victim should remain as quiet as possible,
Prevent chilling (wrap in blankets but don't overheat),
If you are with a victim who is having convulsions, watch his breathing
and protect him from falling and striking his head. Keep his chin up so his
air passages will remain free for breathing,
Do not give alcohol to the victim.
Eye Exposure
Hold eyelids open and wash eyes with a gentle stream of clean running
water. Use large amounts of water. Do so immediately, delay of even a few
seconds greatly increases the possiblity of permanant injury, continue to wash
for 15 minutes or more.
Do not use medications in the wash water.
Oral Exposure
If a pesticide has gotten into your mouth but has not been swallowed,
rinse your mouth with large amounts of water.
If a pesticide has been swallowed, the most important consideration is
whether or not to induce vomiting. The decision must be matte quickly and
correctly. Where specific instructions are given on the pesticide label,
always follow them. Beyond that NEVER induce vomiting if:
a. the victim is unconscious or is having convulsions,
b. the pesticide is corrosive. (A corrosive substance is any material
such as a strong acid or alkali (base) which causes chemical destruction
of living tissue. Poisoning symptoms include severe pain and a burning
sensation in the mouth or throat-;)
-------
- 17 -
In attempting to induce vomiting it is important to use safe and effective
procedures. Vomiting should be induced with two tablespoons (one ounce) of
Syrup of Ipecac and two glasses of water for an adult or one tablespoon
(one-half ounce) of Syrup of Ipecac and one glass of water for a child. If
Syrup of Ipecac is not available, induce vomiting by drinking 1 or 2 glasses
of water then touching the back of the throat with your finger. Salt water
should not be used to induce vomiting. The victim should be lying face down
or kneeTTng while vomiting. This will prevent the victim from swallowing the
vomitus which could cause further damage. Oo not spend a lot of time
attempting to induce vomiting. Get to a hospital as soon as possible.
Where the label identifies specific antidotes, this information is
intended for use by a doctor. Antidotes should not be administered except
under the direction of a physician or other medical personnel. Taken
improperly, antidotes can be more harmful than the pesticide itself.
The name, address and telephone number of the physician, clinic or
hospital emergency room that will provide care in the event of an accident
should be clearly posted at all work sites.
-------
topp
1.05
phorot* fThlm«t®)
1.1-2.3
d*m*ton (Syitox®)
2.5-4.2
porathion (Thiophos®)
3.6-13.0
mcrinphoi (Phoidrin®)
3.7-6.1
•ndrin
5-17.8
carbophvnothion (Trithion®)
10-30
azInphounOhyl (Guthlon®)
11-13
m«lhyl parathion
14-24
Bidrin®
15-22
•ndoiulfan (Thiodan®)
18-43
phoiphamidon (Dimecron®)
23.5
•thion (Nialat*®)
27-65
aldrin
39-60
divldrin
46
diazinon
76-108
toxaph«n«
80-90
DDT
113-118
diiMlhoat* (Cygon®)
215
chlordon*
335-430
naiad (Dibrom®)
430
corboryl (Savin®)
500-850
trichlorofon (Dylox®)
Dipt* rax®)
560-630
dkofol (Kalthona®)
1000-1100
¦no lath ion
1000-1375
chlorobanzilata
1040-1220
Aromita
2000-3900
fatrodifon (Tedion®)
5000-14700
ACUTE ORAL LD„ Ron mg/kg
TK« thortor th* bar—th« mora toxic the chMikal
If inqttfd
f >
BEFORE USING ANY
PESTICIDE
READ THE LABEL
V
m
x
tc
M
w
M
H
U>
100
200
300
400
500 600
mg/kg
700
800
900 1000 2000
5000
-------
lepp
phorate (Thimet®)
mavinphoi (Phoidrin®)
parathion (Thiophoj®)
demeton (Syitox®)
•ndrin
carbophenothion (Trilhion®)
dieldrin
ethion (Nialate®)
methyl parathion
endoiulfan (Thiodon®)
aldrin
phoiphamidon (Dimecron®)
azinphotmethyl (Gulhion®)
Bidrin®
oxydemetonmethyl (Meta Syitox® ¦
dimethoate (Cygon®)
diazinon
chlordane
toxophene
lindane
dicofol (Kelthane®)
ACUTE DERMAL ID.0 Rati mg/kg
The shorter the bar—tha mora toxic tha chemical
if contact with skin occuri
r >
PES1ICI0E
naled (Dibrom©)
1100
trichlorofon (Dylox®, Dipterex®)
>
2000
DDT
2510
corbaryl (Savin®)
>
4000
malathion
>
4444
tetradifon (Tedion®)*
>
10000
> = greater than
' rabbin
READ THE I ABEL >
100
200
300
400
500
600
700 800
900
Above Above Above
1000 2000 4000 10000
-------
- 18 -
CHAPTER 4
PESTICIDES
A pesticide may be defined as any
chemical used by man either to directly
control pest populations or to prevent or
reduce pest damage. Although the ending
"cide" is derived from the Latin word
"cida", meaning "to kill", not all
pesticides actually kill the target
organism. For example, some fungicides may
simply inhibit the growth of a fungus without killing it. Attractants and
repellants serve only to lure a pest to or divert it from a particular site.
The FIFRA has extended the legal definition of a pesticide to include
compounds intended for use as plant growth regulators, defoliants, and
desiccants. There are a number of ways which pesticides can be classified:
chemical, formulation or pest(s) the pesticide is designed to control. Most
pesticides are classified by the pest they will control. The major groups of
pesticides according to this classification are:
Attractants - any chemical substance used to lure insects, rodents or
other pests to selected locations where they may then be captured or destroyed.
Avicides - any chemcial substance used to control bird populations.
Bactericides - any chemical substance which kills or inhibits the growth
of bacteria: sometimes referred to as disinfectants or sanitizers.
Defoliants - any chemical substance used to cause leaves or foliage to
drop from the plant.
Dessicants - any chemical substance used as a harvest aid to dry up plant
foliage.
Fungicides - any chemical substance that kills, controls or repels fungi.
Herbicides - any chemical substance used to control undesirable plants.
Insecticides - any chemical substance used to control insects and other
related pests such as: ticks, spiders, centipedes, sow bugs and pill bugs.
Miticides or Acaricides - any chemical substance used to control mites.
Molluscicldes - any chemical substance used to control slugs, snails and
barnacles.
Nematicides - any chemical substance used to control worm-like microscopic
organisms call nematodes.
Piscicides - any chemical substance used to control undesirable fish.
Plant Growth Regulators - any chemical substance used to alter the growth
or modify normal plant processes.
Repellant - any chemical substance that may be unpalatable, unpleasant or
annoying to certain organisms.
Rodenticides - any chemical substance used to control rodents.
Predacides - any chemical substance used to control, destroy or repel
predators.
-------
- 19 -
Pesticides can also be classified by their chemical origin. The three
major groupings by chemical origin are: synthetic organic pesticides,
inorganic pesticides, and botanical pesticides.
Synthetic organic is the largest group and it consists of man-made
compounds from carbon and hydrogen and several other chemical elements. The
majority of pesticides being used at the present time and those in the
developmental stage are in this group. Synthetic pesticide developments have
greatly improved the performance and pest selectivity of present day chemicals
being used for pest control. Many common pesticides are in this group: 2,4-D,
captan, malathion, carbaryl and atrazine.
Inorganic pesticides were the first pesticides used. These included
arsenic, boron, copper, mercury and sulphur. Several of the pesticides
presently being used are inorganic in nature.
Botanical pesticides are derived from plant materials. Examples are
rotenone, pyrethrins and strychnine.
Pesticides are also commonly classified by formulation. There are many
types of pesticide formulations available and considerable research work is
being conducted for new developments. The most commonly used formulations are
emulsifiable concentrates, wettable powders, dusts, granules and aerosols.
Emus1 ifiable Concentrates (E.C.)
A liquid formulation which has the active ingredient dissolved in one or
more water-insoluble solvents. Emulsifiers are generally added to ensure
mixing with oil and water. E.C.s usually contain 10-80 percent (1-8
lb./gallon) of active ingredient. Those formulations which contain over eight
or more pounds per gallon are referred to as high concentrate liquids.
Emulsifiable concentrates readily remain in suspension with water or oil and
are easy to handle. Care must be taken when using high toxicity pesticides in
this form because many of them are readily absorbed by the skin. Emulsifiable
concentrates sometimes pose chemical compatibility and phytotoxicity problems.
Wettable Powders (WP)
The powder form of a pesticide which can be added to water to form a
suspension. They are similar in appearance to dusts but they contain wetting
agents to keep particles from floating and dispersion agents to maintain the
particles in suspension. Agitation is needed in spray tanks to keep wettable
powders in suspension when applications are made. Wettable powders generally
contain 15-75 percent active ingredient. Wettable powders with the highest
percentage of active ingredient are generally more desirable to use because
they often have less noticeable residue and cost per-unit of active ingredient
is less. Some pesticide products can only be prepared as wettable powder
formulations due to the chemical nature of the active ingredient. These
formulations are some of the safest to use when phytotoxictty or compatibility
might be a problem. Sometimes hard or alkaline water may, cause difficulty
when mixing wettable powders. Application equipment should be checked
frequently when using wettable powders as they are noted to Gause excessive
wear to pumps and nozzle tips.
-------
- 20 -
Flowables (F)
Flowable powder formulations are often manufactured when the active
ingredients can only be produced in the form of solids or semi solids. These
pesticides are sometimes formulated as flowable powders in which the active
ingredient is finely ground and suspended in a liquid along with special
suspending chemicals and additives. The advantage of these over conventional
wettable powders is the ease in which they can be mixed into water to form a
suspension.
Soluble Powders (S.P.)
Soluble powder formulations are like wettable powders in appearance.
Soluble powders, however, unlike wettable powders will dissolve and form true
solutions when added to water. Once forming a true solution or becoming
completely dissolved, soluble powders do not require agitation in the spray
tank. There are very few pesticides available as soluble powders and existing
formulations contain 50 percent or more active ingredient.
Dusts (0)
Mixtures of one or more pesticides in finely ground diluent such as talc,
clay or volcanic ash. Ousts are prepared to be used as dry applications and
should never be mixed with water. Dusts are easier to handle from the
standpoint of preparation than either emulsifiable concentrates or wettable
powders. They are generally ready to use as purchased and will generally
contain 1-10 percent active ingredient. The potential danger of drift from
the target area is greater with dusts than with other formulations.
Granules (G)
Dry formulations with the pesticide ingredient being impregnated upon a
carrier the size of sand grains or larger. Carriers are often inert materials
such as clay, ground up corn cobs or walnut shells. This formulation has the
least potential for drift during application and from this standpoint has
considerable advantage over other types of formulations. Granules are
generally available containing 1-40 percent active ingredient. Granules are
easy to handle and are very desirable for homeowners to use as long as
spreaders are first calibrated for the material being used. They are
generally more expensive per unit of active ingredient, however, the low cost
for application and variety of uses are responsible for their increase in
popularity.
Aerosols (A)
Pesticides particles ere in a can under pressure. When used, liquid
particles are dispensed as a foam, mist or fog. One or more pesticides are
used in the same formulation. As the valve is released, the contents are
ejected by a propellant. The percentage of active ingredient is generally
very low in aerosols and they are used quite extensively by homeowners. They
are convenient and easy to use. However, the unit cost of the active
ingredient is very expensive.
-------
- 21 -
Fumigants
These are formulations of gas, liquid or solid which will produce a gas,
vapor, fume or smoke. Their use is primarily for control of pests in closed
structures, greenhouses and soil. They contain a pesticide or mixture of
pesticides, a diluent and generally a substance having a characteristric odor
to serve as a warning to the applicator or other persons in the area of use.
They are one of the most hazardous formulations to use and extreme caution
should be taken when they are used. Because of their hazardous nature, they
are not generally reconmended for home use.
Miscellaneous Formulations
There are several other formulations of pesticides available but less
commonly used. These include:
Water soluble concentrates,
Oil soluble concentrates,
Oils,
ULV,
Invert emulsions,
Prepared baits, and
Bait concentrates.
Water soluble concentrates are completely soluble in water and form true
solutions, not suspensions, when added to water.
Oil soluble concentrates are similar in appearance to emulsiftable
concentrates except they will not mix with water. They are generally diluted
with fuel oil, diesel oil or kerosene.
Oils used in some phases of pest control are low cost, spread easily over
a surface, have excellent absorption and are relatively easy to mix and handle.
ULV (ultra low volume) are forms of concentrate materials and are
formulated to be used directly without further dilution.
Invert emulsions are water in oil mixtures in which each water doplet is
surrounded by oil. Some difficulty has been encountered in applying invert
emulsions due to high viscosity. Their apparent advantage is to reduce drift
potential in low volume and aerial applications-.
Prepared baits have been used for insect and rodent control quite
extensively. They are ready to use and provide adequate pest control when
strategically placed.
Bait concentrates ms*y be liquids or solids which are diluted with food or
liquids before use.
In most cases, it is economical to purchase pesticides with the highest
percentage of active ingredient and dilute to the desired concentration. On a
unit of active ingredient basis, there is less filler or carrier, and shipping
costs are lower on higher percentage concentrated pesticides. In some
instances, pesticides me
-------
- 22 -
Pesticides can also be classified according "to how they work. Each
pesticide label will tell you how the pesticide works. The major groups of
pesticides based on how they work are:
Protectants - applied to plants, animals, structures and products to
prevent entry or damage by a pest,
Sterilants - make pests unable to reproduce,
Contacts - kill pests simply by coming into contact with them,
Stomach poisons - kill when swallowed,
Systemics - taken into the blood of an animal or sap of a plant. They
kill the pest without harming the host.
Translocated Herbicides - kill plants by being absorbed by leaves, stems
or roots and moving throughout the plant,
Anticoagulants - prevent normal clotting of the blood,
Selective - more toxic to some kinds of plants or animals than to others,
Non-selective - toxic to most plants or animals,
Pheromones - affect pests by changing their behavior.
Restricted Use/General Use?
Another way in which pesticides are classified is by restricted use or
general use. This type of classification is required by the amended FIFRA.
The FIFRA provides that a pesticide use shall be classified as restricted if
the Administrator of EPA determines that the use of the pesticide, when
applied in accordance with its directions for use, warnings and cautions, or
in accordance with wide-spread and commonly recognized practices, may
generally cause, without additional regulatory restrictions, unreasonable
adverse effects on the environment, including injury to the applicator.
Prior to the enactment of the amended FIFRA, if a pesticide posed a threat
to man or the environment, the only legal action available to EPA was to
cancel the use of the particular pesticide. This type of action denies the
use of the pesticide to everyone. By classifying pesticides for restricted
use, EPA can now allow the use of some pesticides to continue while
restricting their use to only qualified (certified) applicators. The
classification of pesticides and the certification of applicators has
permitted EPA to allow the continued use of a number of pesticides which might
have otherwise been subject to cancellation.
When considering whether or not to classify a pesticide for restricted
use, EPA takes into account a number of items. These include: 1) the
accident history associated with the pesticide, 2) the pesticide's acute
(immediate) toxicity or chronic (long-term) toxicity, and 3) the pesticide's
hazards or potential hazard to non-target species.
Accident History - When reviewing a pesticide's accident history, EPA
reviews all available data on the pesticide's past use. This includes
research data provided by the pesticide manufacturer, independent research
groups, and the USDA Extension Service. EPA also examines enforcement actions
it has taken or actions taken by individual state pesticide enforcement
agencies as well as information provided by poison control centers. This data
helps EPA make a sound determination on whether or not a pesticide should be
classified for restricted use based upon it's past use history.
-------
- 23 -
Toxicity - The toxicity of each pesticide which is being considered for
classification as restricted use is reviewed. Pesticides which are highly
toxic to man or other organisms which might come into contact with it may be
classified for restricted use based upon this toxicity. The concentration of
the pesticide is also taken into consideration. The higher the concentration
of a pesticide, the more likely it may be classified for restricted use.
Hazard to Non-target Species - A number of pesticides do not readily pose
a hazard to the applicator. However, the pesticides may have characteristics
which may be hazardous to non-target species. An example is pesticides which
are very persistent in the environment or pose secondary poisoning hazards.
After EPA has reviewed all of the information on a particular pesticide
and makes a determination that all or some of its uses should be classified
for restricted use, it will publish a notice in the Federal Register
announcing its decision and ask for public comment. Based upon the input EPA
receives, the Agency will make a final determination on the classification of
the pesticide being considered. This classification can range from all uses
being classified as restricted to none of the uses being classified as
restricted. After a final determination that a pesticide will be classified
as restricted use, EPA will notify the pesticide manufacturer. The
manufacturer will be given a certain number of days in which to change the
product labeling.
-------
- 24 -
CHAPTER 5
PESTS
Man's success in a hostile environment
is determined by his ability to adapt or to
change his surroundings to his benefit. An
area in which man does not exist has no pests.
"Pest" is a man-made concept and is generally
considered to include those organisms which
come into conflict with him for his crops and
livestock, affect his health or comfort or
destroy his property.
Man prefers certain plants and animals that provide him food and fiber.
But man also provides good growing conditions for other plants and animals
that harm him or his crops. These living things that compete with man for
food and fiber or attack him directly are pests. The living plant or animal a
pest depends on for survival is called the host.
The first step in solving any problem is to understand what is causing
it. So the first step in pest control is to recognize the pests you need to
control.
Pests can be put into five main groups:
Insects (plus mites, ticks, and spiders),
Snails and slugs,
Vertebrates,
Weeds, and
Plant disease agents.
INSECTS
Insects thrive in more environments than any other group of animals.
There are well over one million species of insects in the world. They live
not only on the earth's surface but within the soil and in water. They are at
home in deserts, rain forests, hot springs, snow fields and dark caves. They
eat the choicest foods of man's table. They can even eat the table.
Many types of insects affect many types of crops. They cause damage in a
variety of ways* They may feed on leaves, tunnel or bore in stems, stalks,
and branches, feed on and tunnel in roots, feed on and in seeds and nuts, suck
the sap from leaves, stems, roots, fruits and flowers and carry plant disease
agents.
The plants can be damaged, weakened or killed. This causes reduced
yields, lowered quality and ugly plant or plant products that cannot be sold.
Even after harvest, insects continue their damage 1n the stored or processed
products. Insects also feed on and in man and other animals. Some of these
pests carry disease agents which have caused millions of deaths to man and
livestock. However, not all insects are pests. Some help man by doing such
things as pollinating plants or feeding on other insects that are pests.
-------
- 25 -
Recognizing Common Features of Insects
MEN
\
THORAX
All adult insects have two things in
common - they have six legs and three body
parts (head., thorax and abdomen). But how do
you tell one insect from another? The most
important parts to look at are wings and
mouthparts. Some insects have no wings. Other
insects may have two or four wings. When wings
are present, they are found on the thorax of
the insect. The insect's legs are also found
in the thorax. The wings vary in shape, size,
thickness and structure.
As mentioned previously, the mouthparts are very important when trying to
identify an insect as well as when selecting the proper pesticide to control
the pest. There are two major types of mouthparts - chewing and sucking.
Chewing mouthparts are generally composed
of a labrum (upper lip), a pair of cutting or
crushing mandibles, a pair of maxillae, a labium
(lower lip) and a tongue-like hypopharynx. The
mandibles and maxillae, or jaws work sideways
and are used to cut off and chew or grind solid
food. A typical example is the type of mouthparts found in a grasshopper or
cricket. In some forms of insects, mainly predators, the mandibles are long
and sickle shaped. In others, such as honey bees, the hypopharynx or tongue,
is greatly modified.
Insects with chewing mouthparts include adult grasshoppers and crickets,
dragon flies, damsel flies, lace wing flies, beetles, bees, ants and wasps.
Sucking mouthparts are those in which the parts described
above are highly modified into some form of organ for securing
liquid food. They may be piercing-sucking as in the mosquitoes,
true bugs, aphids and stable flies; lapping or sponging as in
the house fly; rasping-sucking as in the thrips or tube like
as in the moths and butterflies.
Most insects change from the time they hatch from eggs until they are full
grown. This change in form is called metamorphosis. It may be a rather
gradual change involving little more than an increase in size to a very
dramatic difference between the young and the adult.
There are several ways of characterizing the types of metamorphosis but
the generally used method is to divide them into simple or incomplete and
complete.
In the simple type of metamorphosis the insects which hatch from the eggs
are called nymphs. As they feed and grow, they shed their skins or molt. In
the winged species wings first appear as pad-like buds on the nymphs. Each
-------
- 26 -
stage between molts is referred to as an instar. There is no prolonged
resting period before the adult stage is reached. Insects which have simple
or incomplete metamorphosis are: dragon flies, grasshoppers, crickets,
termites, chewing lice, sucking lice, thrips, aphids and leafhoppers.
EGG NYMPHS ADULT
The complete metamorphosis involves a very major change in form between
the young and the adult. In the winged forms the wings develop internally
instead of externally. The typical development involves the egg, larva, pupa
and adult. The larvae may go through a number of instars and molts as they
grow. The pupae may take several forms. They may be exposed or contained in
a capsule like a silken cocoon. Some types of insects which undergo complete
metamorphosis are: lace wings, beetles, moths, butterflies, mosquitoes,
fleas, bees, ants, and wasps.
Common Agricultural Insect Pests
CORN
Corn Rootworms
The Western corn rootworm 1s one of the most predominant soil insects
attacking corn. It is only a problem in ground that 1s planted to corn for
more than one year. This insect overwinters as eggs that are deposited by the
adult female beetle in late summer and fall. The eggs hatch the first part of
June and the young worms begin to feed on the roots of the new plant. The
rootworms are very small, only about one-half inch long when fully grown, a
dirty white color with dark heads and a slender body. When the worms mature,
they pupate in the soil. Adult beetles come out the latter part of the summer
to feed on pollen and silks, mate and lay eggs. Destruction of the silk can
cause ears to develop poorly. Adult beetles are greenish-yellow in color,
about one-half inch long and marked with black stripes or marks on the wing
cover.
-------
- 27 -
European Corn Borer
The European corn borer overwinters as a mature larvae in a tunnel within
the stalk, stubble or corn cob. In May the larvae pupates inside it's tunnel
and forms a brown, cigar-shaped pupa. The adult form or moth comes out in
June. The actual time of moth emergence, mating and laying of eggs will
depend upon spring conditions. Cooler weather will slow down emergence and
warmer weather will speed it up. The female moth is small with a wingspread
of about 1 inch and is pale yellow to light brown in color. The outer third
of the wings is usually crossed by two dark zig zag lines. Male moths are
smaller and darker in color. Moths are attracted to the tallest and most
vigorous corn growing in the area. Eggs are generally laid near the
mid-ribs. Eggs hatch in a circular pattern. Eventually the larvae will bore
into the stalks.
When first brood infestations are heavy, yields may be seriously
affected. Larvae will complete their development, pupate and a second moth
flight will occur. The second brood moth flight is somewhat erradic and can
extend from July to September. Eggs from the second generation usually are
laid around the ear. The second brood larvae are destructive in that they are
responsible for a lot of stalk breakage below the ear and a lot of ear
droppage because of feeding on shanks.
ALFALFA
Alfalfa Weevil
This insect is one of the most serious insect pests of alfalfa in many
areas of the West. During years of peak populations, worms or larvae counts
m^y reach to a hundred per sweep of an insect net. Such populations will
reduce the alfalfa to just stems. Damaged hay will lose most of its carotene
and protein content. Primary damage is to first cutting although larvae may
attack new growth on second cutting if not controlled. Alfalfa weevils like
to feed on the upper parts of the plant and between leaf veins. A damaged
field can be recognized from a distance by its characteristic grayish cast.
The adult weevil (snout beetle) overwinters in the soil or crown of the
plants. It makes its appearance in early spring as soon as or before the
weather is warm enough to start the hay. Some eggs may be deposited in
crevices in the old stubble. However, the preferable location is inside the
stems of the new growth. The female beetles chew a small hole in the stem and
then inserts the eggs inside. From 2 to 25 eggs are laid in each stem. The
female is capable of laying 600-800 eggs during about a 30 day period.
The eggs at first are yellow and are easily visible if an infested stem is
broken open. Upon hatching, the larvae make their way to the new growth.
Characteristically, they curl over the edge of the leaf while feeding. At
first they are very tiny (1/16 of an inch). When full grown they measure
about 1/3 of an inch, are light green in color with a median white stripe on
the back and on each side. The larval period is about three weeks. If the
hay is cut before the larvae stop feeding, they will drop to the ground and
some will reach the crown where they feed on the new shoots. This often
retards the second cutting a week or so.
-------
- 28 -
The alfalfa weevil pupates in a flimsy silken cocoon in the crown of the
alfalfa. The cocoon may be partially concealed by folded leaves. There is
only one generation a year. The adults that emerge from the cocoons in mid
summer hibernate through the winter.
Pea Aphids
The pea aphids development is favored by cool dry weather and when this
occurs, they can cause considerable damage. In outbreak years, early
infestations usually appear in the lower elevations in the river valleys and
as the season progresses the aphids move to the higher elevations. The aphids
suck out the plant juices. Infested alfalfa is often stunted, misshaped and
has a pale or yellowish cast. Seedling plants are often killed. Heaviest
aphid populations occur in the spring and early summer but they may persist
throughout the growing season.
Usually when pea aphids are abundant, a number of predators such as the
lady beetle and lacewings will develop. Generally, the predators do not
appear in sufficient numbers until much of the aphid damage has been done.
Later predators and parasites may catch up and bring the aphids under control.
The pea aphid is one of the larger aphid species, 1/6 inch long and
pea-green in color. Both winged and wingless forms may be present. A
complete cycle may require only 2 weeks. Consequently, several generations
are produced each year.
BEANS
Mexican Bean Beetle
The mexican bean beetle is usually present to some extent each year and
control is usually necessary. Both the adult beetles and larvae feed on
plants. The leaves are skeletonized and often the pods are attacked.
The adult beetle is copper colored with black spots on the wing covers.
It comes out of hibernation in late May, it feeds for a short period and then
lays its eggs, in clusters on the underneath surface of the leaves. In a few
days the eggs hatch, producing yellow larvae which consimfie much of the leaf
tissue. The larvae are about 1/3 inch long when fully grown. They pupate on
the leaves. The beetle can complete its life cycle in about a month. There
may be 2 or 3 generations during the growing season.
SMALL GRAINS
Army Cutworms
This cutworm is a subterranean species commonly found damaging winter
wheat early in the spring. The mature cutworm is dull green to brown in color
with a faint pale yellow stripe down the back and some brown freckles on the
head capsule.
-------
- 29 -
The army cutworm has one generation per year. The eggs hatch in 1 to 2
weeks and the young larvae feed until cold weather. They pass the winter as
partly grown larvae. They probably feed occasionally in the warm weather
during the winter months. As soon as the weather warms up, the larvae resume
feeding and it is during this time (March and April) that they do the greatest
damage. The larvae become full grown in April and enter the ground for
pupation. Adults begin to appear in May and in years of abundance are often a
nuisance in dwellings and about lights durings most of June.
Adults have been seen at high altitudes in the Rocky Mountains during the
summer months. The moths reappear in September in greatly reduced numbers and
begin depositing their eggs. The pupa appears to be the overwintering stage.
A relatively few survivors are able to carry the species to big population
levels. This is due to their enormous reproductive capacities.
POTATOES
Colorado Potato Beetle
The Colorado potato beetle is one of the most commonly known insects in
the United States. Both the adult beetle and larvae feed on potatoes
devouring the foliage and terminal growth. Sometimes the injury is severe
enough to kill the plant.
The beetle is yellow with 10 black stripes extending lengthwise on the
wings. It is about 3/8 of an inch long and 1/4 of an inch wide. The beetles
come out of winter hibernation in the spring, mate and lay orange colored eggs
in clusters on the underside of the leaves. These eggs hatch in about a week
and produce humped reddish larvae which have 2 rows of black spots along the
sides of their bodies. They feed and become full grown in 2 or 3 weeks at
which time they are about 1/2 inch long. They then pupate in the soil. There
may be 2 generations a year under certain conditions.
Leafhoppers
While there may be more than one specie of leaf hoppers on potatoes, the
aster leafhopper is the most serious since it transmits the aster yellow virus
to potatoes as well as many other culivated plants. This leaf hopper is about
1/8 inch long, light green in color and is characterized by 6 tiny black spots
on the top of its head. It is a migratory species and usually begins to
increase in number in late June or July. Potatoes affected with aster yellow
are usually stunted, may show slender purple shoots and very often form aerial
tubers in the axils of the leaves. It overwinters in the adult stage in the
milder climates and when it becomes active in the spring, eggs are deposited
under the epidermis of the leaves. Within 2 weeks these eggs hatch producing
ligjit green nymphs which may be found feeding on the foliage. Both the nymphs
and adults are capable of transmitting the virus after the disease has
incubated in their bodies for at least 10 days. The njunphal period lasts from
2 to 4 weeks. There may be more than one generation,per year.
-------
- 30 -
SUGAR BEETS
Webworms
These worms are the most destructive leaf-feeding insects attacking sugar
beets. Both the alfalfa webworm and the beet webworm may be found on beets.
Their life history and habits are quite similar. Mature worms are about 1
inch long, green to nearly black in color, with light stripes on the back and
spots on the side of each segment. Heavy attacks while beet plants are small
may kill out entire stands. Attacks when beet plants are larger can cause
severe defoliations and losses in production.
As indicated in their name, these worms spin a small amount of webbing as
they feed on the plant. Many times the feeding begins in the central leaves.
When attacks are severe, more than 1 to 3 worms per plant will be found. In
large scale outbreaks, the worms move in large masses from field to field.
There can be 2 to 3 generations of worms per year. Signs of infestation
include webbing around the control of leaves at the base of the plants,
defoliation of the leaves or the presence of small, pearly white egg masses on
the leaves. Eggs are quite small, about the size of a pin head.
Beet Leafhoppers
This leaf hopper is commonly founa on beets in certain areas of the
country. Its potential for carrying a virus disease known as curly top makes
it a serious pest.
The beet leafhopper is a small, wedge-shaped insect, approximately 1/4
inch long when full grown and varies in color from light yellowish green to a
grayish brown. When they fly they appear white and have often been given the
name "white fly".
Beet leafhoppers breed in dry, desert areas of the West and southwest
feeding on many native plants. In spring, when rangeland weed hosts mature,
beet leafhoppers migrate with prevailing winds to other areas and will attack
growing beets. Only a small portion of the leafhoppers carry the virus. The
incidence of disease is dependent upon how soon leafhoppers have moved into a
field and how many of the leafhoppers are carrying the disease.
The eggs of the beet leafhopper are laid in the leaves of the beet plant
on which the adult feeds. Eggs hatch in a few days into tiny nymphs. The
nymphs feed and grow on the plants, eventually becoming adults in 3 to 8 weeks.
FRUITS
Codling Moth
The insect known as the codling moth has caused greater losses to apple
and pear growers than any other pest. It is found wherever apples and pears
are grown, producing the familiar "apple worm" found in the fruit.
-------
- 31 -
The codling moth spends the winter inside a silken cocoon on the tree or
almost anywhere in the orchard or packing shed area. The larvae are found
hibernating on wood, sacks, or corrugated paper and often in packing boxes,
posts, and trees. When warm spring days begin, the larvae transform into
pupae within the silken cocoon. By blossom time pupation is generally
complete. Typically, moth emergence occurs just at petal fall. The first
moths to emerge are males. The numbers of females progressively increases in
the next few days. If the weather is cool, adult emergence is prolonged and
may extend over a month. In warm spring weather peak emergence of the moths
will occur in less than a week. Cool weather retards egg deposition and has
the effect of spreading each generation through the season.
The codling moth egg is a white translucent circular disk appressed to the
leaf. It resembles the head of a pin that has been pushed through the leaf.
When numerous, the eggs are easily visible. Normally the egg hatches in 8 to
14 days. In the spring, all egg deposition is on the leaves but subsequent
summer generation egg deposition is largely on the fruit. The larvae may feed
on foliage when first hatched but they soon migrate to nearby apples and begin
to make entry. At this time the calyx end of the apple is a cup-like opening
which is a particularly favorable site for entry. Occasionally the stem end
of the apple will be entered. Generally the larvae reach maturity after about
3 weeks inside the apple. Then they emerge, either to migrate back to the
twigs or trunk or to drop to the ground and pupate. Twelve to 14 days are
required for the pupal stage at this time of the year and the second brood of
moths appear about the first of July. Forty-eight to 50 days are required to
complete a generation of the codling moth. The third brood generally appears
in mid-August. Third brood moths generally do not cause much damage but their
activity may interfere with pear and apple harvests.
When the first summer generation has been completed, only about 2/3 of the
moths emerge. About 1/3 enter the overwintering condition and emerge the
following year. Over half of the second summer generation enters the
overwintering condition and most or all of the third does so.
The codling moth is a small grey moth about 1/2 inch long with a chocolate
or bronze colored rounded spot at the apex of the wings. The grey appearance
of the rest of the body takes the form of undulating minute grey lines with
interspersed brown.
Two-Spotted Mite
The two-spotted mite overwinters primarily as an adult female in soil and
trash near the base of fruit trees. In general it is thought that any mites
on the trunk migrate down to emerging cover crop vegetation early in the
season. At this time mite populations exhibit a preference for herbaceous
plants and seem to attack fruit secondarily later in the summer. Since the
two-spotted mite spends half the growing season on the cover crop,
considerable control can be achieved through cultural practices such as fall
tilling, or destroying or spraying the weeds around the bases of the trees.
-------
- 32 -
The life cycle of the two-spotted mite, beginning with the egg hatch,
passes through three nymphal stages to the adult stage. The egg is spherical
and clear when deposited and is commonly found on the undersides of leaves.
Typically all stages are present at the same time. The immature larave is
six-legged and nearly colorless, gradually becoming pale green. The larave
molts into a protonymph which is somewhat larger, is pale green in color that
gradually darkens and has 4 pairs of legs. After another molt, the deutonymph
molts and becomes a mature adult.
At average temperatures, about 4 days are required to hatch the egg. In
the cool part of the season, 2 weeks or more may be required. The length of
the larval stage also varies with temperature and may range from 1 to 10
days. The length of the life cycle of mites varies from about 5 to 30 days.
Each adult female lays from 40 to 100 eggs. The adult life span may be up
to 2 months but averages 15 to 30 days. Unfertilized females produce young,
all of which are males. Under average growing conditions, probably 10
generations of mites are produced in a season. As temperatures become cooler
in the fall and the days shorter, the females turn orange and congregate in
crotches and under bark scales of the trunk and scaffold limbs. Clusters of
orange mites are often found in the calyx and/or stem end of apples at this
time of year. There is considerable mortality to the overwintering mites.-
The injury caused by mite populations is largely confined to foliage
feeding. This feeding causes collapse of plant cells and loss of vigor in the
tree. When infestations are heavy, the mite populations retard fruit color
development to such an extent that fruit quality may be downgraded. High mite
populations can also affect fruit bud formation.
CATTLE
House and Stable Flies
Stable flies and house flies look very much alike and have similar
habits. These two flies are primarily pests of animals around feedlots, yards
and pens. The stable fly looks much like the house fly except it has
piercing-sucking mouthparts and are vicious biters and blood suckers. House
flies do not feed upon the animals but they are extremely annoying. Both
flies breed in decaying organic materials. If animals use lots to water,
flies attack them and may return to the pastures with the cattle. Stable
flies rest on shady surfaces around barns, bunks, tanks or vegetation in the
vicinity of animal yards. House flies rest on sunny surfaces during the day,
roosting at night inside of barns and sheds (usually on ceilings).
Residual application to resting sites helps to control adults of both
flies. Stable and house flies have similar life cycles. Eggs are laid in
decaying organic matter and hatch in 1 to 3 days producing white maggots. The
maggots feed on the decaying organic matter such as manure and can complete
their growth in 6 to 7 days then turn into pupa. The pupal stage varies from
5 to 10 days on the average before adult flies emerge.
-------
- 33 -
Since both flies develop in manure, sanitation is a very essential part of
control. Elimination of natural breeding sites such as manure and water
soaked feeds and straw around premises is important. Stacking of manure will
help control flies in areas where it is not practical to remove the manure
immediately.
Treatment of animals, either with sprays or by dust bags and self treating
rubbers is not too effective for control of stable flies because these pests
feed primarily on the front legs of the animal. Treatment of animals for
house flies is quite temporary and it should be remembered that they do not
require feeding on the animals as do stable flies.
Baits containing approved insecticides are quite effective in controlling
numbers of adult house flies. Baits should be placed so that animals,
children and pets do not have access to them.
Cattle Scabies
Scabies is a microscopic mite that burrows in the skin where they produce
definite burrows in which the females deposit their eggs. These parasites
pierce the skin and suck lymph and epidermal cells. Their activities produce
a marked irritation which causes intense itching and scratching. The
resulting inflammation of the skin is accompanied by exudate which coagulates
and forms a yellowish crust on the skin surface. This skin area then becomes
thickened and wrinkled with a consequent loss of hair.
Spread of scabies among animals is rapid and is mainly by transfer of the
larvae nymphs and fertilized females from one animal to another. Scabies
falls under a Federal quarantine and infected and exposed animals must be
treated under the supervision of a Federal veterinarian. If the symptoms
described above are seen on cattle, the veterinarian in the area should be
notified so that diagnosis can be made and the infestation thus stopped as
soon as possible.
The insect pests described above are only a few of the the major pests
which can affect your farming or ranching operation. If you find an insect
which you cannot identify, contact your local county extension agent or
agricultural consultant. The various extension services have written
information on insect identification and treatment recommendations are
available. Remember to identify the pest properly before you use any
pesticide. Then only use a pesticide which is registered for that particular
use and follow the label directions for safe and proper use.
-------
- 34 -
Principles and Methods of Insect Control
Plant Insect Control
Present day insect problems, created or
aggravated by the concentration of host plants
(large areas with the same crop such as wheat
or corn) are diverse and without simple solutions.
Farmers and ranchers should follow the instruc-
tions and advice of competent fieldmen or consul-
tants in order to effectively cope with the wide
variety of pests found in modern agriculture.
Whether the farmer or a field consultant is responsible for conducting a
sound pest control program, a knowledge of insect identification, growth
patterns and development, and life cycles is necessary. Life cycle
information is essential in the timing of control measures. Only through a
thorough knowledge of a pest's life cycle can one hope to aim control measures
effectively at its most vulnerable stage of growth.
Crop value is an important consideration. Control of pest insects is
usually justifiable when the increase in marketable yield produced is worth
more than the cost of control. If the cost of controlling the pest is more
than the loss due to the pest, control measures may not be beneficial.
Preventative control measures can be used when you know through experience
that a certain pest or pests will develop to a damaging point in a given area
year after year. Some early treatments tend to control a pest before it ,has
reached its maximum rate of development and reproduction and before the crop
foliage has grown to the point where it is difficult to reach the pest with
sprays, granules or dusts. However, one should generally wait to treat with a
pesticide until the pest population is causing more damage than the cost of
treatment.
Outbreaks or epidemics of insect pests are usually caused by one or more
of the following:
a. large scale production of a single crop,
b. introduction of a pest into a favorable new area without Its natural
enemies,
c. weather conditions are favorable for rapid development and
reproduction of a pest. These conditions may also be unfavorable to
the pest's natural enemies,
d. use of insecticides which may kill the pest's natural enemies and
create conditions which may be favorable for the pest to multiply
unmolested or only partially controlled,
e. use of poor cultural practices which encourage pest infestations,
f. destruction of natural plant, animal and micro-organism communities
which otherwise provide normal control of insect population levels.
-------
- 35 -
There are a number of types of insect control procedures available. These
include: biological, mechanical, cultural, chemical, reproductive and legal.
Biological Control
Biological control can be defined as the
action of parasites, predators or pathogens
(disease producing organisms) on an insect pest
host or prey population which will reduce the
level of the pest below normal population
levels. Generally, biological control refers
to manipulations by man as distinguished from
natural enemies and natural control.
Biological control has a number of distinct advantages, three of which are
permanence, safety and economy. Once biological control is established, it is
relatively permanent and has no side effects such as toxicity, environmental
pollution or use hazards.
There are three kinds of traditional biological controls:
a. the introduction of exotic or foreign kinds of parasites,
b. conservation of parasites and predators,
c. augmentation of parasites and predators.
The use of insect pathogens such as fungi, bacteria and viruses is another
one of the techniques employed in the biological control of Insects.
Natural enemies should be able to play a role in most crop ecosystems.
One factor which may impede their effectiveness is climate. Other reasons
their activity may be inhibited include environmental factors such as dust,
competitors, drift of pesticides from adjoining fields or necessary pesticides
used on the crop.
Biological controls are not suitable in many pest situations. It takes
time for the parasites and/or predators to reproduce sufficiently to bring the
pest under control. A farmer often feels that he cannot wait for the natural
enemy to do the job because he needs a marketable crop each year. Other
technical difficulties involve such items as determination of which parasites
or predators to introduce, whether to use more than one parasitic species at a
time, how to eliminate secondary parasites that prey on the beneficial form
and whether a continuous program may be feasible. There is also the problem
of protecting such predators and/or parasites from pesticides.
Mechanical Control
Mechanical control is the reduction of Insect populations by means of
devices which affect them directly or which alter their physical environment
radically. These methods are often hard to distinguish from cultural
methods. However, mechanical controls involve special physical measures
rather than normal farm practices. They tend to require considerable time and
labor and often are impactical on a large scale.
-------
- 36 -
Hand picking, shingling and trapping are familiar mechanical methods of
insect control. Screens, barriers, sticky bands and shading devices represent
other mechanical methods of insect control.
Cultural Control
Cultural control is the reduction of insect
populations by the utilization of agricultural
practices. It has also been defined as "making
environments unfavorable for pests." Cultural
control usually involves certain changes in normal
farming practices rather than the addition of
special procedures.
Knowledge of the life history of a pest species is essential to the
effective use of cultural control methods. The principle of the "weakest
link" or most vulnerable part of the life cycle usually applies. The
environment is changed by altering farming practices at the correct time so as
to kill the pests or to slow down their multiplication. In this way, the
method is aimed more at prevention than at a cure.
Since cultural methods are usually economical, they are especially useful
against pests of low value (per unit) crops. Such methods are particularly
applicable to field crops.
Several methods of cultural control practices are:
Rotation - Certain kinds of crop rotation may aid in the control of
pests. Insects which are reduced effectively by rotations usually have a long
life cycle and a limited host range and are relatively immobile in some stage
of their development. Changing crops in a rotation system isolates such pests
from their food supply. Wireworms, white grubs and corn rootworms are good
examples. Your local extension service office may be able to provide you with
information on other pests and crops which could be used in a rotational
system.
Location - Careful choice of crops to be planted next to each other may
help reduce insect damage.
Trap Crop - Small plantings of a susceptible or preferred crop may be
established near a major crop to act as a "trap". After the pest insect has
been attracted to the trap crop, it is usually treated with insecticides,
plowed under or both.
Tillage - The use of tillage operations to reduce populations of soil
inhabiting insects may work in several ways: change physical condition of
soil, bury a stage of the pest, expose a stage of the pest, mechanically
damage some stage of the insect, eliminate host plants of the pest and hasten
growth or increase vigor of the crop.
-------
- 37 -
Clean Culture - Removal of crop residues, disposal of volunteer plants,
and burning of chaff stacks are measures commonly applied against vegetable
and field crops.
Timing - Changes in planting time or harvesting time are used to keep the
infesting stage of insects separated from the susceptible stage of the crop.
Resistant Plant Varieties - The sources of resistance to insects in crops
have been classified as non-preference, antibiosis and tolerance. Insect
preference for a certain host plant is related to color, light reflection,
physical structure of the surface and chemical stimuli such as taste and odor.
Antibiosis is defined as an adverse effect of the plant upon the insect.
This may be caused either by the deleterious effect of a specific chemical or
by the lack of a specific nutrient requirment.
Tolerance is the term applied to the general vigor of certain plants which
mey be able to withstand the attack of pests such as sucking Insects.
Tolerances also include the ability to repair tissues and recover from an
attack.
Advantages of the use of resistant varieties Include a cumulative and
persistent effect which often eliminates pest damage within a few seasons,
lack of dangers to man and domestic animals and low cost (once the program is
established).
Reproductive Control
Reproductive control is the reduction of insect populations by means of
physical treatments or substances which cause sterility, alter sexual behavior
or otherwise disrupt the normal reproduction of insects.
Chemical Control
Chemical control is the reduction of insect
populations or prevention of insect injury by the
use of chemicals to poison them, attract them .to
other devices or repel them from specified areas.
Chemicals are highly effective and economical and
can be applied quickly to have an immediate impact
on a pest population. When pest populations approach
economic levels and natural controls are inadequate,
pesticide applications maty be the only hope to save
the crop so that it can be marketed. It seems clear that pesticides must and
will continue to be used in a major way in integrated pest management programs.
At times pesticides are essential for:
a. the maintenance of adequate crop production,
b. the protection of forest resources,
c. the preservation of man's health and well being.
-------
- 38 -
n™ nf +hp advantaaes of the use of insecticides in many crop ecosystems
is that ^ than ^ajo? past may be controlled with a single application
I + L MDecially important as short term pest management tools. The
Pesticides are esp > pesticides be used when possible in a manner
that^T harmonious with other elements of the agro-ecosystem and augmenting
other control methods.
insecticides do have certain well know limitations which include:
i development in many areas of strains of pests that are resistant to
b. only'temporary control effects on insect populations often requiring
repeated treatments, u t j
c presence of residues of the pesticide in the harvested crop,
d outbreaks resulting from the destruction of their natural enemies,
p undesirable side effects on non-target organisms including: parasites,
' predators, fish, birds, and other wildlife, honey bees and other
necessary pollinators, man and his domestic animals and the crop plant,
f. direct hazards of the pesticide on the applicator and other persons in
or near the area of application.
Legal Control
Leqai control is the lawful regulation of areas to eradicate, prevent or
control infestation or reduce damage by insects. This involves mainly the use
of Quarantines and pest control procedures. Federal and state officials often
work with legally established local, community or county districts such as
weed districts or grasshopper control programs to control pests.
Integrated Pest Management (1PM)
IPM is the management of insect populations by the utilization of all
suitable techniques in a compatible manner so that damage is kept below
economic levels. It is an ecological approach that not only avoids economic
damage but also minimizes adverse effects to man and the environment.
Animal Insect Control
Control or management of insects
is an important component of the over-
all management program of the progres-
sive livestock producer. Insect control
or mangement is usually accomplished
through the use of (a) practices that
will avoid or reduce insect problems
and (b) the use of an insecticide that
will greatly reduce or eradicate a pest
problem. Non-chemical methods of control-
ling insects on animals are more limited
than with insect control on plants.
-------
- 39 -
Biological Control
Biological control of insects on animals follows the same basic concept as
using biological control in controlling plant insects. Parasites and
predators of insect pests may be used alone or in conjuction with the use of
other control methods.
Mechanical Control
Mechanical control involves special physical measures such as the use of
screens or barriers, use of pheromone traps or electric insect traps. Sticky
bands in animal pens are often used in controlling animal insect pests. One
of the major mechanical or cultural methods of controlling animal pests is
proper sanitation in and around animal pens. Poorly kept livestock areas tend
to be excellent breeding grounds for numerous animal pests. Good manure
management is a key to controlling livestock pests.
Chemical Control
Use of insecticides is the most common type of animal pest control.
Insecticides can be applied to animals safely if you observe the following
gu i de 1 i nes:
a. use the correct product,
b. apply the right amount,
c. apply it in the proper manner,
d. observe all associated safety procedures,
e. observe the proper time interval between application and slaughter or
freshing.
Safety precautions must be observed when applying pesticides to animals.
Some insecticides are readily absorbed into the milk but not necessarily into
the meat. Some products can therefore be used on beef animals but not on
milking dairy cattle.
Some insecticides are closely related to chemicals in medications. If you
or your veterinarian are treating an animal for a particular ailment and at
the same time you decide to treat the animal for lice, grubs, etc.; you may be
subjecting that animal to an abnormal amount of chemical. Be sure you know
what chemicals each of your animals has been exposed to. Recognize the fact
that some animals cannot be sprayed (i.e. horses), that others may react
adversely if treated at the wrong time (i.e. cattle treated for grubs) and
that some may inadvertently consune insecticides (i.e. thirsty animals may
drink insecticides, chickens may eat fly bait).
It is absolutely essential that all necessary precautions be taken to
ensure that an insecticide does not contaminate feed or drinking water. In
addition, be certain that run-off from animals does not drain into a river,
lake, pond or other water supply.
There are several methods of applying pesticides to animals and farm
buildings. These include: high pressure hydraulic sprayers, mist blowers,
self-treating oilers, dipping vats, dust bags and through feed and mineral
mixes.
-------
- 40 -
A high pressure hydraulic sprayer with a single outlet gun can be used to
spray large animals confined to a holding pen. Care must be taken to ensure
that all animals are thoroughly wetted. The high pressures provide the
penetration into fur and wool that is necessary for the control of lice, wool
maggots, etc.
When adjusted to lower pressures, a high pressure Sprayer can be used for
applying residual sprays to walls and other surfaces of farm buildings and
pens for fly control, etc. These sprayers usually have piston pumps and
mechanical agitators and are solidly built and durable.
Hand held electrically operated mist blowers and foggers are available and
are satisfactory for both space application of insecticides and for
application of sprays directly to the animal. They are primarily used for
louse and chorioptic mange (barn itch) control. There are also permanently
installed automatic mist blowers and foggers designed to spray animals as they
pass through an entrance or exit of a barn or corral. Care must be taken to
ensure that they are properly adjusted and calibrated and that the correct
formulation is used.
Self treating oilers and dust bags are popular ways of applying some kinds
of insecticides to cattle. Selection of the right product and proper
installation of the equipment are essential considerations. Pour-on and
spot-on treatments are used to control cattle grubs and to suppress louse
populations. It is important that you use the metering or measuring device
supplied with the product.
It is essential for all applications of insecticides to livestock that you
know the approximate weight of each animal to be treated. Some insecticides
can be administered through feed and mineral mixes. These should not be used
simultaneously. To be effective and safe, each animal must consume a precise
amount based on live weight each day. Is some cases, such as in a beef
feedlot, this can be easily done by knowing the amount of feed consumed daily
then blending in the required amount of Insecticide assuming each, animal will
eat the same quantity of feed. Difficulties arise when a farm has animals of
many different weights and in dairy operations where animals are fed different
amounts based on milk production. The farmer should ideally have different
blends for several groups of animals.
PLANTS
Unlike other agricultural pests, weeds don't
attack our crops or livestock directly. For that
very reason, losses due to weeds are less
noticeable and often more significant than losses
due to other pests.
The most common agricultural weeds are
species adapted to Invade and survive on
cultivated land. They grow where the natural
-------
- 41 -
vegetation has been disturbed. In a sense, they are dependent on our use and
manipulation of the land. Most have had a long association with man and many
of our most troublesome weeds were introduced into this country by early
settlers. They have had ample time to become quite adept at living in
man-made environments. Common weeds such as lambsquarter, pigweed, sheperd's
purse, bindweed and a host of others are "species of cultivation" that are
found worldwide in nearly all agricultural areas.
What is a weed? There is no single commonly accepted definition of a
weed. There is no listing that places desirable plants in one column and
weeds or undesirable plants in another. Although some species are normally
thought of as weeds, their designation as such ultimately depends upon where
they are growing. As an example, quackgrass is considered a weed in many
areas of the country. However, when it grows on a steep roadbank to help
prevent soil erosion it is not considered a weed. Generally though, weeds are
defined as plants growing where they are not wanted.
Why control weeds? Weeds can cause economic losses in a variety of ways.
Their most obvious effect on crops is a reduction in yield due to direct
competition for soil moisture, nutrients and light. Beyond this, weeds may
harbor pest insects, mites, vertebrates or disease agents. They can interfere
with the planting, transplanting, thinning, harvesting and processing of
crops. Some weeds may produce growth inhibitors which directly retard the
development of crop plants. Crop quality can be affected. For example, weed
seeds in cereal grains and in planting seed, can significantly reduce the
value of these commodities and weeds in feed may cause off-flavors in milk.
Still other weeds can be irritating or poisonous to man, livestock and
wildlife.
Green plants are basic for life and are indispensable in man's
environment. They are a complex life form that utilizes energy from the sun,
combined with minerals, water, and carbon dioxide to provide food for man and
wildlife, to beautify the landscape and to reduce soil erosion. Plants can be
classified in several ways. The most commonly used method is according to
life cycle. Weeds are classified as being annuals, biennials or perennials.
Weed Classifications
Annual Weeds - Annual weeds are those that live less than 12 months.
Summer annuals germinate from seed in the spring, flower and produce seed
during the summer and die in the summer or fall. They overwinter as seed and
are most serious as a pest in spring seeded crops. They are best controlled
in the seedling stage. Examples of summer annuals are: Russian thistle,
pigweed, lambsquarter and wild oats. Winter annuals germinate from seed in
the fall, overwinter as low-growing plants, flower -and produce seed the next
spring and then die. They are most serious in perennial crops such as
hayfields. They are easiest to control in the seedling stage. Shepherd's
purse and wild mustard are broadleaf winter annuals and downy bromegrass is a
grassy winter annual.
-------
- 42 -
Biennial Weeds - Biennial weeds live for two growing seasons. They
germinate from seed in spring or summer and produce, basal leaves and a fleshy
tap root. These basal leaves are referred to as a rosette and are found only
in biennial plants. Biennials overwinter in the rosette stage. The following
year they flower, produce seed and then die. They are most serious as weed
problems in pastures and hayfields and are best controlled during the first
year of growth. Typical biennials are common mullin, burdock and bull thistle.
Perennial Weeds - Perennial weeds live for more than two years and may
live almost indefinitely. While annuals and biennials reproduce only by seed,
perennials may reproduce either by seed or vegetatively and frequently have
stolons, rhizomes, spreading rootstocks, tubers and bulbs which may serve as
both survival and reproductive structures. Perennials emerge either in spring
or summer and don't normally flower during the first year. Their topgrowth
freezes back each winter and survival depends on underground structures.
Regrowth occurs the following year. Flowers and seeds are generally produced
during the second season and thereafter. Perennial weeds are the most
persistent and the most difficult to control.
Common Agricultural Weed Pests
Downy Brome
Downy brome, also called cheat grass, downy chess and wild oats, is a
winter annual that reproduces by seed. It germinates in the fall, lives over
winter and produces a seed crop the following spring or early summer.
However, it can also germinate in early spring if followed by frost and set
seed the same year. Germination of the seed is usually high but seed may
infest fields for several years because of undesirable germinating
conditions. The seed germinates under conditions of cool temperatures and
ample moisture. If soil moisture is adequate, it usually germinates in the
fall.
The plant grows 6 inches to 2 feet high. The sheaths and leaves are
covered with fine, soft hair. The head is branched and somewhat drooping.
Mature plants turn purple or brownish in color. The seeds are long and flat
with an awn about as long as the seed. It matures seed early, before most
other grass species or crops.
Downy bromegrass is troublesome in winter wheat areas, summer fallow and
on rangeland. The growth and spread of downy brome is encouraged by continous
winter wheat cropping and the so called trashy fallow system of farming.
Since downy brome and winter wheat are both winter annuals, downy brome is
especially hard to control where winter wheat is grown either continuously or
in alternate years without crop rotation. Also, the warm soil under trash
left by surface tillage favors germination of downy brome. Surface tillage
often does not disturb the soil enough to destroy this plant.
-------
- 43 -
There are a number of cultural ways to help control downy brome. These
include elimination of seed, tillage, crop rotation and mowing. Elimination
of seed can be partially accomplished by cleaning up field borders and between
small grain strips. Plants should be destroyed before they make mature seed.
Perennial, cool season grasses such as crested wheatgrass or Russian wildrye
can be planted in waste areas. All seed should be clean.
When tillage is used as a control measure, a good job should be done with
the first summer fallow operation. Weeds not killed at this time may develop
an extensive root system which may be difficult to kill later. The soil
should be dry enough to provide for good weed kill. Close mowing will prevent
seed production. Viable seeds will be produced if mowing is delayed more than
one week after heading. Generally two mowings about two weeks apart are
necessary. Waste areas can be burned.
Bull Thistle
Bull thistle is generally not a noxious weed and is not difficult to
control. However, it is often mistaken for Canada thistle which is a noxious
weed and at times very difficult to control. Bull thistle is a native of
Europe and has spread to most parts of the world. It has become a nuisance in
pastures, noncultivated fields, ditch banks and wasteland.
Bull thistle is a biennial plant which only reproduces by seed. It
produces a taproot and a rosette of spiny leaves the first year. The second
year it produces a stalk 2 to 5 feet high and very spiny leaves 3 to 6 inches
long, lobed, rough, hairy, deep green on the upper side and woolly white
underneath. The flower heads are 1 to 2 inches in diameter and nearly as
high, solitary on the ends of the branches, bright purple and fragrant. Bull
thistle is sometimes found in alfalfa, sweetclover and small grain seeds.
Most practices that will prevent seed production will control bull
thistle. The plants will not survive in cultivated areas. Mow second year
plants when the flowers are starting to appear. This will control the weed in
pastures.
Field Bindweed
Field bindweed usually grows in patches but can also infest entire
fields. The small, pink or white flowers vary in size up to 1 inch in
diameter. They close in the evening and during rainy weather. The leaves are
arrowhead shaped. Long, cord like roots grow out in all directions and form
buds which send up new shoots. The seeds are produced in round capsules.
They are about 1/5 of an inch long, dull black to dark brown, oval with one
face convex and the other angled with flat sides and coarse surfaces. The
seed may live in the soil for many years. Old patches should be watched for
new seedlings.
-------
- 44 -
Field bindweed is one of the most competitive of the perennial weeds.
Crop yields can be reduced 30 to 50 percent in bindweed infestations. A two
or three year food supply is stored in the extensive underground root system.
This makes it hard to kill by cultivation because the roots will live as long
as the food supply lasts. To control or eliminate field bindweed,
combinations of intensive cultivation, selective herbicides, soil sterilants
and competitive crops are usually more practical than the use of chemicals
alone.
Canada Thistle
The flowers of Canada thistle are small (3/4 inch or less in diameter) and
are light pink to rose purple in color. The leaves are dark green and very
crinkly. Sharp spines are numerous on the outer edges of the leaves and on
the branches and main stem of the plant. It is sometimes confused with some
of the common thistles. Most of these are biennials and much easier to
control. Bull thistle and several other common pasture thistles have a white
cotton like material on the leaves and stems. Canada thistle is usually dark
green but some varieties may be grayish-green.
Canada thistle emerges in April or May in most areas where it is found.
It is best adapted to areas where summer temperatures are moderate. It does
well in a wide variety of soils. Infestations are found not only in
cultivated fields but also in pastures, r angel and, forests, lawns, gardens and
wasteland. Because of its seeding habits, vigorous growth and extensive
underground root system, control or eradication is difficult.
Canada thistle is difficult to control once it becomes established.
Competitive crops such as alfalfa, winter wheat and seeded grass pastures
compete with Canada thistle but will probably not eliminate it. Increasing
seeding rates by one-half ana fertilizing at heavier than usual rates will
give thistles greater competition. Planting contaminated seed has helped
spread this weed, so be sure to always use clean seed.
One season of intensive cultivation from spring until freeze will usually
eliminate over 90 percent of Canada thistle. Cultivate every 14 to 21 days
using a sharp duckfoot cultivator with at least three-inch overlap of shovels
or blade type implement. Cut thistle plants no more than four inches below
the surface. Persistence and proper timing are important. Additional control
measures will most likely require the use of selective herbicides.
Wild Oats
Wild oat is an annual weed with growth habits similar to small grains. It
usually matures somewhat earlier than most small grains and shatters before
harvest. There are three major reasons why the wild oat plant is difficult to
control: 1) it shatters it's seed before most grain crops are harvested, 2)
the new seed crop has a high percentage of dormancy and 3) the seed is long
lived in the soil (seeds in the soil may emerge over a period of up to ten
years). Also, wild oat seeds are difficult to remove from small grain crop
seeds. Depending on the degree of infestation, wild oats will reduce yields
of wheat or barley up to 50 percent. A single wild oat plant can produce as
many as 800 seeds which can remain viable in the soil for ten years or longer.
-------
- 45 -
The use of weed-free seed, proper seedbed preparation, good crop rotations
and sound soil management practices are the most effective means of preventing
infestations of wild oats. Most wild oat infestations have started from
planting contaminated small grain seed.
Do not plow seeds under in the fall that have shattered from the current
crop. Wild oat seeds left in a field must go through an after-ripening period
before they will germinate. Many go through this period if left on the
topsoil through the winter but do not after-ripen if covered with soil in the
fall. Those seeds which after-ripen during the winter do not readily germinate
the next spring. This after-ripening period may vary from a few weeks to
several years.
Delayed spring seeding is probably the second most effective control
measure. Spring tillage before planting a spring crop kills many wild oat
seedlings. Harrow and pack the soil early in the spring to induce early
germination of wild oats.
Since wild oats and small grains have similar growth habits, a good
cultural control method is to include crops in the rotation that do not have
the same life cycle as the weed. Perennial forage crops, row crops and fall
seeded crops are useful in preventing infestations of wild oats.
Johnsongrass
Johnsongrass is a stout, persistent, perennial plant with creeping
rootstocks. It grows 3 to 10 feet tall, is smooth stemmed, erect and very
leafy. It is adaptable to a wide variety of soils but grows best in fertile
lowlands. Under certain conditions, Johnsongrass is poisonous to livestock.
Young plants are generally more toxic than mature ones. Interruption of
growth, as by frost or drought, tends to increase the poisonous properties of
the plant.
Johnsongrass can be eliminated from land only if reinfestation by seeds is
prevented. Until all grass plants are prevented from producing seed along
ditches, fence rows, stream channels, etc., control practices will need to be
repeated continually. Cultural methods of control usually are more practical
and less expensive than herbicides. Combinations of cultural and chemical
control methods have been used with success.
Cultural control will prevent Johnsongrass from spreading and will reduce
stands 90 percent or more. Objectives for controlling Johnsongrass should
be: 1) to weaken existing plants and kill their rhizomes (underground stems)
and prevent formation of new ones, 2) to control seedlings growing from seed
already in the soil, 3) to prevent seed production and 4) to plant noxious
weed-free seed or seed free of hybrids.
Close mowing or grazing for two seasons, followed by plowing, will weaken
Johnsongrass rhizomes and cause them to form near'the soil surface and be
relatively short and easier to kill with cultivation. The following season,
plow and cultivate every two or three weeks or whenever leaf growth reaches 2
-------
- 46 -
inches. Continue cultivation until freeze. Use an implement that will bring
the rhizomes to the soil surface where they will dry. A springtooth harrow
has been found more effective for this than a duckfoot or disk. It is best to
cultivate when drying conditions are favorable. Properly fertilized and
managed alfalfa provides good direct competition for stands of Johnsongrass.
But Johnsongrass must be weakened first before a stand of alfalfa can be
obtained.
Russian Knapweed
Russian knapweed is a perennial weed that is very difficult to control or
eradicate once it becomes established. In thick patches, no crop will grow in
competition with it. It will also invade native grass sods. Patches will
spread in alfalfa fields but more rapidly in cultivated fields. Russian
knapweed starts growth early in the spring. It normally emerges early in May
and is full grown (1 to 3 feet) by June. The stems and leaves are covered
with a short gray knap and have a very distinctive bitter taste.
Lavender-rose or white flowers about 1/2 inch in diameter appear during June.
They are similar to small thistle heads and are 3/8 to 1/2 inch in diameter.
The rootstock is dark brown or black, woody and scaly. Russian knapweed
spreads by underground root stocks and by seed.
Competitive crops are usually not effective for control of Russian
knapweed. If smother crops are used, they should be tall, have the capacity
to develop an early, dense spring growth and retain their vigor until frost.
Perennial grass crops offer some competition but need heavy fertilization.
One year of intensive cultivation, prior to seeding, will usually result in a
better stand of grass. Combinations of cultivation, cropping and selective
herbicides will reduce a stand 85 to 90 percent. The remaining 10 to 15
percent is difficult to kill.
Curly Dock
Curly dock, also called sour dock, curled dock and yellow dock, is a
perennial that reproduces by seeds and shoots from the crown. It is a common
weed in many areas, occurring mostly in low moist wastelands, hay meadows,
pastures and lawns. The plant has a large,, deep taproot which sends up a
flowering stalk 2 to 4 feet tall every year. 'During the first year, the plant
forms a dense rosette of leaves. After that it attains a height of 2 to 4
feet. The leaves are lance-shaped, bluish-green and prominently curly along
the margins. The blades are 3 to 10 inches long and the stalk of the leaf 1
to 2 inches long. Large numbers of reddish-brown winged pods are produced on
each plant. Usually three small, shiny, reddish-brown triangular seeds are
produced in each winged pod.
Curly dock is a bad pest in clover and alfalfa fields grown for seed. It
is difficult to separate from these crop seeds. In lawns and pastures, remove
scattered plants, including the roots, with a hoe or shovel. Badly infested
fields should be plowed and scattered plants should be mowed or plowed under
before they set seed. Curly dock can be eradicated with tillage or any
control method that prevents seed production.
-------
- 47 -
Principles and Methods of Weed Control
Effective control of an individual species is dictated by its growth
habits and reproduction methods. Stage of growth, soil type, climatic
conditions, crop and species of weeds are important factors which influence
control practices. Consideration of the location of the weed infestation such
as cropland, range land, orchards, wasteland or industrial site further
confounds the selection of proper control measures. Thus, it is important to
recognize that weed control is complex and that basic principles should be
utilized for maximum effectiveness in controlling weeds.
There are three basic methods of managing weeds: control, prevention and
eradication. Control is the process of containing, limiting and reducing weed
infestations, thereby minimizing the weeds competitive effect on a crop.
Control is also a method of decreasing the detrimental effects of weeds to
crops while considering the cost of the operation. The competitive damage to
crops caused by allowing a few weeds to escape may be economically justified
when considering the cost of obtaining complete eradication. The principle of
control usually pertains to annual weeds in farm crops.
Six principle methods of control are:
a. Mechanical
handpulling, hoeing and spading,
tillage (disturbing root systems),
mowing, and
smothering
b. Cropping and Competition,
c. Biological Control,
d. Crop Rotation,
e. Chemical, and
f. Fire,
searing,
flaming crops
Mechanical Control
Mechanical control involves the use of tools to physically cut off, cover,
or remove from the soil any plants that are not desired. Several methods are
available. Hand pulling, hoeing, and spading are laborious and inefficient
but effective methods of removing annual or biennial weeds. Most perennials
are not effectively controlled by this method since they are capable of
vegetative propagation from the root system.
Tillage with mechanical implements can be utilized in two ways: first it
is effective on small annual weeds as a means of severing or covering the
plants. When plants are larger, tillage effectiveness may be reduced.
Second, tillage can be used to disturb perennial root systems. Cutting and
disturbing the established roots can cause them -to desiccate before they
reestablish. However, multiple tillage operations are required to effectively
control perennial weeds.
-------
- 48 -
Mowing is a means of preventing seed production and reducing competition
from weeds. Mowing is ineffective on low-growing plants. Multiple mowing of
perennial weeds may serve to deplete the root reserves and result in the death
of the plants. Removal of the top of plants by mowing can result in
stimulating dormant buds which produce new stems.
Smothering can be accomplished by placing a barrier at the soil surface
that plants cannot penetrate. If plants are unable to emerge into the
sunlight, they will soon die from the lack of photosynthetic nutrition. This
method of weed control is often utilized in high value crops and in flower
gardens around the home.
Crop Competition
Crop competition as a method of weed control is based on the law of
nature, "survival of the fittest." Tlris is probably the cheapest and easiest
method of controlling weeds. A crop will survive and flourish if it can
compete more efficiently for sunlight, water, nutrients and space than the
unwanted plants. The growth habits of the crop in relation to the weeds are
important factors in developing a crop competition system. Early weed
competition is usually more detrimental to a crop than later competition when
the crop is well established.
Biological Control
Biological methods of control utilize natural predators of the undesirable
plants but are harmless to the desirable plants. Insects, diseases, parasitic
plants, selective grazing and competitive replacement plants are examples of
biological control agents. Natural enemies which attack the plant result in a
balance of nature which is a control program rather than a means of
eradicating a weed species. After the undesirable plant is removed, the
predator agent population decreases as a result of the elimination of the food
source. The weed species may increase again until the biological predator
population recovers sufficiently.
Climatic and environmental conditions are influential in the success of a
biological predator for controlling weeds. The ability of the insect or
organism to adapt to the environmental conditions of the host plant may be the
most important factor in the success of the biological control program.
Severe winters or prolonged drought may eliminate the predatory agent, whereas
the plant species you want to control may survive.
Crop Rotation
Crop rotation can be a means of controlling weeds by providing a strong
competitive crop on disturbed soil during all periods of a growing season.
Weeds can flourish prior to crop establishment and after harvest. Early
emerging crops can limit the growth of later germinating weeds. Farm managers
should provide crop cover on cultivated areas during as much of the growing
season as possible.
-------
- 49 -
Fire
Fire is an effective tool for removal of vegetation from ditchbanks, road
right-of-ways and waste areas. Intense heat can sear green vegetation which
usually dries sufficiently in 10 to 14 days so that complete buring can be
accomplished. Burning can kill small weed seeds on the soil surface and
emerging weed seedlings. Selective flaming in corn is an effective method of
controlling small annual weeds, but is less effective on perennial species.
Several treatments are required to control perennial species.
Chemical Control
Chemicals (pesticides) are the most modern and efficient means for
controlling unwanted plant species. Selective herbicides date back to the
turn of the century but the greatest advances have occurred in the last three
decades. It is important to realize that herbicides are a product of modern
technology and a tool for controlling weeds. The use of pesticides is not a
replacement for good management practices and conscientious farming.
Types of Herbicides
Selective Herbicides - Selective herbicides are chemicals which can remove
certain plant species with little or no damage to other species. Selectivity
is usually obtained as a result of the way the herbicide is used. The
selectivity of a chemical is not absolute and may depend on the following:
a. The amount of chemical applied,
b. The way it is applied,
c. The degree of wetting the foliage,
d. The precipitation following treatment,
e. The ability of a plant species to tolerate a specific herbicide, and
f. Differences in growth habits of crops and weeds.
Since selectivity of a herbicide can depend on all of the above factors, a
herbicide may be utilized as a selective or non-selective treatment depending
on intended use. Grass seedlings can be controlled by 2,4-0 although the
primary use of 2,4-D is the selective control of broad-leaved weeds in grass
crops.
Foliage treatments are herbicide applications to the leaves of growing
plants usually as sprays, mists or dusts. There are two basic types of
selective herbicides used in foliage treatments: contact and translocated.
Contact Herbicides - Contact herbicides are chemicals that do not
translocate or move in the plant. This group of herbicides kill only the
plants or portions of the plant actually contacted by the pesticide. In order
to obtain effective control, adequate distribution or coverage on the foliage
is essential. This can be accomplished by using high volumes of carrier or
diluent to apply the herbicide.
-------
- 50 -
Translocated Herbicides - Translocated herbicides are pesticides that move
within a plant once the material is absorbed into the tissue. The greatest
amount of transport is through the vascular system of the plant. Translocated
herbicides may be effective in destroying roots of perennial plants.
Soil treatments are herbicide applications to the soil. To be effective,
the herbicide must be carried into the soil by sprinkling or rainfall in order
to be absorbed by the root system of the plant. There are several types of
soil treatments: preplant, preemergence, and postemergence.
Preplant herbicide application is done prior to planting a crop.
Preemergence is application after planting the crop but prior to the crop or
weed emergence. Postemergence is application after both the crop and weed
have emerged. The type of soil application you should use will depend on the
crop being grown and the weed(s) you are trying to control. You should
consult your local extension service agent for advice on your specific needs.
Non-selective Herbicides - Nonselective herbicides are pesticides which
are toxic to all plants. They may be used to remove a wide range of
vegetation from an area. When no selectivity is intended, these compounds can
be utilized to control vegetation along fence rows, around pipe lines, traffic
signs, storage areas and parking lots.
As with selective herbicides, non-selective herbicides can be applied to
the foliage or soil. There are non-selective contact or translocated
herbicides used to treat the plant's foliage. Generally non-selective
herbicides applied to the soil include a wide variety of soil fumigants and
soil sterilants.
Soil Fumigants - Soil fumigants are non-selective compounds which vaporize
in the soil and kill seeds in the soil. They are relatively short-lived in
the soil and crops can be replanted within a month or less without toxic
effects. Vapam and methyl bromide are examples of soil fumigants.
Soil Sterilants - Soil sterilants are classified as: non-residual,
temporary, semi-permanent and permanent. Non-residual treatments kill all
green plant life and last for one or two days. Steam heat is the only
non-residual sterilant. Tempertures of 212® or greater for 30 minutes will
kill weed seeds and plant roots. Temporary sterilants kill all green plant
life but lasts four months or Iks. Semi-permanent treatment kills all green
plant life but persists for four months to two years. Permanent sterilants
kill all green plant life for more than two years.
The length of time the soil remains sterile depends on the following:
a. Classification of the sterilant,
b. Herbicide used,
c. Rainfall,
d. Application rates, and
e. Soil type and composition
-------
- 51 ¦
Prevention is the most practical method of controlling weeds. If no weeds
are allowed to infest a field, there is no problem with control measures.
However, the task of implementing an effective prevention program requires
extreme caution and alertness.
Rules of prevention weed control are:
a. Use clean seed,
b. Do not feed screenings, grain or hay containing weed seeds without
first destroying their viability by grinding, cooking or ensiling,
c. Do not use manure unless the viability of weed seeds has been
destroyed,
d. Do not permit livestock from weed infested areas to move directly to
clean areas,
e. Clean harvesters, cleaners, balers, disks, plows and other implements
before moving to other areas,
f. Avoid use of sand, gravel and soil from infested areas,
g. Nursery stock should be inspected for presence of weed seeds and
tubers and rhizomes of perennial weeds,
h. Keep banks of irrigation ditches free from weeds,
i. Keep fence corners, fence lines, roadsides and all other uncropped
areas weed free, and
j. Prevent the production of wind-borne weed seeds on any area.
Eradication is the complete elimination of all live plants, plant parts
and seeds of the target species from an area. True eradication may be
difficult since living plants and seeds (source for infestation) must be
exterminated. Eradication is justified under conditions where small areas are
infested with perennial weeds. Soil sterilization techniques can be used for
complete elimination of green plants.
Weed seed contamination of the soil makes eradication nearly impossible in
one season. Eradication programs should be designed to extend over several
growing seasons to assure that all germinating seeds and seedlings have been
killed. The development of selective herbicides in recent years has
facilitated eradication of some perennial species without denudina the area of
vegetation.
PLANT DISEASES
Plant disease agents have probably
had a greater influence on the course
of human history than any other of the
agricultural pests. For centuries living
organisms destroyed man's crops while
he remained ignorant of their very exist-
ence. As late as 1846, people were offer-
ing what in retrospect appear to be out-
landish explanations for the Irish potato
famine. It was not until the late 19th
century that any real understanding of
the nature and causes of plant disease
began to emerge.
-------
- 52 -
The living organisms that cause plant disease were difficult to
characterize simply because they are exceedingly small. Their discovery and
identification as disease agents awaited the invention of the microscope and
the development of modern scientific principles.
What is a plant disease? There are many definitions of a plant disease.
However, the most commonly accepted definition for a plant disease is any
harmful condition that makes a plant different from a normal plant in its
appearance or function. Plant diseases are divided into two groups:
non-parasitic and parasitic.
Non-parasitic plant diseases are caused by non-living agents. They cannot
be passed from one plant to another. Examples of non-parasitic plant diseases
include:
a. Nutrient deficiency,
b. Extreme cold or heat,
c. Toxic chemicals (air pollutants, salts, too much fertilizer),
d. Mechanical injury, and
e. Lack of or too much water.
Some non-parasitic plant diseases cannot be controlled very readily by
man. Examples are extreme heat or cold. However, many other non-parasitic
diseases such as nutrient deficiency, mechanical injury and too much
fertilizer can be controlled by the use of proper farm management practices.
Parasitic plant diseases are caused by living agents which live and feed
on or in the plant. They can be passed from one plant to another. The most
common causes of parasitic plant diseases are:
a. Fungi,
b. Bacteria,
c. Viruses, and
d. Nematodes.
Insects can be another cause. A few seed-producing plants and some
microbes can also cause plant diseases.
Three things are required before a parasitic disease can develop:
a. A susceptible host plant,
b. A parasitic agent, and
c. An environment favorable for parasite development.
Fungi are plants that lack green color (chlorophyll). They cannot make
their own food. There are more than 100,000 kinds of fungi. Not all are
harmful and many are helpful to man. Many are microscopic, but some, such as
the mushrooms, may become quite large. Most fungi reproduce by spores, which
function about the same way seeds do. Fungi may attack a plant both above and
below the ground. Fungal diseases include apple scab, anthracnose of beans,
smut in corn and powdery mildew on landscape plants.
-------
- 53 -
Bacteria are microscopic one celled plants. They usually reproduce by
simply dividing in half. Each half becomes a fully developed bacterium.
Bacteria can build up fast under ideal conditions. Some can divide every 30
minutes or so. Fireblight of pears, halo blight of beans and bacterial leaf
spot on peaches are caused by bacteria.
Viruses are so small that they cannot be seen with the unaided eye or even
with an ordinary microscope. They are generally recognized by their effects
on plants. Many viruses that cause plant disease are carried by insects.
Viruses are easily carried along in bulbs, roots, cuttings and seeds. Some
viruses are transmitted when machines or men touch healthy plants after
touching diseased plants. A few are transmitted in pollen. At least one
virus is transmitted by a fungus. A few are transmitted by nematodes. Wheat
streak mosaic and corn dwarf are diseases caused by viruses.
Nematodes are small, usually microscopic, roundworms. They are also
calle3 eelworms. Many nematodes are harmless. Others may attack crops
planted for food, fiber or landscape purposes. Some species attack the above
ground plant parts such as leaves, stems, and seeds. Most species feed on or
in the roots. They may feed in one location or they may constantly move
through the roots. Nematodes usually do not kill plants but reduce growth and
plant health. They may weaken the plant and make 1t susceptible to other
diseases.
All nematodes that are parasites on plants have a hollow feeding spear.
They use it to puncture plant cells and feed on the cell contents. Nematodes
may develop and feed either inside or outside of a plant. Their life cycle
includes an egg, four larval stages, and an adult. Most larvae look like
adults but are smaller. The females of some become fixed in the plant
tissue. Their bodies become swollen and rounded. The root knot nematode
deposits its eggs in a mass outside of its body. The cyst nematode keeps part
of its eggs inside its body after death. They may survive there for many
years.
Development of Plant Diseases
A parasitic disease depends on the life cycle of the parasite. The
environment affects this cycle greatly. Temperature and moisture are
especially important. They affect:
a. The activity of the parasite,
b. The ease with which a plant becomes diseased, and
c. The way the disease develops.
The disease process starts when the parasite arrives at a part of a plant
where infection can occur. This step is called inoculation. If environmental
conditions are good, the parasite will begin to develop. This stage before
injury develops is called incubation. If the parasite can get into the plant,
the stage called infection starts. The plant is diseased when it responds to
the parasite.
-------
- 54 -
The three main ways a plant responds are:
a. Overdevelopment of tissue, such as galls, swellings and leaf curls,
b. Underdevelopment of tissue, such as stunting, lack of chlorophyll and
incomplete development of organs, and
c. Death of tissue, such as blights, leaf spots, wilting or cankers.
Control of Plant Diseases
The ultimate concern about a plant disease is to reduce or eliminate the
economic or esthetic loss it causes. This is called the control of a
disease. Plant disease control involves one or more of three basic
principles: exclusion, protection and resistance.
Exclusion involves measures to prevent a disease organism from becoming
introduced into and established in an area where it does not naturally occur.
Plant quarantines are one means of exclusion.
Protection involves the use of plants that are not susceptible to the
disease. Immunity is the ultimate degree of resistance and is usually not
obtained in genetic programs aimed at developing resistance in a given plant.
The level of resistance may vary considerably depending on a large number of
factors, such as age of the host plant, aggressiveness of the pathogen,
relative favorability of the environment, etc. Very often a plant variety or
selection that is resistant to disease lacks desirable qualities wanted for
commercial purposes.
The two main ways of controlling plant diseases are the use of plants
which are resistant to various plant diseases and the use of pesticides.
Pesticides are designed to stop the growth of pathogens on or within host
plants and to protect healthy plants from pathogens that attempt to attack
them. However, pesticides used for plant disease control do not destroy the
pathogen, they only prohibit the disease from further attacking a plant.
VERTEBRATES
Agricultural problems with vertebrate
pests - rodents and those species
generally considered "wildlife" - rarely
approach the magnitude of the problems
caused by weeds, insects, diseases and
weather. Under certain circumstances,
however, and particularly for individual
growers, vertebrate pest problems can be
significant and difficult to deal with.
-------
- 55 -
There are a number of factors which complicate the control of vertebrate
problems. For example:
a. Mobility: Certain mammals and birds may come from long distances to
damage agricultural crops. Thus, they may spend most of their time on
private or public land where they are not a problem.
b. Unpredictability: There are many factors such as population density,
weather and availability of natural food which influence the transition of
a normally harmless vertebrate population into the role of a pest.
c. Public Perception: Most vertebrates, especially larger ones such as
geese or deer, are held in high esteem by the public. Efforts to control
them can then become a complex social problem as well.
d. Legal Status: Most mammals and birds enjoy seme protection under
state and/or Federal law as game animals, migratory birds or endangered
species. Only a relative few are unprotected or covered under "about to
damage" provisions. Thus a grower needs to be well aware of the species
involved in damage and the legal or permit requirements relative to it.
e. Control Techniques: Often because of environmental complications or
the legal status previously mentioned, broadcast chemical controls are not
as readily available for vertebrate problems as for weeds or insects.
Control may center on cultural practices or physical barriers.
Due to the many variables involved in controlling vertebrate pests, you
should contact your local county extension agent, state department of
agriculture or the U.S. Fish and Wildlife Service for specific recommendations
in identifying and controlling vertebrate pests in your area.
-------
- 56 -
APPLICATION
The choice of appropriate
application equipment and its
proper operation and mainten-
ance are perhaps as important
to effective pest control as
selection of the pesticide
itself. The substantial invest-
ment involved requires that the
choice be based on a thorough
familiarity with all alternatives, including the most recent developments in
application technology. Many problems of current concern are at least
partially solvable through the development of new application techniques and
equipment. When you choose application equipment, be sure that it is well
adapted for your purposes, that it is cost effective, that it has maximum
efficiency and that it will apply materials in an environmentally sound manner.
Before discussing specific types of application equipment, we need to
review briefly the various ways in which pesticides can be applied. The
particular method of application chosen depends on the nature and habits of
the target pest, the crop, the pesticide to be used, available application
equipment and the relative cost and efficiency of alternative methods.
Although there is frequently a choice between two or more methods, the method
of application is often predetermined by one or more of these factors. Always
bear in mind that your principal objective is to effectively bring the
pesticide into contact with the target organism.
Common methods of application of pesticides to crops are outlined below:
a. Foliar application is application of a pesticide to the aerial
portions of either a crop or a weed,
b. Soil application is application of a pesticide directly to the soil
rather than to a growing crop or weed,
c. Seed treatment is coverage of seed with an insecticide and/or
fungicide prior to planting,
d. Broadcast application is the uniform application of a pesticide to an
entire field or area. It can be either prior to or after emergence of the
crop,
e. Band application is the placement of a pesticide in a strip either
over or along the crop row. It may be made to the soil prior to crop
emergence or to crop and/or weed foliage,
f. Furrow application is the placement of an insecticide or fungicide in
a narrow line in the soil directly over the seed at planting time. Always
read the label to be certain that a furrow application is permissible.
Some insecticides in particular are toxic to seeds,
g. A split-boot application is the placement of a mixture of liquid
insecticide and liquid fertilizer in the soil to the side of the seed at
planting time. The mixture should be applied at least one inch on either
side of the seed and at the same depth,
CHAPTER 6
EQUIPMENT AND CALIBRATION
-------
- 57 -
h. Spot treatment is application of a pesticide to small discrete areas,
i. A directed-spray application is directed specifically at target weeds
in an effort to minimize contact with the crop,
*nc°fPOfatf°n 1s the use of tillage implements to mix the
pesticide with the soil,
k. Soil injection is application of a pesticide beneath the soil surface.
Types of Ground Application Equipment
Low Pressure Boom Sprayer
These sprayers are usually
mounted on tractors, trucks or
trailers. They are designed to be
driven over fields or large areas
of turf, applying the pesticides
in swaths to the crop. Low
pressure sprayers generally use a
relatively low volume of dilute
spray ranging from 10 to 40
pressure. They usually have roller
about 80 lbs./square inch. Handguns
gallons per acre applied at 30-60 lbs
type pumps that limit their Dressurp tn 1L ,
can be attached for remote spraying for snot ^„Abl-/tsqua"e 1"°hh- Handguns
infestations. ^ treatment and patches of weed
weight!anadapeted to^many^uses6 anT?^ cover* i^lative1^ inexpensive, light
usually low volume so that one tankful will cover ! large^are^^^' ^ ^
cover" dense^oliage b^ufe ^f "thei^lnw0^ cannot ade
-------
- 58 -
Advantages: High pressure sprayers are useful for many different pest
control jobs. They have enough pressure to drive a spray through heavy brush,
thick cow hair or to the tops of tall shade trees. -Because they are strongly
built, they are long lasting and dependable. Piston pumps are standard and
resist wear by gritty or abrasive materials. Mechanical agitators are also
standard and keep wettable powders well mixed in the tank. With a long hose
and handgun, trees, shrubs or other targets in hard to get at places can be
treated.
Disadvantages: High pressure sprayers are heavy and costly. They usually
use large amounts of water and thus require frequent filling.
Air Blast Sprayers
Practically all spraying in commercial
orchards and much of the spraying on shade
trees is with air blast sprayers. Air
blast sprayers are primarily designed to
carry pesticide/water mixtures under pres-
sure from a pump through a series of nozzles
into a blast of air that blows into the trees
by means of a fan. High volume fans supply the air which is directed to one
or both sides of the sprayer as it moves between rows of trees. Nozzles
operating at low, moderate or high pressure deliver the spray droplets into
the high velocity air stream. The high speed air aids in breaking up larger
droplets and transporting these smaller droplets for thorough coverage.
Agitation of the spray material in the tank is usually accomplished with a
mechanical agitator.
Advantages: A small amount of water covers a large area and very little
operating time is lost in refilling. They are usually less tiring to operate
than hydraulic sprayers and are particularly adapted to applying sprays over
a large area.
Disadvantages: Since the pesticide is carried by an air blast, these
types of equipment must operate under calm conditions. Windy conditions
interfere with the normal pattern of application of the blower. The sprayers
are normally large and can not get to a lot of hard to get at areas.
Granule Spreaders
Granular equipment is designed to apply coarse, dry particles that are
uniform in size to soil, water, and foliage. Spreaders may work in several
different ways including air blast, whirling disks, multiple gravity feed
outlets and soil injectors. They may be broadcast or band spreaders.
Advantages: Granular equipment 1s light, relatively simple and no water
is needed. Because granules are uniform in size, flow easily and are
relatively heavy, seeders and fertilizer spreaders can be used to apply
granules, often without any modifications.
-------
- 59 -
Disadvantages: Because granular materials do not generally stick well to
foliage, granule spreaders are not usually used on plants. Therefore the
applicator will need other types of application equipment for controlling most
leaf-feeding insects and most plant diseases.
Sprayer Components
Pumps
The ideal pump for sprayers should
deliver the recommended spray dosage at
the required pressure and should have
an economical service life.
Piston Pumps
Piston pumps are positive displacement pumps that can be used to apply
both corrosive and abrasive materials. There are two types: High
pressure-low volume-high speed and low pressure-high volume-low speed.
Gear Pumps
Gear pumps are semi-positive pumps that develop uniform, moderate
pressures but are limited in volume of output. They are not used with
abrasive materials.
Roller Impeller Pumps
Roller impeller pumps are adaptable to a wide range of pressures, volumes
and materials. This type is accurate in amount and placement of spray
material because it maintains constant pressure and flow.
Centrifugal Pumps
Centrifugal pumps are designed to handle abrasive and coarse materials.
Pumping action is accomplished by a high speed impeller that throws the
material out of the pump. It is used to spray high volumes at low pressures.
Tanks
Many spray materials are corrosive to metals and the resulting rust and
scale will plug the system's filters, cause excessive wear on the pump or clog
the nozzles. Tanks made of plastic-lined steel, stainless steel or fiberglass
are preferred materials because they are more durable and will be more
practical and economical over a long period of time. The inside corner
-------
- 60 -
The tank may be of any size but should be matched to the type of job the
sprayer will be expected to perform. The capacity will depend on the size of
pump used and the availability of the water for mixing. Commercially
available units generally hold 10 to 20 times the per minute output capacity
of the pump. (Example - 20 gallons per minute pump - 200 to 400 gallon tank)
Sprayer tanks should have a large, covered opening in the top fitted with
a removable strainer for ease of filling, inspection and cleaning. A drain
plug should be provided in the bottom to permit complete drainage when
cleaning.
Agitators
Make sure your sprayer has adequate
agitation or your actual pesticide
application rate may vary greatly as the
tank is emptied. By-pass agitation is
accomplished by pumping excess spray
material back into the tank under pressure.
Mechanical agitation utilizes paddles or
impellers. Jet agitation utilizes the spray
material from the system, pumped under
pressure through a jet nozzle. Mechanical agitation is the surest means of
getting good agitation but is expensive initially and harder to maintain.
By-pass agitation may be sufficient for solutions and emulsions but for
wettable powders a separate jet agitator should be used.
Nozzles
Nozzles used for a boom, hand-gun or broadcast type application control
the amount of pesticide applied, uniformity of application, thoroughness of
coverage and degree of safety. Nozzles should be selected to provide proper
droplet size and application rate within the required range of pressure.
There are five basic nozzle types:
Solid Stream
The solid stream nozzle is a type used in
hand-guns to spray a distant target and for
crack and crevice treatment in buildings.
Also a type used in a nozzle body to apply
pesticides in a narrow band or inject them
into the soil.
-------
- 61 -
Flat Fan
There are three types of flat fan nozzles:
The regular flat fan nozzle makes a narrow oval
pattern with lighter edges. It is used for
broadcast spraying. This pattern is designed
to be used on a boom and to be overlapped 30-50
percent for even distribution.
The even, flat fan nozzle makes a uniform
pattern across its width. It is used for
band spraying and for treating walls and other
surfaces.
The flooding nozzle makes a wide-angle spray pattern,
pressure thar. the other flat fan nozzles. Its pattern
across its width. It is used for broadcast spraying.
Hollow Cone
There are two types of hollow cone nozzles:
the core-disk and the whirl chamber. The pattern
is circular with tapered edges and little or no
spray in the center. It is used for spraying
foliage.
Solid Cone
This nozzle produces a circular pattern. The
spray is well distributed throughout the pattern.
It is used for spraying foliage.
Broadcast
This nozzle forms a wide flat fan pattern.
It is used on boom!ess sprayers and to extend
the effective swath when attached to the end
of a boom.
It works at lower
is fairly uniform
-------
- 62 -
Many spraying jobs can be done by more than one nozzle type of pattern.
Here are some general guidelines:
For Weed Control:
regular flat fan,
flooding fan,
even flat fan, and
hollow cone.
For Disease Control:
hollow cone, and
solid cone,
For Insect Control Outdoors:
regular flat fan,
hollow cone, and
solid cone.
For Insect Control Indoors:
even flat fan,
solid stream, and
atomizing.
To Minimize Drift:
flooding fan,
whirl chamber hollow cone, and
keep operating pressure below 30 psi.,
You can get nozzles in many materials. Here are the main features of each
kind:
Brass:
inexpensive,
wears quickly from abrasion, and
probably the best material for limited use.
Stainless Steel:
will not corrode,
resists abrasion, especially if it is hardened, and
expensive.
Plastic:
resists corrosion and abrasion, and
swells when exposed to some solvents.
Aluminum:
resists some corrosive materials, and
is easily corroded by some fertilizers.
Tungsten Carbide and Ceramic:
highly resistant to abrasion and corrosion, and
expensive.
-------
- 63 -
Keep nozzles in good working condition. For most boom applications,
select nozzles of uniform type and size. Nozzle caps should not be
overtightened. Adjust nozzle distance and spacing to suit the target. Follow
the nozzle instructions and the pesticide label. Allow for crop or weed
height if using water and a jar marked in ounces. Replace any nozzles having
faulty spray patterns. A good check is to spray on asphalt pavement. Watch
for streaks as you increase speed or as spray dries. Clean nozzles only with
a toothbrush and wooden toothpick. Any nozzle which shows a variation of more
than 5 percent from the average of all the nozzles should be changed.
Maintenance of Equipment
Periodic inspections and frequent lubrications
will reduce labor costs and breakdowns and prolong
the life of the pump and sprayer. Before using a
new sprayer or one that has been idle for awhile,
flush it with clean water. This will remove all
metallic chips sometimes found in new sprayers, and
rust and dirt from idle sprayers. Remove and clean
all screens and nozzles before spraying.
Use only clean water in your sprayer. The cleanest source is from a well
or city hydrant. Water from other sources should be filtered to help prevent
any damage to your equipment.
Sprayers should be thoroughly cleaned inside and out after each day's use
to prevent corrosion and accumulation of chemicals. The cleaning water should
not be discharged where it will contaminate water supplies, streams or crops,
or puddle to injure livestock, humans or wildlife. The strainers, screens and
nozzle tips should be periodically inspected and cleaned.
Cleaning equipment prior to storage at the end of the spray season is
important and should be done in the following manner:
Step 1: Hose down the inside of the tank completely, fill to half full
and flush the pumping system through the nozzles by operating the sprayer. Be
sure to dispose of your flushed material in a safe and proper manner.
Step 2: Repeat Step 1.
Step 3: Remove nozzle tips and screens. Clean them with a soft brush in
kerosene or a detergent/water mixture.
Step 4: Fill the tank half full and add one pound of detergent to every
50 gallons of water. Circulate the mixture through the by-pass pressure
regulator and jet agitator if used and then flush it out through the nozzles.
Step 5: Replace the screens and nozzle tips and refill the tank about
one-half full of water. Add one quart of household ammonia to each 25 gallons
of water. Circulate this mixture through the system for 5-10 minutes,
allowing some to go through the nozzles. Keep the remainder of the solution
in the system overnight and then run it out through the nozzles.
Step 6: Flush the system with the tank one-half foil of clean water by
spraying through the boom and nozzles.
-------
- 64 -
Step 7: Remove nozzle tips and disks, strainers and screens and store in
light oil. Store sprayer in a clean, dry structure. If the pump cannot be
drained completely, store it where it cannot freeze. Oil films should be
applied to some types of tanks and possibly to pumps to prevent rusting.
Check your equipment manual for specific instructions.
Calibration of Equipment
The are a number of variables affecting application rates: These include:
Speed - The speed a sprayer travels must be determined accurately and held
constant both when calibrating and actually applying the pesticide. Changing
the speed will change the output of the equipment. To determine the speed of
your sprayer, you should follow these steps:
Step 1: Set two markers in the field 88 feet apart (88 feet is 1/60 of a
mile),
Step 2: Select the gear and throttle setting on your equipment,
Step 3: From a running start, check the time in seconds required to drive
the 88 feet course, and
Step 4: Divide 60 by the time in seconds required to drive the 88 feet.
This will be your field speed. (Example: 15 seconds to drive 88 feet. 60
divided by 15 equals 4 miles per hour).
Pressure - The rate of flow of spray material relates directly to pressure
and should be held constant. Increasing the pressure increases the output
while less pressure decreases the output. To double the spray output, you
must increase the pressure four times. (Note: Applying pesticides at high
pressures produces smaller droplets, therefore, increasing the possibility of
drift).
Nozzle Openings - The nozzle opening determines rate of application when
pressure is held constant. The larger the opening, the greater the amount of
spray material applied. The shape of the opening determines the spray pattern.
Nozzle Spacing - Most sprayers have fixed nozzle spacing. If nozzles are
adjustable, moving them closer together will increase the amount of spray
applied per acre. Moving them further apart will decrease the amount
applied. Moving nozzles may also affect uniformity of the spray pattern.
The application of the right pesticide, at
the right time and at the proper rate is
important to prevent contamination of the
environment. To get the correct rate,
application equipment must be properly adjusted
and operated. Accurate calibration of the
equipment is important. Applying too little will
not control the pest and too much may injure the
crop being treated or damage the environment.
-------
- 65 -
Nozzle Wear - Sprayers cannot be accurately calibrated if nozzles are
worn. Abrasive solutions such as wettable powders can cause nozzles to wear
rapidly. Equipment should be calibrated more frequently when using wettable
powders.
Viscosity - Sprayers are usually calibrated with water. If the viscosity
of the spray material is considerably different than water, calibrate with the
liquid that will be used in spraying.
Pre-calibration Check
Several methods can be used satisfactorily to calibrate a sprayer. Select
the method that suits you best. Before calibrating, make the following
inspections:
a. Check the operating parts of your sprayer,
b. Be sure nozzle tips and screens are clean,
c. Be sure nozzle tips and screens are the correct size and shape for the
job, and
d. Check for nozzle wear by determining output of each nozzle.
Calibration Methods
Broadcast Spraying
a. Jar Method - Pre-calibrated jars may be obtained commercially. Lay
out a short, measured course, attach the jar under a nozzle and drive the
course at a certain speed and pressure. The application rate in gallons per
acre can be read directly from the jar.
b. Total Volume Method - After operating the sprayer to fill the supply
system up to the shut-off valve, fill the tank to the top . Select an area
for a test run that is similar to the area to be treated. Measure off 1/8 of
a mile (660 feet) and spray the test run at the speed and spray pressure that
will be used when spraying. Measure the amount of water (or spray solution)
used by refilling the tank to the starting level. The amount applied per acre
can be determined by multiplying the number of gallons used by the factor 66
and dividing by the width of the swath (boom). Example: Gallons used times
66 divided by swath width equals gallons applied per acre. (5 gallons (used)
times 66 divided by 20 feet (swath width) equals 16.5 gallons per acre.)
c. Nozzle Volume Method - Select a container calibrated in ounces or cups
or plastic bags to collect spray material from the nozzles. Fill the tank
one-half full or more with clean water and drive a measured distance (660
feet) by turning the sprayer on at the start and off at the finish.
Accurately measure the water collected from one nozzle or the average of
several nozzles and multiply by the number of nozzles on the boom for the
total volume or measure total discharge from all nozzles on the boom.
Calculate the number of gallons applied per acre by multiplying the number of
gallons used by the factor 66 and divide by the width of the swath (boom).
-------
- 66 -
Band Spraying
Band application where only a part of the total area is sprayed can be
determined by measuring off a distance (300 feet) and calculating how much is
used to spray this distance. Calculate the gallons per acre by the following
formula:
43.560 (Sq. Ft./Acre) X Gallons Used
Distance Traveled (Ft.) X Band Width (Ft.) X Nunber of Bands *
Example: 1/2 gallon of spray material was used to spray 300 feet using two
nozzles each spraying 12 inch bands.
43.560 Sq. Ft. X 0.5 Gal. Used . .
300 Ft. X 1 Ft. Bands) x 2 Bands a 36-3 Gals./Acre
Air Blast Spraying
Determine by trial the sp$ed that provides the best coverage of the
trees. The speed traveled in miles par hour can be determined by using a
watch with a second hand and by determining the number of tree spaces traveled
in a specific time. For example, if your tree spacing is 25 feet and you pass
7 tree spaces (175 feet) in one minute, you are traveling 2 miles per hour.
(175 feet in a minute X 60 minutes « 10,500 feet per hour.
10,500 feet divided by 5,280 feet per mile ¦ 2 miles per hour.)
Determine how much spray (gallons) you want to apply per tree, traveling
at two miles per hour. Make a trfal run with your equipment 1n operation with
determined nozzle rate, pressure and speed. Fill the tank with water and
spray a pre-determined number of trees. Measure the amount of water used and
determine the amount used per tree. By calculating the number of trees in one
acre you can determine the amount of spray volume used to cover one acre. Add
the amount of chemical recommended per acre to the volume of water used to
cover one acre of trees.
Granular Application
Granular applicators may be calibrated by collecting granules from one
delivery tube while covering a designated area. Use the same procedure as
under the nozzle volume method for total average coverage. If granules are
applied in bands, use the procedure designated under band spraying.
-------
- 67 -
Chemical Calculations
After calibrating the equipment to apply the
volume of spray desired to get good coverage,
you must determine how much chemical to put 1n
the tank to apply the correct dosage recommended
on the pesticide label. To do this you must know
the capacity of your tank and the recommended
rate per acre. Most recommendations are made
1n pounds of active ingredient per acre.
Liquid Formulations
Determine the number of acres that can be sprayed with one tankful. This
Is found by dividing the capacity of the tank (in gallons) by the gallons
applied per acre.
Example: Capacity of Tank - 200 Gallons
Volume of Spray Applied - 10 Gallons Per Acre
200 gallon tank divided by 10 gallons per acre equals 20 acres per tank.
Determine the amount of chemical to be added to the tank. This 1s found
by multiplying the acres one tank will spray by the recommended rate per acre.
Example: 20 Acres Per Tank At 1 Pound Per Acre Recommended
20 Acres X 1 Lb. Per Acre - 20 Lbs. Per Tank
If the recommended rate of chemical is given in pounds per acre, the
quantity of chemical (gallons per tank) can be determined by dividing the
pounds active Ingredient per tank by the pounds per gallon (concentration of
formulation).
Example: 20 Pounds Per Tank - 4 Pounds Per Gallon (Pesticide Concentration)
20 Lbs. Divided by 4 Lbs. Per Gallon » 5 Gallons Per Tank
Wettable Powders and Granules
These materials have active ingredients expressed as a percentage of the
total weight and may vary from 5% (Granular) to 80% (Wettable Powder) active
ingredient. To determine how much formulation (commercial product) you need
to apply to meet the recommended rate expressed in pounds of active ingredient
per acre, the following formula is used:
Herbicide (5% granular) at 2 lbs. per acre
2 lbs. per acre
.05 (5%) ¦ 40 lbs. per acre
Insecticide (80* W.P.) at 2 lbs. per acre
2 lbs, per acre
.80 (80%) ¦ 2.5 lbs. per Acre
-------
- 68 -
Solutions - Dilution by Parts
If a specific percentage solution is needed to treat a product or an area,
the following procedure should be used in determining how to mix for that
solution:
Dilution by Parts
Percent of pesticide concentration divided by solution required.
Example: 80% concentration (pesticide) - 5% solution required
80% divided by 5% = .80 divided by .05 = 16 parts finished product
16 parts = 1 part pesticide (80%) in 15 parts of water.
How many gallons of 50% pesticide must be added to 100 gallons of water to
make a 5% solution?
50% (.50) pesticide divided by 5% (.05) solution equals 10 parts total
finished product. Ten parts equals 1 part pesticide (50%) in 9 parts of water.
1 part pesticide = amount of pesticide required s 10 gals.
10 parts water 100 gallons water pesticide
-------
- 69 -
CHAPTER 7
APPLICATION OF PESTICIDES
Selection of Control Methods
The applicator must use every opportunity available to him to correctly
identify a pest before any control methods are considered. If he chooses to
use a pesticide, the identification of the pest is necessary to apply the
recommmended pesticide.
It is also important to know what stage of growth and time the pest can
best be controlled. Usually, a pest can be controlled best during one
particular stage of development. The applicator should know this stage so the
right kind of pesticide and proper formulation can be used to get the most
effect!ve control.
Is Control Necessary?
Control of a pest is not always necessary merely because damage shows up
on trees, shrubs or crops. The damage may not be caused by insects or a
disease. If an insect is present, it may be a beneficial species or, if it
did damage, it may have already left the area and will cause no further
damage. The damage also may have been caused late enough in the season so as
not to have any great effect on the crop. The economics of control also must
be considered.
Alternative Methods of Control
Must the control method be application of a pesticide? This question
should be considered by all applicators. Other controls such as cultivation
to control a weed, draining a breeding area to control mosquitoes, destroying
(burning) new plant growth to control diseases or the use of certain insect
species to control other insects are alternatives to the use of pesticides. A
pesticide treatment is not always necessary or economical.
Integrated Pest Management System (IPM)
Integrated control involves two or more methods used to control a given
pest. The important factor is to select the best combination of control
alternatives available and organize them into a pest management system.
Biological and chemical control methods have received the most attention in
integrated systems but other methods can also be used with success. Cultural
and physical-mechanical methods are also good tools to control pests.
Integrated management is an ecological approach to pest control. It
stresses the management of pest populations rather than eradication. Under
this system of control, it 1s recognized that crops can tolerate certain
levels of pest infestation. The Infestation must, however, be held within the
economic threshold or pest population that can be tolerated without incurring
economic loss.
-------
- 70 -
Selection of a Pesticide
If the applicator decides, after identifying the pest and considering all
available control methods, that a pesticide must be used to reduce the pest
population, the right pesticide must be chosen for the job. When choosing a
pesticide, an applicator must consider the following:
a. The pesticide's effectiveness against the pest,
b. Do the directions on the pesticide label meet the needs,
c. Will the pesticide be phytotoxic to the plants being treated,
d. What damage will the pesticide cause to non-target species, and
e. Is the equipment necessary to apply the pesticide available?
Mixing the Pesticide
Observe all safety instructions and mixing procedures. The applicator is
most likely to be dangerously exposed to pesticides when mixing since he is
handling the concentrated forms. It is especially important that all safety
precautions called for on the label be followed during mixing.
It is equally important that the applicator follow mixing procedures
listed on the label, especially when tank mixing two or more pesticides.
Partially fill the tank with the carrier being used before adding the
pesticide. Wettable powders should be mixed with water to form a slurry
before they are added to a spray tank. When mixing wettable powders and
emulsifiable concentrates, add the wettable powder in a slurry first. If a
compatability agent is used to help suspend the mixture, it should be added
before the pesticide.
Accessory Materials and Adjuvants
Pesticide action may be improved by addition of accessory materials and
adjuvants. Diluents and carriers change the volume of the pesticide
formulation. A solvent allows the pesticide to dissolve into a diluent or
carri er.
Carrier - Carriers are added to pesticide formulations that are
concentrated and not easily applied. It gives the formulation "body" and
"surface" adequate for ease of application.
Diluent - Diluents are added to a formulation when it is more concentrated
than the recommended application rate.
Solvent - Solvents are used when pesticide formulations are solid or
extremely thick liquid. Solvents dissolve the pesticide into the diluent or
carrier.
Adjuvants - Adjuvants are added to pesticide formulations to improve their
mode of action. These substances may increase spreading properties, assist
emulsification, increase toxicity, promote penetration of plant parts, reduce
interfacial tensions and perform other related functions. Adjuvants are
either incorporated into the pesticide formulation at the time of manufacture
or may be added by the applicator under certain conditions.
-------
- 71 -
There are three basic types of adjuvants:
a. Surfactants or Spreading Agents -r. These materials allow the pesticide
to spread out over treated surfaces and assist in wetting dusty, waxy or
greasy surfaces. These materials also reduce interfacial tension,
allowing the pesticide to make contact with a solid surface and improve
penetration of the chemical into plants or animals.
b. Emulsifiers or Emulsifying Agents - These agents are used to maintain
the stability (the time it stays mixed) of an emulsion. An emulsifier
couples oil and water together because it occupies the space between the
oil and water and allows them to remain mixed longer. Soaps and
detergents may serve as emulsifiers.
c. Sticking or Thickening Agents - Sticking agents help the pesticide
spray stick to surfaces such as leaves. Thickening agents increase
viscosity of the spray. They help spray stick to leaves and reduce
particle bounce and run-off during spraying. The term spreader-sticker is
commonly used.
Compatibility and Incompatibility of Pesticides
Application of one pesticide at a time has long been an established
agricultural practice. Today, because of the high cost of application,
pesticide applicators have begun mixing two or even several chemicals in their
spray tanks. This approach is an attempt to control more than one pest with a
single application. There are a number of problems associated with the mixing
of pesticides. Some chemicals are not compatible when mixed.
Adverse Chemical Reactions:
a. Toxicity or efficacy of one or both compounds may be reduced or
increased,
b. Precipitation may occur to clog screens and nozzles,
c. The phytotoxicity (plant injury) may increase, and
d. The total toxicity may be greater than the sum of the toxicity of each
pesticide (synergism).
Incompatibility:
a. Physical - Two or more chemicals mixed together may cause excessive
foaming, curdling or deposit of a gummy substance at the bottom of the
tank,
b. Phytotoxic - Chemical reaction of some mixtures may cause unexpected
injury to plants,
c. Placement - Mixing chemicals may alter their original formulation to
such an extent the proper placement is not possible,.
d. Timing - When applying a mixture of two or more chemicals, it may be
difficult to time the single application to the most susceptible stage
of each pest,
e. Water - Water is the most common carrier for pesticides. Water
hardness may alter the formulation to make application difficult or
less effective.
-------
- 72 -
Combination With Fertilizers
When mixing fertilizers with pesticides, problems may be experienced.
Mixing simple fertilizers such as superphosphate or phosphoric acid with
pesticides presents no real problems or incompatibility. Combining liquid
fertilizers and pesticides can become quite complicated and special care
should be taken when mixing them. The applicator should also make sure that
the pesticide(s) label(s) do not prohibit mixing with other pesticides or
fertilizers.
Synergism of Pesticides
Synergism is the property exhibited by some chemicals to greatly increase
toxicity and possibly increasing the toxic life of another compound when the
two are mixed together. When the total effect of two combined chemicals is
greater than the effect that would be realized by application of the compounds
separately, the result is called synergism. Synergism can greatly reduce the
cost of application by increasing the effectiveness of the treatment but it
may also increase the problem of toxicity to the applicator and non-target
species.
Applying Pesticides
Pesticides should be applied in a manner that gives the best possible
coverage with the least amount of drift. Correct selection of the application
method and equipment will eliminate many of the problems associated with
pesticide application.
Proper calibration of the equipment is necessary to ensure the correct
amount of pesticide applied to the treatment area. The equipment used will
depend on the pesticide formulation used or visa versa.
Timing and Frequency of Application
Proper timing of the application is extremely important for effective pest
control. Chemical treatment may have little or no effect if the insect, weed
or plant disease organism is not in the proper stage of development. Because
of problems related to residual life, sane pesticides cannot be applied more
than once during a season and must be applied so as not to leave a residue at
harvest time. Most pesticides have a waiting period for residue breakdown.
Effectiveness
Most pesticides on the market have a broad spectrum of control, meaning
they control a wide variety of insects, pathogens or weeds. The selection of
the pesticide that will most effectively control the pest with a minimum of
health, safety and environmental hazards will result in greater application
efficiency. The most effective pesticide is not always the least expensive or
the most toxic.
-------
- 73 -
Persistence
The ability of a chemical pesticide., to persist in the environment is a
prime consideration when selecting a pesticide. Persistence often is
desirable because the longer the compound remains active in the treatment area
the more effective and economical the control program. However, persistence
can cause serious environmental damage and greater risk to public health and
safety. Pesticides vary in persistence. Always select the one that will be
the least persistent and still be effective.
Pest Resistance
Chemical treatment of pest populations will destroy most of the
susceptible individuals leaving those that are resistant to the compound.
Because of their resistance to a specific pesticide, a different class of
chemical compound or another method of control must be used.
CIimati c Factors
a. Rainfall - Rainfall can have both detrimental and beneficial effects
on pesticide application. Detrimental effects include washing the
pesticide off of surfaces, diluting the pesticide, reducing its
effectiveness, excess soil leaching and increased potential of run-off
leading to surface or ground water contamination. Beneficial effects
include increased absorption of pesticide into plant or animal tissues,
moving herbicides into plant root zones, removing waxes and dust to
increase penetration and improving growth activity of plant for better
translocation of the pesticide.
b. Humidity - High relative humidity increases the rate of pesticide
absorption into plants and animals thus increasing its effectiveness. It
also can have detrimental effects on humans or valuable plants and animals
by increasing absorption.
c. Temperatures - High tempertures, associated with low relative
humidity, result in decreased pesticide absorption rates into plants.
High temperatures may result in increased absorption in animals. High
temperatures can cause increased volatility_in some pesticides, decreased
effectiveness, adversely affect some adjuvants and increase the
phytotoxicity.
d. Sunlight - Sunlight affects many pesticides by causing photochemical
breakdown. Some compounds such as carbamates break down readily, thus
reducing their effectiveness.
Drift
Pesticide drift has been identified as one of the principal concerns
facing agriculture. Where significant drift occurs, it can damage sensitive
crops, pose health hazards, contaminate soil and water in adjacent areas and
-------
- 74 -
cause considerable friction among neighbors. Although it is impossible to
eliminate drift entirely, it can be reduced to acceptable levels.
Drift can be defined simply as the movement of pesticides through the air
to non-target areas. There are two basic types of drift: particle and vapor.
Particle Drift - At the time of application, small spray droplets may be
carried by air movements from the application site to other areas. The
distance a particle of pesticide can drift is determined by one or more
factors: a) the wind speed, b) the distance from the spray nozzle to the
ground and c) the size of the particle itself. Normally only areas in the
immediate vicinity of the application site are affected by particle drift.
Vapor Drift - Vapor drift is the movement of a pesticide from the target
area as a vapor and results from the tendency of chemicals to volatilize.
Where vapor drift occurs, it may affect sensitive areas up to one mile or more
from the application site.
Aerial applications are particularly susceptible to drift since the
materials are released from greater heights and a greater percentage of
smaller droplets are formed than with ground equipment. Factors that
influence drift include particle size, specific gravity, evaporation rate,
height of release, air movements, weather conditions and the aerodynamic
forces created by the aircraft.
The rate of fall of particles through the air is affected by their size
and specific gravity. Small, lightweight particles fall very slowly and are,
therefore, more susceptible to drift. Oil droplets tend to drift farther than
water droplets because they are usually lighter and smaller and thus remain
airborne for a longer period. Using the same nozzles and the same spraying
pressure, smaller droplet sizes are produced with oils than with water. In
addition, the rate of evaporation of water based sprays 1s higher than that of
oil based sprays for equal size droplets unless antl-evaporant materials are
added to the formulation.
Weather conditions directly affect the direction, amount and distance of
drift. Avoid applications when the wind 1s bldwlng toward susceptible crops
or sensitive areas or when wind speed is in excess of limits stated on the
pesticide label. You may have to stop operations until conditions change.
Consult weather forcasts whenever possible. One danger is that unpredictable
changes in air movement may occur and carry the drift in an unexpected
direction.
During early morning and late evening, the difference in the air
temperature at ground level ano at some distance above ground is considerably
less than during the middle of the day. As the gound warms up, the air
temperature near the ground becomes significantly higher than the air above
it. This warmer air rises and may set up convection and thermal air currents
which lift small particles. These small ^particles may be carried some
distance before they settle out. For this reason and because wind speeds are
frequently lower, it is often better to apply pesticides either in the early
morning or in the evening.
-------
- 75 -
Calm conditions with a temperature inversion (ground air two to five
degrees cooler than the air above) may result in the smallest spray droplets
remaining suspended as a dense cloud tn a layer of undisturbed air. The
entire cloud may be moved out of the area before coming to rest and resulting
in relatvely high drift deposits. It is particularly important to avoid
aerial application when this condition exists. Sufficient turbulence should
be present in the atomsphere to disperse clouds of small drops when the spray
is applied.
Drift Control Measures
a. Use the lowest reasonable pressure,
b. Set the boom only as high as is needed for good coverage,
c. Leave an untreated border around the field,
d. Angle nozzles of ground sprayers slightly forward toward the ground in
the direction of travel,
e. Where practical, use a nozzle type which produces the largest droplets
at a given rate and pressure,
f. Use non-volatile or low-volatile formulations whenever possible,
g. Spray when wind speed is low,
h. Do not spray aerially during a temperature inversion,
i. Spray when adjacent susceptible vegetation is mature or not present,
and
j. Use a drift control agent such as foams, invert emulsions or
thickeners.
-------
- 76 -
CHAPTER 8
PESTICIDES AND THE ENVIRONMENT
The Agricultural Revolution upset in some measure the so-called "balance
of nature". With the cultivation of plants and the domestication of animals,
man first began to significantly alter the environment to meet his own needs
and objectives. Since that time, man's progress has depended largely on his
ability to successfully control and manipulate his environment and to adapt
its resources to his own ends. Man has succeeded in doing so with enormous
benefits to mankind.
During the twentieth century, the rate of progress has increased
tremendously. We have changed the world around us to a greater extent in the
last eight decades than we had done in all of our previous history. The rate
of change continues to increase today.
Until quite recently, we were able to ignore for the npst part the long
term consequences of our progress. Whatever harm we may have done to our
environment has been largely ignored, either out of ignorance or by choice.
We can no longer afford to be so naive. Changes now occur so rapidly and with
a potential for consequences so far reaching that they threaten to outrun our
ability to effectively deal with them or to examine their benefits and risks
in a rational manner.
A legitimate concern for our environment can no longer be limited to those
groups who have traditionally addressed environmental issues. We are all
beginning to reap the harvest of our largely unrestrained exploitation of the
world we live in. There is the potential for significant contamination of our
streams and groundwater, erosion of our topsoil Is Increasing in many areas,
and air pollution continues to be a serious problem 1n many areas. These are
some of the environmental problems facing us. We must all try to do our part
to help avoid contaminating the environment.
What is the Environment?
The environment is all of our pliysical,
chemical and biological surroundings such as
climate, soil, water, air and all species of
plants, animals and microorganisms. Until
just recently, most people viewed and studied
the components of the environment largely as
independent entities. Man obviously knew that
climate had an effect on the distribution of
species and that one organism could exert an
effect on another but we were unaware of the
complexity and extent of the Interrelationships
and balance that exists among all components of the environment. The branch
of science which studies these interrelationships is know as "ecology".
This manual is concerned with the effects of pesticides on the
environment. Pesticides are expressly designed to control those biological
components of the environment we consider pests. They have the potential,
however, to cause direct and immediate harm to living organisms other than
-------
- 77 -
those we wish to control as well as the potential for indirect or long term
adverse effects on other components of the environment.
The fate of a pesticide in the environment begins with its initial
distribution (application, disposal, spill, etc.) and continues through its
subsequent movement, persistence and fate in each component of the
environment. Studies have shown that a significant percentage of pesticides
never reach the intended site of application either because of drift,
volatility or misapplication. In a practical sense, it is impossible to
completely eliminate either particle drift or volatility but it is possible to
reduce them to acceptable levels. Where significant drift does occur, it can
damage sensitive crops, pose health hazards, contaminate soil and water in
adjacent areas ana cause considerable friction among neighbors. Drift of
insecticides and fungicides often goes undetected unless it occurs in
sufficient quantities that the actual drift is visible or it leaves a
noticeable residue. The effects of herbicide drift, on the other hand, are
often readily apparent. Substantial injury may occur to susceptible plants in
adjacent areas and perhaps even some distance from the application site.
Drift and ways to reduce it were discussed in the previous chapter.
Once a pesticide reaches the target area, subsequent movement may occur in
a variety of ways. It may volatilize from plant or soil surfaces, be moved by
wind or water from treated foliage to the soil, be carried laterally by
surface water runoff or through soil erosion, be incorporated into the soil
with crop residues, be taken from the field as residue on the crop itself or
be leached through the soil. Eventually, a large portion of the pesticides we
apply end up in the soil. Ultimately, various amounts may find their way into
surface waters or groundwater.
Many factors determine the extent of pollution which is likely to result
from the use of a given pesticide. The method of application, the
formulation, and the weather are important considerations. The properties of
the pesticide itself are equally important. Pesticides vary in their degree
of attachment or adsorption to soil particles. Those which are strongly
absorbed are less likely to be carried from the treated area by surface water
or leached through the soil into the groundwater. They may, however, be moved
readily by soil erosion. Pesticides also vary in their degree of water
solubility. Those with greater solubility have a greater potential for both
water contamination and movement. The volatility of a pesticide is a measure
of its tendency to turn into a vapor. Pesticides with greater volatility
dissipate more rapidly and pose less risks of soil and/or water pollution.
-------
- 78 -
An often critical factor in determining the extent of pollution is the
rate of degradation or breakdown of the pesticide. Pesticides vary
substantially in their susceptibility to degradation. Degradation may be
either chemical, physical or biological or any combination of the three. The
biological breakdown of a pesticide is the result of attack by fungi, bacteria
and other microorganisms. Biological activity in the soil requires adequate
soil moisture and temperature. The rate of degradation diminishes with
decreasing soil moisture and literally ceases in very dry soils. Breakdown
also decreases at lower temperatures and very little occurs during the cold
winter months.
When a pesticide is degraded, it is changed chemically. It is usually,
but not always, broken down into non-toxic compounds. For most pesticides,
once degradation has proceeded to a sufficient extent, they are no longer
active as pesticides and pose no further risks of pollution. While most
degradation of pesticides occurs in the soil, breakdown may also occur in
water or on soil or plant surfaces. All pesticides, including the chlorinated
hydrocarbons, are subject to degradation. Only the rate of degradation
varies. Although some pesticides may remain in the environment for years,
none will remain forever.
Man frequently refers to the persistence of a pesticide. Persistence is
simply a measure of how long a pesticide remains in an unaltered form at the
site of application or in the environment. Persistence at the site of
application is a function of a pesticide's adsorption, solubility, volatility
and susceptibility to degradation. In other words, a pesticide may persist
for only a short time at the site of application either because it is broken
down or because it is carried elsewhere. Persistence at the application site
may be either desirable or undesirable. Where the objective is long term
control, a persistent pesticide with residual activity may be desirable
whether it be applied to the foliage or the soil. Persistence and residual
activity are often used interchangeably. Persistence
beyond the time it is needed, however, is often undesir-
able and is usually referred to as residue. The residue
may be on the harvested crop or it may be in the soil
itself. Any type of residue can causie significant
problems. It may make the crop unacceptable for sale
or for use as feed or forage or carryover 1n the soil
may affect succeeding crops.
In addition to the properties of the pesticide itself, weather and the
rate of application can affect persistence at the site of application. Soil
moisture and temperature have important effects on degradation. In addition,
heavy rains or Improper irrigation may wash pesticides off foliage and may
cause excessive runoff and leaching. The rate of volatilization of a
pesticide is dependent to some extent on temperature and humidity. Soil type
may also be important. A clay soil normally adsorbs significantly greater
amounts of a pesticide than a sandy soil. Leaching of highly soluble
pesticides through the soil and into the groundwater can be a problem where
soils are particularly sandy.
-------
- 79 -
The persistence of a pesticide in the environment, rather than simply at
the site of application is largely a function of its susceptibility to
degradation. Its adsorption and solubility properties, as well as weather
conditions, do affect its rate of movement away from the application site and
its subsequent distribution. They also determine to some extent Its
availability for degradation. Ultimately it is the rate of breakdown which
determines its persistence.
Those pesticides which are persistent ms^y pose a greater risk of injury to
non-target organisms, particularly fish and wildlife which may be exposed when
the chemicals move out of treated areas. Some persistent pesticides are of
particular concern becaused they can accumulate 1n the bodies of animals.
This process is referred to as bioaccumulation or bi©concentration. Many of
the chlorinated hydrocarbons are both persistent and accumulative. These
combined properties account for most of the environmental problems associated
with their use.
Those pesticides which do accumulate 1n animal tissue may sometimes reach
harmful levels in the organism which was initially exposed to the pesticide.
More commonly, however, they remain below Injurious levels in the initially
exposed organism but become progressively more concentrated 1n the tissues of
animals higher up in the food chain. A food chain simply describes the
sequence whereby an animal feeds on a particular plant, animal or
microorganism and is in turn eaten by another animal and so forth until we
reach the animal at the top of the chain. At each succeeding level, an animal
normally eats a number of individuals from a lower Tevel of the food chain.
An accumulative pesticide can become increasingly concentrated as it moves up
the food chain. This process is referred to as b1omagn1f1cation.
Biomagnification can begin when an animal eats a treated plant or perhaps
more frequently when the chemical 1s absorbed from contaminated soil or
water. Biomagnification is of particular significance in aquatic food
chains. Man is not normally affected directly by this process simply because
he is usually protected by residue tolerances for the food products he
consumes. F1sh and wildlife have no such protection.
Pollution of the environment can occur not only as result of pesticide
applications but also as a result of spills and improper disposal of
pesticides and pesticide containers.
Effects On Non-target Organisms
The effects of pesticides on non-target
organisms may Involve direct and Immediate injury
or may be due to long term consequences of
environmental pollution. Pesticides m$y have an
adverse effect on such non-target organisms as
beneficial plants, bees and other beneficial
insects, on livestock and on fish and wildlife.
*L,
-------
- 80 -
Phototoxicity
Phytotoxicity is simply injury to plants due to exposure to a chemical.
Phytotoxic injury can occur on any part of a plant - roots, stems, leaves,
flowers or fruits. Nearly all pesticides can cause plant injury, particularly
if they are applied at too high a rate, at the wrong time or under unfavorable
environmental conditions. In some instances, inert ingredients (example:
organic solvents) can cause plant damage. However, most phytotoxic injury is
due to herbicides.
Herbicides may damage either the crop plants they are meant to protect or
crops or other plants on adjacent land. Some herbicides which are persistent
at the site of application may also injure succeeding crops. Injury to the
crop to which the herbicide is applied occurs most frequently when the
chemical has a narrow range of selectivity between the target weeds and the
crop being treated. Injury to succeeding crops is particularly common when
abnormally cold or dry weather inhibits degradation of the pesticide or when
rates of application were unusually high. Damage to crops or other plants in
adjacent areas is primarily due to drift or overspray, although it may
sometimes be a consequence of surface runoff.
Effects On Bees
Research to resolve the problem of bee
losses due to pesticides has been underway
since 1881 when damage to bees by lead arse
nate was first reported. A century later,
there is still no solution to this problem.
Modern agriculture is dependent on bees for
crop pollination. Unfortunately, in the United States a large number of bees
are killed each year by pesticides (principally insecticides). These losses
have a significant economic impact on beekeepers and farmers alike. Some
beekeepers are either being forced out of business entirely or are being
forced to move to other locations. Yields from crops that require bees for
pollination are frequently reduced.
Most pesticides, other than insecticides, are not hazardous to bees.
However, the most preferred insecticides in agriculture are generally very
toxic to bees. If an insecticide which is highly toxic comes in contact with
foraging bees, the bees will, in all probability, be killed. Bee kills
contained to a single field will most likely not have a large impact on the
health of a colony. However, if within a relatively short period of time,
similar kills occur in other fields visited by bees from the same colony,
there can be serious damage to the overall health of the hive. If the hive
itself is accidently sprayed or if it is located alongside a treated field,
bee kills may be substantial.
A more serious type of poisoning may occur if pollen becomes contaminated
with an insecticide. Bees will continue to forage for pollen 1n a routine
fashion even after plants have been treated. The pollen will be carried back
to the hive and be consumed by hive workers and often serious damage to the
hive results.
-------
- 81 -
The problem of bee losses due to pesticides is complex and no simple
solution appears to be in sight. Each individual must strive for a balance
between the use of pesticides and the protection of bees. Bee losses are
frequently due to the inappropriate or careless application of pesticides,
improper timing of application and improper disposal of unused materials.
While it is unlikely that bee losses can be totally avoided, they can
certainly be reduced with the safe and proper use of pesticides.
Growers and applicators should understand the foraging behavior of bees
before applying pesticides. Bees will forage in fields where crops and/or
weeds are in bloom. Application of pesticides to crops while they are in
bloom should be avoided whenever possible. Every attempt should be made to
eliminate weeds in bloom from areas to be sprayed. Applicators should also
avoid spraying ditch banks, fence rows and roadsides where plants are in bloom
and should keep in mind that drift onto these areas may also result in
substantial bees losses. Pesticides should also be applied in early morning
or in the evening when bees are not actively foraging.
Effects On Other Benefical Insects
The other major groups of beneficial insects are the predators and
parasites of agricultural pests. Despite the fact that they are valuable
allies in keeping pest populations below damaging levels, man often overlooks
them in his pest control programs. The loss of predators and parasites can
have unexpected consequences. In their absence, the population of the target
pest may rebound and may soon surpass pre-treatment levels simply because
there are no natural enemies to keep it in check. This is referred to as
resurgence of the pest population. In similar fashion, a pest which formerly
caused little damage because its numbers were held in check by predators and
parasites may suddenly begin causing significant damage, perhaps even greater
than that caused by the primary pest.
The ideal pesticide is one which selectively controls specific pests
without harming beneficial insects. Unfortunately, few such products have yet
been developed. The best alternative is to select and use pesticides in a
judicious manner and as part of a total pest control program.
Livestock Poisoning
The most important source, of livestock poisoning by pesticides is
contaminated feed or forage and contaminated drinking water. This
contamination is often caused by simple carelessness. Direct applications to
feed or forage crops may result in toxic residues if label directions for
grazing or feeding intervals are ignored or if the pesticide is applied
improperly. Drift and environmental pollution may also result in inadvertent
contamination of feed and forage and contamination of drinking water.
Poisoning can also result from improper application of chemicals used to
control pests of livestock. Poisoning of livestock.may cause illness or death
of the animal or, at lower levels of exposure, may result in contaminated milk
or meat.
-------
- 82 -
Damage to Fish and Wildlife
Damage to fish and wildlife may occur either
as a direct and immediate consequence of an im-
proper pesticide application (example direct fish
kills resulting from overspr«*y or drift into an
aquatic environment), as a result of contamina-
tion of wild plants used as a food source or as
a result of indirect pollution of fish and wildlife habitats, principally
through soil erosion, surface runoff and leaching. Except where direct kills
are concerned, pesticides with longer persistence are a significantly greater
hazard. Those which are both persistent and accumlative pose the greatest
risks.
Pesticides may either be lethal to fish and wildlife or, at sublethal
doses, may cause a variety of adverse effects including growth reduction,
behavioral changes and decreased reproduction. It is believed that sublethal
effects may be the most serious problem for wildlife. Many of the highly
publicized effects of the chlorinated hydrcarbons on wildlife, notably on
raptorial birds, have been related to reduced reproductive success.
Guidelines to Avoid Environmental Contamination
Use pesticides only when there 1s a definite need for pest control and
there are no feasible alternatives.
Be sure that you have a problem that pesticides can correct. Apply
them as a specific treatment not as a general remedy.
Use pesticides only on crops or animals that are being attacked by
pests and in a fashion which will help avoid bee kills.
Do not apply more pesticide than 1s needed. A thorough application at
the recommended rate is more effective, safer and economical than an
excessive amount applied in a haphazard manner.
The need to dispose of pesticides can be reduced by mixing only the
amount you need.
Do not drain surplus pesticides into sewage or septic tank systems.
Do not leave empty pesticide containers lying around. Empty
containers still contain small amounts o'f toxic chemical that can seep
into soil and water.
Follow all directions on the pesticide labeling.
Be aware of any and all consequences that may develop as a result of
an application of a pesticide.
a.
b.
c.
d.
e.
f.
9-
h.
i.
-------
- 83 -
TERMS USED IN PEST CONTROL
Abscission: The separation of fruit, leaves or stems from a plant.
Absorption: The process by which a chemical is taken into plants, animals or
minerals. Compare with adsorption.
Activator: A chemical added to a pesticide to increase its activity.
Adherence: Sticking to a surface.
Adjuvant: Inert ingredient added to a pesticide formulation to make it work
better.
Adsorption: The process by which chemicals are held on the surface of a
mineral or soil particle. Compare to absorption.
Adulterated: Any pesticide whose strength or purity falls below the quality
stated on its label. Also, a food, feed or product that contains illegal
pesticide residues.
Aerobic: Living in the presence of air. The opposite of anaerobic.
Aerosol: An extremely fine mist or fog consisting of solid or liquid
particles suspended in air. Also, certain formulations used to produce a
fine mist.
Agitation: The process of stirring or mixing in a sprayer.
Anaerobic: Living in the absence of air. The opposite of aerobic.
Antidote: A practical treatment for poisoning, including first aid.
Botanical Pesticide: A pesticide made from plants. Also called plant derived
pesticides.
Carcinogenic: Can cause cancer.
Carrier: The inert liquid or solid materia^ added to an active ingredient to
prepare a pesticide formulation.
Chemosterilant: A chemical that can prevent reproduction.
Chlorinated Hydrocarbon: A synthetic organic pesticide that contains
chlorine, carbon and hydrogen. Same as a organochlorine.
Chlorosis: The yellowing of a plant's green tissue.
Cholinesterase: A chemical catalyst (enzyme) found in animals that helps
regulate the activity of nerve impulses.
-------
- 84 -
Compatible: When two or more chemicals can be mixed without affecting each
other's properties, they are said to be compatible.
Concentration: The amount of active ingredient in a given volume or weight of
formul at ion.
Contaminate: To make impure or to pollute.
Corrosion: The process of wearing away by chemical means.
Deciduous Plants: Perennial plants that lose their leaves during the winter.
Deflocculating Agent: A material added to a suspension to prevent settling.
Degradation: The process by which a chemical is reduced to a less complex
form.
Dermal: Of the skin: through or by the skin.
Dermal Toxicity: Ability of a chemical to cause injury when absorbed through
the skin.
Diluent: Any liquid or solid material used to dilute or carry an active
ingredient.
Dilute: To make thinner by adding water, another liquid or solid.
Emulsifier: A chemical which aids in suspending one liquid in another.
Emulsion: A mixture in which one liquid is suspended as tiny drops in another
liquid such as oil in water.
Herbaceous Plant: A plant that does not develop woody tissue.
Immune: Not susceptible to a disease or poison.
Impermeable: Cannot be penetrated. Semi-permeable means that some substances
can pass through and others cannot.
LC50: The concentration of an active ingredient in air which is expected to
cause death in. 50 percent of the test animals so treated. A means of
expressing the toxicity of a compound present in air as dust, mist, gas or
vapor. It is generally expressed as micrograms per liter as a dust or
mist but in the case of a gas or vapor as parts per million (ppm)
LD50: The dose of an active ingredient taken by mouth or absorbed by the skin
which is expected to cause death in 50 percent of the test animals so
treated. If a chemical has an LD50 of 10 milligrams per kilogram (mg/kg)
it is more toxic than one having an LD50 of 100 mg/kg.
-------
- 85 -
Leaching: Movement of a substance downward or out of the soil as the result
of water movement.
Miscible Liquids: Two or more liquids that can be mixed and will remain mixed
under normal conditions.
Mutagenic: Can produce genetic change.
Necrosis: Localized death of living tissue such as the death of a certain
area of a leaf.
Necrotic: Showing varying degrees of dead areas or spots.
Noxious Weed: A plant defined as being especially undesirable or troublesome.
Oral: Of the mouth: through or by the mouth.
Oral Toxicity: Ability of a pesticide to cause injury when taken by mouth.
Organic Compounds: Chemicals that contain carbon.
Organophosphate: A synthetic organic pesticide containing carbon, hydrogen,
and phosphorus. Parathion and malathion are two examples.
Pathogen: Any micro-organism which can cause a disease. Most pathogens are
parasites but there are a few exceptions.
Phytotoxic: Harmful to plants.
Pollutant: An agent or chemical that makes something impure or dirty.
PPM: Parts per million. A way to express the concentration of chemicals in
foods, plants or animals. One part per million equals 1 pound in 500 tons.
Predator: An animal that destroys or eats other animals.
Propel!ant: Liquid in self pressurized pesticide products that forces the
active ingredient from the container.
Soil Sterilant: A chemical that prevents the growth of all plants and animals
in the soil. Soil sterilization may be temporary or permanent depending
on the chemical used.
Soluble: Will dissolve in a liquid.
Solution: Mixture of one or more substances in another in which all
ingredients are completely dissolved.
Solvent: A liquid which will dissolve a substance to form a solution.
Spreader: A chemical which increases the area that a given volume of liquid
will cover on a solid or on another liquid.
-------
- 86 -
Sticker: A material added to a pesticide to increase its adherence.
Surfactant: A chemical which increases the emulsifying, dispersing, spreading
and wetting properties of a pesticide.
Susceptible: Capable of being diseased or being poisoned by moderate amounts
of a pesticide.
Suspension: Finely divided solid particles mixed in a liquid.
Synergism: The joint action of two or more pesticides that is greater than
the sum of their activity when used alone.
Target Pest: The pest at which a particular pesticide or other control method
is directed.
Tolerance: a) The ability of a living thing to withstand adverse conditions
such as pest attacks, weather extremes or pesticides, b) The amount of
pesticide that may safely remain in or on raw farm products at the time of
sale.
Toxicant: A poisonous chemical.
Vector: A carrier such as an insect that transmits a pathogen.
Viscosity: A property of liquids that determines whether they flow readily.
Viscosity usually increases when temperature decreases.
Volatile: Evaporates at ordinary temperatures when exposed to air.
Wetting Agent: A chemical which causes a liquid to contact surfaces more
thoroughly.
-------
- 87 -
COMPARATIVE WEIGHTS, MEASURES, ABBREVIATIONS AND DILUTION TABLES
FLUID MEASURE
1/6 fluid ounce = 1 teaspoon (tsp.)
1/2 fluid ounce ¦ 1 tablespoon (tbs.) = 3 teaspoons
1 fluid ounce = 2 tablespoons = 1/8 cup
8 fluid ounces = 1 cup =1/2 pint
16 fluid ounces = 2 cups ¦ 1 pint
32 fluid ounces = 4 cups = l quart
128 fluid ounces = 16 cups = l gallon
AREA MEASURE
144 square inches = 1 square foot
9 square feet ¦ 1 square yard
30 1/4 square yards ¦ 1 square rod = 272 1/4 square feet
43,560 square feet ¦ 1 acre
4,840 square yards = 1 acre
160 square rods = 1 acre
640 acres ¦ 1 square mile
LINEAR MEASURE
1 inch = 2 1/2 centimeters = 25 1/2 millimeters
1 foot = 12 inches
1 yard * 3 feet
1 rod - 5 1/2 yards = 16 1/2 feet
1 mile ¦ 320 rods =1,760 yards ¦ 5,280 feet
WEIGHTS
1 ounce = 28 1/3 grams
1 pound = 16 ounces = 453 1/2 grams
2 1/5 pounds = 1 kilogram = 1,000 grams
1 ton = 2,000 pounds = 907 kilograms
ABBREVIATIONS
P.S.I. = pounds per square inch
G.P.M. = gallons per minute
6#P.A. - gallons per acre
R.P.M. = revolutions per minute
M.P.H. = miles per hour
in. = inches
ft. = feet
-------
- 88 -
MEASUREMENT CONVERSION FACTORS (APPROXIMATE)
Metric X Conversion Factor = Customary
LENGTH
mm
millimeters
0.04
inches
inches
cm
centimeters
0.4
inches
i nches
m
meters
3.3
feet
feet
m
meters
1.1
yards
yards
km
kilometers
0.6
miles
miles
AREA
cm3
m2
km2
ha
square centimeters
square meters
square kilometers
hectares (10,000 m2)
0.16 square inches
1.2 square yards
0.4 square miles
2.5 acres
in.2
mi
VOLUME
ml millimeters
1 liters
1 liters
1 liters
m3 cub i c meters
n)3 cubic meters
Customary
0.03 fluid ounces
2.1 pints
1.06 quarts
0.26 gallons
35.3 cubic feet
1.3 cubic yards
Conversion Factor
CENSTH
fl. oz.
pint
quart
gallon
ft .3
>ds.3
Metric
in. inches 2.54 centimeters cm
ft. feet 30.5 centimeters cm
yd. yards 0.9 meters m
mi. miles 1.6 kilometers km
AREA
in.2
ft. 2
yd.2
mi
a
square inches
6.5
square centimeters
square feet
0.09
square meters
square yards
0.8
square meters
square miles
2.6
square kilometers
acre
0.4
hectares
VOLUME
&
ha
tsp.
teaspoons
5.0
mi 11imeters
ml
tbsp.
tablespoons
15.0
millimeters
ml
fl. oz.
fluid ounces
30.0
mi 11imeters
ml
c.
cups
pints
0.24
liters
1
pt.
0.47
liters
1
qt.
quarts
0.95
liters
1
9a 1*
gallons
3.8
liters
1
ft.3
cubic feet
0.03
cubic meters
m3
yds.3
cubic yards
0.76
cubic meters
m3
h U.S. Government Printing Office 1984 - 681-055/458 Reg. 8
------- |