APPLY PESTICID
IIDE FOR COMMER
   U.S. ENVIRONMENTAL ...
      OFFICE OF PESTICIDE PROGRAMS
        WASHINGTON, D.C.  20460

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    TABLE  OF  CONTENTS
                                     Page
Acknowledgments  	    1
Preface 	    1
Introduction  	    2
Dispersal Equipment  	    2
Calibration 	    3
Pattern Testing  	    4
Operations 	    5
Protecting the Environment  	    6
Safety  Precautions  	    8
                 1976
                   i

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ACKNOWLEDGMENTS
PREFACE
This guide has been developed by North  Carolina
State University  under U.S.  Environmental Protec-
tion Agency (EPA) contract 68-01-2903. This con-
tract was issued by the Training Branch, Operations
Division, Office  of Pesticide Programs, EPA. The
leader  of this group  effort  was John H.  Wilson,
Jr., North Carolina State  University.  Editors were
Mary Ann Wamsley, EPA, and Donna M. Vermeire,
North  Carolina State  University.

Contributors were:
E. A.  Cancienne, Louisiana State University
Richard P. Cromwell, University of Florida
F. Farrell Higbee, National Agricultural  Aviation
  Association, Washington, D.C.
James  L. Maxwell, President, National Agricultural
  Aviation Association, Washington, D.C.
George F. Mitchell, Jr., M & M Air Service, Texas
Richard F. Moorer, U.S. Environmental Protection
  Agency
Frank  J. Murphey, University of Delaware
Richard  Reade,  Mid  Continent Aircraft Corpora-
  tion, Hayti, Missouri
Carrol M. Voss,  Ag-Rotors,  Incorporated, Gettys-
  burg, Pennsylvania
R. G.  Winterfeld, U.S. Department  of Agriculture,
  Agricultural Research Service, Yakima, Washing-
  ton
Wesley E. Yates, University of California
Federal regulations  establish  general  and specific
standards  that you must meet before you can use
certain pesticides. Your State will provide material
which you may study to help you meet the general
standards.

This guide  contains  basic  information for  aerial
applicators.  Other  guides are available to  help you
meet the specific national standards for commercial
applicators in various categories  of  pest  control.
Because the  guides were prepared to cover the entire
nation, some information  important to your State
may not be included. The State agency in charge of
your training can provide the other materials you
should study.

This guide will give you information about:
• dispersal equipment,
• calibration of liquid and dry systems,
• pattern  testing,
• operations, and
• environmental and safety  considerations.

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INTRODUCTION

Effective aerial application requires:
•  close cooperation between applicator and grower
   when planning a job,
•  consideration of the effects on  the  environment,
•  consideration for the  safety of people,  animals,
   and nontarget crops,
•  correct and well-maintained equipment,
•  accurate and uniform application,
•  a competent pilot, and
•  adherence to the planned procedure.

Limitations of aerial application  are:
•  need for correct weather  conditions,
•  difficulty in treating areas containing obstructions,
•  difficulty in treating  small  or  irregularly shaped
   areas, and
•  long ferrying distances.


DISPERSAL EQUIPMENT

Both fixed and rotary  wing  aircraft  are  used  for
aerial  application. Metering  and dispersal  equip-
ment on the  aircraft must meter  correct quantities
of pesticide  formulations  and  deliver them  uni-
formly. The equipment must be accurate so  it can be
calibrated  correctly.


LIQUID  SYSTEMS

Liquid dispersal systems consist of:
   tank,
   agitation system,
   pump,
   piping  and fittings,
   filters (screens),
   boom,  and
   nozzles.

These systems may be wind-driven or they may be
hydraulic  or  mechanical, powered by the aircraft
engine.

Tank—The  tank  should be  leakproof and corro-
sion-resistant.  It  should have  a mechanism  for
emptying the  contents quickly in case of emergency.
The aircraft  must have a guage that measures tank
contents.  The tank should  be fitted with  an  air
vent—:a tube  type or a spring-loaded  flapper valve.
Agitation System—Most pesticide formulations re-
quire some form of agitation during  application.

Pump—The  pump system must be  able to deliver
'large quantities  of liquid material  per  unit of time.
Wind-driven  pumps must have a workable brake.

Piping and Fittings—Main piping and fittings should
have  a large diameter (approximately  2 inches)  in
order to apply high volumes of liquids, and a smaller
diameter (approximately 1 inch) for low-volume ap-
plication.  Smaller piping is  adequate on helicopters
because of their slower application speed.

Filters—Correctly  sized line filters  and nozzle filters
(screens) will prevent nozzle clogging. Screen sizes
range  from  20 to  100  mesh, according  to the
size  of the  nozzle opening (larger  mesh (20) for
larger nozzles).  Screens should be located between
the tank and pump or between the  pump and the
boom.

Boom—The boom supports and supplies the nozzles.
When the  boom is located near the trailing edge
of the wing,  clearance between  control surfaces  of
the wing and the  boom is  essential. End caps on
the boom  make it easier  to  flush the  boom  and
nozzles. The  boom should have a positive shut-off
valve.

Nozzles—Special nozzles  are  available for  use  in
aircraft systems. They must be equipped with an
antisiphon  or nondrip  check valve.  Manufacturer's
specifications will guide  you  in  your  choice.  A
uniform  spray  pattern depends on  correct nozzle
placement on the boom.

The spray pattern shifts in the direction of propeller
rotation. Adjusting the distance between the nozzles
on the boom helps to correct this problem (see illus-
tration  below).  Placing  end  nozzles inboard  will
prevent the wingtip vortex from trapping fine drop-
lets, causing uneven distribution and drift.
       Front View of Variable Distance Nozzle Placement

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Nozzle  placement on a helicopter  boom may be
uniform except where the spray may hit parts of
the aircraft such as the skids. A rear section boom
is sometimes used to help keep spray off the heli-
copter.  The angle of the nozzle in  relation  to  the
direction of travel affects droplet size (see illustra-
tions below). Flight speed also has  an effect on  the
size of  droplets.
     This nozzle position
        produces
      coarse droplets
This nozzle position
   produces
  tine droplets
      This nozzle position
         produces
       medium droplets
    Not this
  (spray collects
   on structure)
                     An adjustable  gate is frequently  used to regulate
                     flow rate. It must have a tight seal when closed.
                     Check the gate often to be sure it is set correctly
                     and is not leaking.
                     CALIBRATION

                     Calibration is adjusting  your equipment to apply
                     the desired rate of pesticide. Calibration is especially
                     important in aerial  application,  since large areas
                     are covered  in  a short time.  Calibrate often to be
                     sure  that the equipment  is adjusted correctly.
LIQUID SYSTEMS

Here are the basic steps in sprayer calibration:
• Determine the acres your aircraft's system treats
  per minute at the speed and height you plan to fly.
• Figure the gallons you must  spray per minute to
  apply the recommended rate.
• Select the  size and number of nozzle tips which
  will  deliver the  correct number of  gallons per
  minute at the operating pressure of your system.
  Use  the nozzle manufacturer's specifications as a
  guide.
• Make a trial run.
• Determine the amount of chemical to add to the
  tank.
ULV  SYSTEMS

Ultra low volume (ULV) spraying requires a special
liquid dispersal  system.  Manufacturers can supply
specifications for ULV systems. Few pesticides are
labeled for ultra low volume aerial application.
DRY SYSTEMS

These systems may be used for applying dry formu-
lations  such as  dusts,  granules, and baits.  The
application equipment and the size,  shape, density,
and flowability of the materials affect swath width
and  pattern. The hopper must  have walls  steep
enough to  ensure uninterrupted  flow, and  have a
lid that will close tightly. An agitator will keep fine
materials from bridging.  The  air vent  should be
either a spring-loaded  flapper  valve  or  tube type.
                     The following example will explain these basic steps.
                     Your  aircraft has a 300 gallon tank. The  effective
                     swath  width is 50 feet.  You plan to spray at  100
                     mph at  a  height of 8-10 feet.  The  chemical is to
                     be applied at the  rate of 1  pint per 3  gallons of
                     spray  per  acre.  The  operating pressure will be 40
                     psi.

                     • Determine acres per minute covered.
                       Acres per minute=

                       2 X swath  width (ft.)X speed  (mph)
                       In our example,
                1,000
                 2X50X100
                     1,000
= 10 acres per minute
                     The  table below will  tell you  the acres covered
                     per minute  when  swath width  and aircraft speed
                     are known.

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Acres Per  Minute for Various  Speeds and  Swath
                     Widths
   Determine the amount of chemical to add to  the
   tank.
Speed
(mph)
40
50
60
70
80
90
100
110
120
Swath Width (Feet)
30
2.4
3.0
3.6
4.2
4.8
5.4
6.0
6.6
7.2
35
2.8
3.5
4.2
4.9
5.6
6.3
7.0
7.7
8.4
40
3.2
4.0
4.8
5.6
6.4
7.2
8.0
8.8
9.6
45 50 75 100 200
3.6 4.0 6.0 8.0 16.0
4.5 5.0 7.5 10.0 20.0
5.4 6.0 9.0 12.0 24.0
6.3 7.0 10.5 14.0 28.0
7.2 8.0 12.0 16.0 32.0
8.1 9.0 13.5 18.0 36.0
9.0 10.0 15.0 20.0 40.0
9.9 11.0 16.5 22.0 44.0
10.8 12.0 18.0 24.0 48.0
                                                    Chemical per tank = acres per tank X chemical
                                                                               recommended per acre
   Determine gallons per  minute (gpm) required.
   In our example, 3x10 = 30 gallons per  minute.
   Be sure your pump can deliver this volume.
   Select the nozzles.
   First determine the gpm per nozzle that would
   deliver the  required 30 gpm  flow.  Most agri-
   cultural aircraft booms  can accommodate  aboul
   40 nozzles, but most applicators prefer to use the
   smallest number that will provide a uniform pat-
   tern. Let's assume you  choose to  use 26  nozzles.
   The gpm per nozzle is  determined this way:
                      gpm required
   gpm per nozzle=—	
                    number of  nozzles
                    30
   In our example,  —=1.16 gpm  per  nozzle
                    26
   You chose a pressure of 40 psi. Using the manu-
   facturer's catalog,  select a  nozzle delivering 1.16
   gpm at 40  psi.  You may find  that  the nozzle
   closest to your needs   delivers  only  1.10 gpm.
   This small difference can be adjusted  by  increas-
   ing the pressure.
  • Make a trial run  to check the system.
   After installing 26 of the selected nozzles, make
   a trial calibration test  flight  to be sure  you are
   spraying at  the correct  rate.

   Fill the tanks with water to a known level on a
   level apron or strip. Fly  the aircraft at the selected
   100 mph  air speed and at the selected  pressure
   for a timed  period (60  seconds in this example).
   Bring  the aircraft back to the same  point  and
   measure the amount of  water needed  to refill the
   tank to the  original mark.  Divide the number of
   gallons used by the number of acres  (10 in  this
   example)  treated  to determine  the  gallons  you
   are spraying per  acre.
                                                    Acres per tank =


                                                    In our example,
                gallons per tank
                gallons per acre
                300 gallons  per tank
                  3 gallons per acre
                               100 acres per tank
100  acres  per tank XI  pint  per  acre =100  pints
                          (12.5 gallons) per tank

DRY  SYSTEMS

Make several test flights  with  the spreader installed
to determine the quantity of  material metered out
for a given gate setting.  Helicopters may use elec-
tric or hydraulic air blowers  and  the  material can
be caught  and measured while  running  up on the
ground.  You should use inert (blank) granules of
the same size and density as those in  the formula-
tion  to  be applied.  Operate the  spreader  for  a
measured  period  of  time (at  least  30 seconds).
Weigh the  quantity needed  to refill  the hopper.
It may  take three or more  trial  gate  settings to
determine the one that will give the required dis-
charge in  pounds  per minute  of granular material.
To find the pounds per  acre  being applied,  divide
the pounds  per minute by the acres per minute.

PATTERN  TESTING

Check the  swath pattern to make sure the distribu-
tion across the swath  is as  uniform as possible.
Both helicopters and fixed-wing  aircraft create wind
currents (vortices) that affect the swath pattern. The
tests  must  duplicate the airspeed,  height of flight,
spray pressure, and nozzle angle and placement or
gate settings that will be used for the actual appli-
cation. Make pattern tests in. calm air (winds less
than  3  mph)  to  avoid  distortion caused by cross-
winds. The best way to test a liquid  pattern is to
add  a tracer  (dye or fluorescent  material)  to the
water in the tank(s) of the aircraft. For dry pattern
testing,  use a blank (nontoxic) material  with prop-
erties similar to the formulation to  be  applied. Col-
lect  the test material on paper (for  liquids)  or in
buckets (for dry materials) placed  across the flight
path  on the ground. Observation  of  the  collected
materials will show the actual swath pattern.

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A rectangular pattern  gives perfect  distribution if
flight  swaths  are spaced perfectly. The  trapezoidal
and tsiangular patterns  are better, however, because
they allow for some error in spacing swaths. They
give uniform  distribution across the field except for
the first and  last swaths.

                  Ideal Swath Patterns

       I             III      II
I'll!
1
jjjjj

Rectangular
pattern


^







~~i r~
n


~i
gives perfect but is poor
distribution with

with perfect imperfect

~\ /
Trapezoidal
pattern


^ 	 "


/
spac
~x;;
:ing
~_-*<~
s
V
pacing,
^

\
also gives perfect and less
distribution variation
with perfect with

spacing imperfect
~~~- ^
Triangular
pattern
,-'•


S
pacinc
J.
^^
also gives perfect and less
distribution variation
with perfect with
spacing imperfect
spacing.
OPERATIONS

GENERAL

When an aircraft has been calibrated, the  airspeed,
spraying pressure (or gate  setting for dry materials),
height of flight, and effective swath width are fixed.
Applications must be made at the same settings.

PRESSURE

Pressure should  be around 40-50 psi (pounds  per
square inch). Choose the  pressure near this range
that  will combine with your  selected swath width,
airspeed, and  nozzle type to give the correct rate
of application and desired droplet size.  With most
nozzle  types, droplet size  decreases as pump pres-
sure increases.  Use  pressure  gauges  to  indicate
boom or pump  pressure.

FIELD  FLIGHT PATTERNS

For rectangular fields, fly back and forth across the
field in  parallel  lines.  Flying  parallel  to  the  long
axis of the field will reduce the number of turns. For
pilot safety, start treatment on the downwind side
of the field if there are low-speed crosswinds.  This
prevents  flying through the previous  swath.  (See
diagram below.) To prevent skips  and drift,  stop
flying if wind speed increases excessively.

                             Wind
                            Direction
If the area is too rugged or steep  for this pattern,
flight lines should follow the contours of the slopes.
When the area is too steep  for contour work,  make
all applications  downslope.

SWATH MARKING

Swaths  can  be  marked with  permanent or  semi-
permanent flags  set  above the height of the crop to
guide  the pilot.  This method is  useful if the field
will be treated several times a season.

Two flagmen can help the pilot line up on the field.
When the pilot has lined up on his swath, the nearer
flagman starts pacing off (or counting crop rows) to
the next swath. Flagmen should avoid being directly
sprayed on,  and  they should never turn their  backs
toward  an oncoming aircraft.  When the aircraft is
being flown parallel to a row crop, one flagman can
identify the swath row for the pilot.

Automatic flagmen  are often used. These  devices,
attached to the aircraft and controlled by the pilot,
release weighted streamers.  The  streamers give the
pilot a  visible mark  to help  him  judge  the next
swath.  Helicopters on small field applications may
not need flagmen.  Their  short  turnarounds  allow
them to locate the next swath easily.

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TURNAROUND
At the end of each swath, the pilot should shut off
the dispersal equipment and pull up out of the field
before beginning his turn. Complete the turn soon
enough to permit slight  course corrections  before
dropping into the field again for the next s\vath. (See
diagram below.)
                                                                    Strong downwash
                                                                    and vortices area
                                                                             Shut off here
               Proper Turnaround
 Wind
Direction
                                                            Strong downwash
                                                            and vortices area
                                                                                  -*-Wind—
                                                                                Start here
                                                                             Wind —
                                                                                    Shut off here
OBSTRUCTIONS
                                                                 -Wind —
                                                             Adjust distance to compensate for drift
If there are obstructions  (trees,  power  and tele-
phone lines, or buildings)  outside  the  field  at  the
beginning or end of the swath, turn the equipment
on late or shut it off early.  When the field is com-
pleted, fly one  or two swaths crosswise (parallel to
the obstruction) to  complete the job.

Obstructions inside  the  field  should be treated in
the same way. Skip the area around the obstruction
and spot treat it later.

Areas next to buildings, residences, livestock, non-
target crops, or waterways  should  be treated with
caution:
•  Fly parallel to the sensitive area.
•  Leave a   border  of  untreated  crop  to  avoid
   possible drift onto the area.
•  Avoid making  turns over dwellings  where pos-
   sible.
                                               PROTECTING  THE
                                               ENVIRONMENT

                                               CONTROLLING DRIFT

                                               Drift  is the airborne  movement of spray, granule,
                                               or dust particles to  places other than  the target
                                               area.  Properly controlled .drift may help  the pesti-
                                               cide  reach the  target.  Drift  is  harmful  when  it
                                               causes damage in nontarget areas.

                                               The  main factors that must be  considered in con-
                                               trolling drift are discussed below.

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Droplet Size
                           Weather
Droplet size  is one of the most important  factors
affecting drift.  Small droplets  are  a much  greater
drift hazard than large droplets. They stay in the air
longer because they fall more  slowly, and they are
more easily carried by wind currents because they
are lighter.

Pesticide  spray systems  cannot produce  a com-
pletely uniform droplet size. Rather, they produce a
range of droplet sizes.

Nozzle  type and pressure  are important factors af-
fecting  droplet size. In general, the size of  droplets
decreases as the  size  of  the  nozzle  opening  de-
creases  or the pressure increases.


The position of nozzles on the  boom also affects
droplet  size.  (See equipment section.)
You can get chemical adjuvants  which affect drop-
let  size:
• Thickening agents may be added to  spray mix-
  tures to create larger  spray particles. However,
  the airstream may break these large droplets into
  smaller ones.
• Surfactants are sometimes  added  to  spray  solu-
  tions to create smaller droplets, improve coverage,
  and increase wettability of the  spray. Be sure that
  droplets are not so  small that they create a drift
  problem.


A measurement of nozzle performance is  the Volume
Median Diameter (VMD) of the droplets  it produces.
The VMD is the droplet diameter that  satisfies the
condition that half of the spray  volume consists of
drops larger, and half consists of  drops smaller.


  Drift Distance of a  2.8% Oil/Water Emulsion
 Applied During Strong Temperature Inversion at
   Boom Height of  5  Feet and Wind Speed Less
                   Than 5 mph.
  Final VMD
 (micrometers)
     400
     200
     100
      50
Distance Downwind
       (feet)
    50
   150
   400
 1320 (V4 mile)
                           A pesticide applicator is concerned mainly with the
                           weather in  the  immediate  area  of application and
                           less than 1,000 feet from the ground.  The weather
                           in  this small  area has  a  major effect on  the  pesti-
                           cide  application,  including  the  chance  for  drift
                           problems. Wind is an important weather  factor af-
                           fecting drift. Stop at once  if wind increases  exces-
                           sively during  application.
                           Other  important  factors  are
                           "lapse".  These  terms  refer  to
                           change from  the ground upward.
                                "inversion"  and
                                the  temperature
                           An inversion layer exists in still air that:
                           • is  coolest at the  ground level,
                           • gets warmer up to a certain height, and
                           • gets cooler from  that point on up.

                           Particles released into the cool air layer at ground
                           level during an inversion have a minimum  upward
                           movement.  The  slightest air movement can cause
                           this mass  of particles  to drift for great distances
                           before they fall.

                           A lapse exists when the air:
                           • is  warmest at ground level, and
                           • gets continuously cooler at higher  elevations.

                           During a strong lapse, the warm air near the ground
                           rises, carrying very  small pesticide particles with it.
                           An applicator should at least be aware of these two
                           conditions,  because sometimes they  can be severe
                           enough to cause serious drift problems.
                           Vaporization
Another type of pesticide movement is called vapor-
ization (vapor drift)—the  volatilization of an active
ingredient  during  or after  application. You  must
know which pesticides are highly volatile (evaporates
easily).  High  temperatures  or other  climatic con-
ditions may cause vaporization of some active  in-
gredients. Apply them  during  periods of relatively
low temperature and high humidity. Use" active  in-
gredients  with  low  volatility  where  vaporization
might cause problems.

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Protecting Bees

Honey bees  and  other  beneficial  insects  can  be
harmed by some pesticide applications. Beekeepers,
aerial applicators,  and their customers must coop-
erate  closely  to protect honeybees. You can reduce
bee losses significantly by careful planning and good
communications. Bees travel for long distances, so
use of pesticides toxic to bees  may affect hives out-
side the  immediate vicinity of the  treatment area.
When using  materials hazardous to  bees,  remind
your customer to notify the beekeeper so that he may
protect his bees. With few exceptions, dusts may be
more hazardous to bees than sprays. Time of appli-
cation is important and depends on blooming period
and attractiveness of the  crop. Treatment during
the night  and early morning before  bees  are  forag-
ing are the saf-est for the bees.


SAFETY PRECAUTIONS

GENERAL PRECAUTIONS

• Wear  protective  clothing and equipment appro-
   priate for  the pesticide. The label on each pesti-
   cide specifies the protection  required.
• Know the  pesticide being applied and how to get
   emergency help if needed.
• Avoid all unnecessary contact with spray or dust.
• Change clothing and bathe after each day's work.

PILOT

• Avoid loading or handling highly  hazardous pesti-
   cides.  Exposure  to toxic pesticides  could cause
   illness that would make it unsafe to operate the
   aircraft.

   The  signs  and symptoms  of  illness  commonly
   include dizziness and constriction of the pupils of
   the eyes (myosis).  Myosis  impairs visual  sharp-
   ness and can lead  to  fatal  accidents. Direct  eye
   contamination  by organophosphate or carbamate
  pesticides may cause constriction of the pupils for
  up to 7 to 10 days without any other symptoms. A
  pilot who has experienced any symptoms of pesti-
  cide poisoning should not fly until he has had
  medical clearance.
• Make  preflight aircraft check.
• Check  operation  and  calibration of  dispersal
  equipment periodically.
• Check target area and surroundings for safety  or
  drift hazards before application.
• Avoid flying through drift.
• Do not apply pesticides over  flagmen or other
  persons.  Use  of  permanent  markers  and auto-
  matic  flagmen eliminates the possibility of harm
  to flagmen.
• See that members of the ground crew know their
  responsibilities and are acquainted with label pre-
  cautions.
• Do not fly in a manner or at a time  which may
  create  a hazard—even if  customer insists.
• Warn  all  people in  the treatment area about the
  application.


GROUND CREW

• Close  tanks and hoppers tightly after filling.
• Remove  any spilled  chemical.
• Clean  aircraft, especially the cockpit, frequently.
• Where  possible,  clean  equipment on a  hard-
  surfaced  apron so that runoff can be collected
  and disposed of  safely.
• Do not stand in  runoff water without  appropriate
  protection or allow  it to  splash on you.


FLAGMEN

• Warn  all  people in  the treatment area about  the
  application.
• When  the aircraft is lined up  for a  pass, move
  over to the next position.
• Do not turn your back on an approaching aircraft.
• Stay at the field until the pilot has completed the
  job so you can help if an accident occurs.

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