APPLY PESTICIDES CORRECTLY
  A GUIDE FOR COMMERCIAL APPLICATORS

FOREST PEST  CONTROL
          ..VIRONMENTAL PROTECTION AGENCY
          OFFICE OF PESTICIDE PROGRAMS
           WASHINGTON, D.C. 20460

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    TABLE  OF CONTENTS
                                      Page
Acknowledgments 	   1
Preface 	   1
Introduction 	   2
Forest Types 	   3
Forest Pests—Recognition and Control	   4
  Weeds	   4
  Insects  	   6
  Diseases 	   7
  Vertebrates  	   8
Pesticide Labeling	   8
Application	   8
Environmental Hazards	   9
Human Hazards	  10
                   1976
                     i

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 ACKNOWLEDGMENTS
 PREFACE
 This manual has been developed by Oregon  State
 University under  U.S.  Environmental  Protection
 Agency (EPA) contract number 68-01-2263. This
 contract was issued by the Training Branch, Opera-
 tions Division, Office of Pesticide Programs, EPA.
 The leader of this group effort was Michael New-
 ton, Oregon State University. Editors  were Mary
 Ann Wamsley,  EPA,  and Donna  M.  Vermeire,
 North  Carolina State University.

 Contributors were:
 Lawrence P. Abraham, U.S. Forest Service,
 Joseph Capizzi, Oregon State University,
 William E. Currie, U.S. Environmental Protection
  Agency,
 Charles H. Fitzgerald, University of Georgia,
 William D. Fitzwater, U.S. Environmental
  Protection Agency,
Harvey A. Holt,  Purdue University,
 Peter P. Laird, U.S. Forest Service,
 Logan  A. Norris, U.S.  Forest  Service, Corvallis,
  Oregon,
Debby J. Sundbaum, Artist, Oregon State University,
Donald P. White, Michigan State University.
 Federal regulations establish general and  specific
 standards that you must meet before you can use
 certain pesticides. Your State will provide materials
 which you may study to help you meet the  general
 standards.  This  guide contains  basic information
 to help you meet the specific standards for applica-
 tors who are engaged in forest  pest control.

Because the guide was 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:
• types of forests,
• characteristics of common forest pests,
• pest control methods,
• pesticides and  application equipment  used  in
  forestry, and
• environmental and human hazards.

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INTRODUCTION

Control  of  forest  pests  is  a  long-term  proposition.
The  goal  is to  keep pest  populations at  a  level low
             enough   to  prevent  destruction  of   forest   trees.
             Chemical pest  control must be combined with  other
             management  methods   to  minimize  recurrence  of
             pest problems.
                         FOREST   REGIONS   OF  THE  UNITED  STATES
                     WESTERN FORESTS

                     ROCKY MOUNTAIN FOREST

                      Ponderosa pine Idaho wfiiic p«*.
                      western lirch Engelmjnn spruce
                      DougJas in  lodgepole pme. tuga>
                      pme; wesle>n red cedar  western
                      hemlock, white I", and othert

                      Surplus conilers  shrubs, dwarl
                      mittletoes  and bark beetles  ire
                      important petls
                        Weslem Pine Region

                      Douglas fir western hemlock, red-
                      wood  western r«d  cedar. Silka
                      spruce  sufiar pine, lodgepole
                      p»ne.  incense  cedar, whi'c  lir.
                      Port Orford ceder  and others.
                      Hardwoods  shrubi bark beetles
                      Mna deer are important pesti

                     PACIFIC COAST  FOREST
                        Douglas Fir and
                        California Redwood Region

                     ALASKAN COAST FOREST
                      Sitka ipruce western  hemlock.
                      western red cedar Alaska cedar
                      Shrubi. browsing animals ant) de-
                      loha'or msecti are  principal pesls
ALASKAN INTERIOR FOREST
  White spruce  while birch, and
  black spruce
  Shrubs and browting animals are
  principal pests
CENTRAL  HARDWOOD
FORESTS

NORTHERN PORTION
  Oaks hickories ashes  etms  ma-
  ples, beech  black walnut, pitch.
  shortleal and Virgnia pmes.  col-
  ton wood end others
  Low-grade hardwoods,  deer  and
  gypsy molhs are principal peits
   Appalachian Hardwood Region

SOUTHERN PORTION
  Oaki. red and black gums, hick-
  ones ashes, black walnut, east-
  em red cedar, cottonwood. yellow
  poplar  beech  and others.
  Low-grade hardwoods,  deer  and
  heart'rotting  lungi are principal
  pesls.
   Southern Hardwood Region
EASTERN  FORESTS

NORTHERN  FORESTS
  Red. bitch and <*nne spruces, bat-
  sam In whttt. 'ta iack and pitch
  p«es eastern hemlock  maples
  o*k». beech, birches and aspen
  Low-grade   hardwoods,   deer
  Spruce  budworm  and  balsam
  wooty aphid  are important pests
   Northern Pint and  Hemlock and
   Northern Hardwood Rtgiont

SOUTHERN  FORESTS
  Longteal. shortleal.  loMotty  and
  tUth pinct  southern oaks  r«d
  gum: hickories southern cypress
  eastern and southern red cedars.
  •nd others
  Low-grade  hardwoods, southern
  pin* beetle. Fomut tnnotut  toot
  rot and fusiform run are pnncipal
  pests
   Southern Pme and
  Southern Hardwood Regions

TROPICAL FOREST
  Evergreen or deciduous tropical
  hardwoods
  Low-value tree
  secis are principal pesls

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Poor harvesting practices  have  left forest  prob-
lems such as weed trees, brush,  and weed-covered
lands without commercial stands. Fire control ef-
forts increase  pest-susceptible  species.  Increased
travel of man helps  introduce weeds, insects,  dis-
ease*, and animals which  may  cause  widespread
damage. Forests are attractive  to people  for  the
beauty  of the scenery, the abundance of  wildlife,
and  the quiet environment. Choose  effective pest
control  methods that are  the least  disruptive  of
these values.

Tree cover affects  all other forest resources (wa-
ter,  wildlife,  and esthetics). Methods used to  im-
prove or  protect  the  tree cover  have  a  great
influence on  the  other resources.  Pesticides  are
not generally used except to improve the  timber.
Take care to  avoid injury to the other resources.

Habitat  management will control many forest  pests.
Good vegetation control and management  will  not
only  control  pests,  but will enhance the timber
                                                  production  and may permanently solve  some forest
                                                  problems.
                                                  FOREST TYPES

                                                  The  preceding  map  shows  the principal natural
                                                  forest regions of the  United States, and  the  im-
                                                  portant  kinds of natural forest  communities  and
                                                  pests within each region.

                                                  All  regions have  second  and third  generations of
                                                  man-made  forests. These usually   are  even-aged
                                                  stands of  a single species.  They often  are  com-
                                                  posed of:

                                                  • trees not native to the area, or
                                                  • native trees which do not normally grow in single
                                                    species stands of high density. Many of the major
                                                    insect  and disease problems occur in such  man-
                                                    made forests.
I
8
                        Time to Control
                        Insects
      Time to
      Control
      Weeds
                                                                            Value of a
                                                                            Healthy Forest
                                                                                  of Forest
                                                                             it by Insects
                                                                         $ Accumulated Costs
                                                                           Value of Forest
                                                                           Held Back by Weeds
                                                                     100
                         Age of Stand (Years)

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 FOREST  PESTS-

 RECOGNITION  AND

 CONTROL

 WEEDS

 Weeds are plants that interfere with  land  man-
 agement objectives. Weeds cause more forest  losses
 than all other pests combined. Inadequate control
 of forest weeds is causing a major shortage in future
 supplies of high quality wood products. Weeds may
 be classed as:
 • weed trees,
 • brush,
 • vines, and
 • herbaceous weeds.

 Weed Trees

 Weed trees often cause significant losses  in forest
 production. They affect both young  and old  com-
 mercial trees  within the stand. Included are:
 • noncommercial hardwood  and conifer species,
 • deformed, defective,  or undersized  individuals of
   commercial  species  (such  as crooked  trees or
   those with heart rot), and
 • offsite species (commercial  species  in a location
   where they cannot develop well).
 Some weed trees may  be removed by mechanical
 methods. Some of these can be sold as pulp or fuel.
 Chemical  control methods include:
 • broadcast foliar application of herbicides,
 • directed basal-cut application of  herbicides to
   individual trees,
 • directed basal bark application of herbicides, and
 • broadcast soil application of herbicides.
 BROADCAST FOLIAR APPLICATIONS  of herbi-
 cides (usually aerial sprays) are used for:
 • Site preparation—Preparation of ground for plant-
   ing.  Treat during early or  middle part of the
   growing season. Using a controlled fire afterwards
   may be helpful.
 • Release—Removal of hardwoods  from coniferous
   stands.  Make the application during the season
   when hardwoods will be controlled with minimum
   damage  to conifers. The  label will  tell  you the
   correct season for using the herbicides  and the
   dosage at which it is selective. Season is important.
DIRECTED  BASAL-CUT  APPLICATION   OF
HERBICIDE  TO INDIVIDUAL TREES. Aerial
 sprays  are  ineffective  on some hardwood species.
 Noncommercial trees remaining after aerial applica-
 tion must be  treated individually. Otherwise, they
 may reseed  and crowd out desired species.

 Release  desirable hardwoods by  using  individual
 stem treatments on competing trees. Directed  basal-
 cut treatment usually involves applying water-soluble
 amines or various other  salts of herbicides in con-
 centrated form to cut surfaces. The cut surfaces are
 created by:
 • Girdling—removing  4-inch chips  into  the sap-
   wood to completely encircle the tree bole. Apply-
   ing herbicide spray to  the  girdle will hasten top-
   kill and retard basal sprouting.
 • Frilling—encircling the bole with a series of over-
   lapping single  line ax cuts which  penetrate the
   cambium. A herbicide must be applied  to  insure
   kill by preventing bridging. Apply  the  herbicide
   spray to the frill.
 • Felling the tree and wetting margins of cut stump
   surfaces with concentrated herbicide  spray.
 • Trunk injection—using special tools (such as the
   tree  injector  or modified hatchets)  that  inject
   herbicide concentrate.
• Putting granular herbicide (ammonium sulfamate)
   into ax-cut  cups spaced  around  the base of the
   tree near  the ground line.

DIRECTED BASAL BARK APPLICATION  to in-
dividual trees consists of  spraying a herbicide  in oil
solution on the bark of the lower one foot or bole
and exposed roots to the  point of runoff. The entire
root collar  must be  treated  without gaps.  Remove
debris first.
                 Basal Bark Treatment
BROADCAST SOIL APPLICATION OF HERBI-
CIDES  can be  used  to kill trees. They are  not
always effective.  Use them with care to avoid leav-
ing residues in soil that are harmful to  desirable

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trees. Spot treatments are more useful than broad-
cast applications.


Brush

Brush includes:
• woody shrubs, and
• noncommercial stump sprouts.
Dense  brush  keeps  light from  tree  seedlings. It
also can deprive taller commercial species of water
and nutrients. It interferes with  planting and  can
create habitat for wildlife species  that may damage
tree seedlings.

Broadcast applications of foliar herbicides are used
for general or selective control of susceptible brush
species. If the brush is  not  over  20 feet high, air
blast sprayers may  be used for ground application.
Aircraft are usually used on  taller vegetation.

Application of  chemicals  to  individual stems  can
be  expensive if large numbers of stems per acre are
treated. Basal bark applications   are effective,  but
are costly in  labor,  chemical, and  fuel oil. Systemic
brush-killing herbicides do the best job of controlling
large woody vegetation.


Vines

Greenbriar,   Japanese  honeysuckle,  wild  grapes,
kudzu, and other vines are serious pests, especially
on  better  forest soils.  They  strangle  trees,  drag
down branches  and crowns,  and  compete for light
and nutrients. Poison ivy is a human health hazard.
Vines are the most difficult weeds to control. They
have vigorous sprouting habits. Systemic  herbicides
kill  their root systems.


Herbaceous  Weeds

Herbaceous  weeds  compete with  seedlings in new
plantations.  The seedlings may develop  poorly or
die, especially  in  time  of   drought.  Herbaceous
weeds also create  favorable  cover for  tree-damag-
ing animals such as mice, gophers, and  moles. Con-
trol herbaceous  weeds  with  herbicides labeled for
this forest use. Killing all ground  cover for several
years can cause  soil damage,  especially from loss of
nutrients and from  erosion. Use banded application
in areas with summer rainfall. In dry-summer cli-
mates,  short-residual  herbicides permit  winter
ground  cover to develop.
For herbaceous  weed  control  in  new plantings,
apply herbicides in the spring before growth of tree
seedlings begins. Chemicals that injure planted trees
on contact may have to be applied before  planting
or be used as directed  spray.

Herbaceous weeds recover rapidly  after treatment
with contact herbicides. Use residual herbicides to
extend weed control through the tree seedlings' first
growing season.

Weeds of Special  Importance in
Small-acreage  Forest  Crops
Forest nurseries, seed orchards, and Christmas tree
plantings should be completely free of weed trees,
brush, and vines. Herbaceous weed control is critical
in these high-value forest crops.

Control of herbaceous weeds in forest nurseries re-
quires continuing effort  throughout the growing sea-
son. Mechanical and hand weeding  are  still  com-
mon. Preemergence herbicides are sometimes used
for selective  weed  control in conifer nurseries.

Seasonal variation in herbicidal effect on tree  seed-
lings is  critical. Use contact herbicides  when trees
are resistant and residual herbicides to carry through
sensitive period.

For control of both weeds  and diseases, fumigants
can be  used  before  seeding. Fumigants  may  injure
desirable fungi and should not be used for general
weed control.

Herbaceous weeds may  limit  seed  production in
seed orchards.  They may be controlled by  mowing
and chemical applications. Herbaceous weeds  retard
the growth  of Christmas trees and  may seriously
damage their shape.

Herbicides

You must  understand  the terms used on herbicide
labels to describe their uses in forestry. These terms
include:
•  Reforestation—the process  of establishing  tree
   seedlings.
•  Site preparation—preparing an area for reforesta-
   tion by clearing  or other vegetation control.
•  Plantation weed  contol—using herbicides for se-
   lective weed control  to insure survival and  rapid
   growth  of  planted  tree  seedlings.  This  is  one
   method of animal habitat management.

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 • Release—applying  selective herbicides to woody
   or herbaceous weeds competing with commercial
   crop species.
 • Desiccation—applying herbicides to vegetation in
   preparation for burning as part of site preparation.
 • Timber stand improvement—selective removal of
   undesirable trees to improve  growing conditions
   for desirable trees.
 • Chemical precommercial thinning—removing  all
   excess trees in a young forest by applying chemi-
   cals  to individual  trees. Herbicides labeled for
   basal spraying, cut-surface application, trunk in-
   jection, frilling, or  stump treatment may  be used
   for this purpose.
 • Preharvest drying of softwood timber—the treat-
   ment of  trees with chemicals to allow timber to
   season before cutting.  May also loosen bark and
   control insects and  diseases. Herbicides registered
   for conifer thinning may be used for this purpose.
 • Dormant  spray—applying before  buds open  in
   the spring, or after trees go  dormant in  the fall.
 • Early  foliage   spray—application  while  new
   growth is elongating rapidly, but after first leaves
   are fully expanded.
 • Summer  foliage  spray—application  to  mature
   foliage near midsummer.
 • Fall  foliage spray—application in late summer to
   early fall, generally used with  readily translocated
   herbicides.
 • Cut-surface—includes  trunk injection, bore-hole,
   frill,  frill-girdle, girdle  and stump treatment.
 • High-volume ground spray—application of herbi-
   cide  to low brush with  power sprayer delivering
   enough volume to  wet foliage to the drip point.
   Noncrop  herbicides  may  be  used  when  crop
   species are not present.
 • Low-volume spray—broadcast application by air-
   craft or ground rig, including  air  blast sprayers,
   at  the  rate of 30 gallons per  acre  or less. Does
   not soak  foliage.  Aircraft application must be
   specified  on the label.  Forestry use must appear
   on the label  if crop species are affected.

Herbicides  generally  move  very little in  forest
soils.  They are broken down in place  by micro-
organisms, sunlight,  and chemical reactions. A com-
pound that  has an effective life  of several  months
will usually move less than a foot or  two from the
site of application. Therefore, herbicides are not a
serious  threat to water supplies  or fish unless  they
are placed directly (especially by spillage) into for-
est streams or on areas which will become waterways
during storm periods.
 INSECTS
 The major groups of insects affecting forests are:
 • defoliators,
 • bark beetles,
 • suckling insects,
 • shoot borers, and
 • wood borers.

 DEFOLIATORS include:
 • forest tent caterpillar,
 • gypsy moth,
 • tussock moth,
 • spruce budworm, and
 • loopers.

 The larvae of  defoliators  feed  on  buds, flowers,
 and leaves of both hardwood and coniferous trees.
 Early spring defoliation  often keeps  the trees from
 fruiting,  reducing regeneration potential.

 Defoliation   suppresses  shoot   development  and
 growth rates. Repeated defoliation can kill the trees.
 Symptoms are the trees obviously stripped of foliage.
 One or more hatches may occur each year depend-
 ing on species and climate. The nonpersistent insec-
 ticides are most commonly  used  for  control.  Apply
 insecticides from aircraft:
 • in low volumes of oil  or water mixtures, or
 • in ultra^low  volumes of a few  ounces per acre of
   undiluted formulation concentrate.

 Timing of the application is critical to insure that:
 • the entire hatch has emerged  or will be exposed
   in later sprays, and
 • damage has  not progressed past a  harmful point.

BARK BEETLES include:
•  the southern pine beetle,
•  the western pine beetle,  and
 •  the European elm bark beetle.

Bark  beetles normally  kill some trees each year.
 In epidemic years, they  kill large numbers in some
 regions.  Their  effects  are  most  severe in unthrifty
stands and under adverse weather conditions.

Mature  insects  enter the tree and lay eggs in chan-
 nels etched between the bark and wood of conifers
 and certain hardwoods. The larvae feed on cambium
 tissue.  Their tunnels girdle  a substantial portion of
 the tree. As the tree dies,  adults emerge  and fly to
 another tree. Trees may also be  killed  by the fungi
 introduced by some beetles.

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Several hatches of bark beetle may occur each year,
depending  on species and region.  Since adults are
exposed for only  a short time, beetles  are seldom
a good target for  insecticides.

If  the pest is recognized early,  organic  arsenical
herbicides sometimes can be applied to the host tree
by  injection,  killing  the insects as  the tree dies.
Infested trees are  sometimes felled and chemically
treated. Insecticides are seldom used to control out-
breaks  except in  recreational sites, seed orchards,
Christmas tree plantations, or other high-value spe-
cial-use areas.

SUCKING INSECTS include:
• the balsam woolly aphid, and
• the beech scale.

Sucking  insects feed on  plant fluids below the sur-
faces of bark  and  leaves. Mass attacks reduce vigor
and kill shoots  and leaves.  Entire trees or stands
may be killed. Sucking insects cause scaly, mealy, or
powdery masses on trunks, twigs, and lower surfaces
of leaves.

Contact  insecticides must be used as sprays. Cov-
erage is seldom complete,  especially  for insects  on
lower leaf  surfaces. Systemic insecticides within the
tree have better control  potential.

SHOOT BORERS include both moths and weevils.
Examples are:
• the pine tip moth, and
• the white pine weevil.

Eggs are laid on  both terminal and  lateral shoots.
Developing larvae bore  down  the pith, killing the
shoot. Recognition is by dead  shoots and presence
of  larvae in central  channels.  Borers  seldom  kill
trees, but they slow tree growth and cause malformed
seedlings.

Since some  species  of  shoot borer have several
hatches each  season, use systemic insecticides.

WOOD BORERS  include:
• oak borers, and
• turpentine borers.

Wood borers  channel in the tree bole and  lower
the quality of the wood. Secondary damage is caused
by fungi that produce stains and mar the appearances
and utility of products. Borers leave holes in the
bark that frequently  exude sap. There  is no eco-
nomical control by  insecticides,  except for protec-
tion of cut timber.

Insecticides
Few insecticides  can be used for broadcast appli-
cations  in  forests.  Forest  insecticides are  used
mainly  to combat  widespread epidemics  such  as
gypsy moth and  spruce budwonn, in regional con-
trol  programs, and to  spot treat  individual plots  in
nurseries, seed orchards, and Christmas tree planta-
tions.

Like herbicides,  insecticides  are  not highly mobile
in soil. Keep insecticides away from open water by
leaving adequate  buffer strips along streams and im-
poundments when applying by air.
                               Buffer Zone between
                             /	^—(Spray and Stream
         Keep Pesticides Away
           from Open Water
DISEASES

In terms of losses  to  future forest  production,  the
rusts, root  rots, and dwarf misteltoes are the most
important diseases.

Fungicides  are not  available for use in forests. Dis-
eases cause heavy  losses in forest nurseries. Some
soil fumigants and  fungicide sprays can be used in
nurseries. Nursery  diseases  can be separated  into
these types:
•  root and soilborne  diseases, controlled by fumi-
   gation,
•  stem  and branch diseases, and foliage diseases,
   may be prevented with fungicide sprays.

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 Many  nurseries  fumigate  to  control  weeds, and
 disease control is a secondary benefit. Where  major
 disease problems  are known to  exist, fumigation can
 be used specifically for disease control. Fumigants
 are nonselective.

 VERTEBRATES
 Animals damage  trees at all stages in the develop-
 ment of the forest.
 •  Seed-eating birds and mammals can be an impor-
    tant limiting factor in natural forest regeneration.
 •  Browsing animals like deer  and rabbits  can de-
    form or kill seedlings.
 •  Mice and  mountain beaver can kill seedlings by
    completely debarking them.
 •  Birds and rodents that feed on buds can seriously
    deform trees.
 •  Pocket gophers, wild hogs, and mice can destroy
    root systems of saplings, and occasionally  larger
    trees.
 •  Bears, porcupines, mice, wood rats, and squirrels
    can kill larger  trees  by girdling.
 •  Beaver, besides felling trees, cause extensive tim-
    ber losses  from water impoundments.
L   Sharp
                   Sharp 45° Cut
                                   Top Dies

                                    Tattered Bark
                                   on Girdled Sapling
                                     from Antlers
                                       Browsed Off
                                       Stem Blunt
  Bears Strip Bark in Spring
  and Scrape Fresh Sapwood
              Dying Top
              Porcupines feed on Bark,
              Girdling, and Causing Top to Die Back
   planting stock large enough to be beyond the vul-
   nerable stage.
 • Physical control includes fencing large tracts, in-
   stalling protectors around individual trees, and
   shooting or trapping.
 • Chemical  control  includes the use of repellents
   and baits.  Many of the baits have low concentra-
   tions  of active ingredients (less than 2 percent)
   because of  their extreme  hazard to all  warm-
   blooded animals.
   Because of the reproductive potential and move-
   ments  of pest  animals, baited  areas are soon re-
   stocked with target animals, making this method
   ineffective for  long-term control.


 PESTICIDE LABELING

 Forest lands  are  considered to be cropland when  a
 stand of  commercial trees  is present.  This  means
 that "noncropland  uses" listed on a pesticide label
 may not apply to forests. Pesticides  used in forests,
 seed orchards, Christmas tree plantations, or nurser-
 ies must bear directions for use on the specific crop
 and pest  species.

Some forestry  uses are  included  on labels princi-
 pally devoted to other uses. For example, pesticides
 may be applied to Christmas trees, seed orchards, or
 nurseries  if the label  gives directions for use:
 •  on ornamentals or shade trees, including conifers,
   and
 •  for the pest you  need  to control.

Herbicides registered for  other crops, range, or
non-crop  lands may be used before crop trees are
planted.  Some  pesticides registered  for use in  for-.
estry may be tank mixed. In mixtures of two or more
products,  the rate of each  component  may  not ex-
ceed the rate prescribed on its label.  Check labels
or recognized authority for details.
                                                     APPLICATION
Control of  vertebrates  usually  is  not  feasible ex-
cept in intensively managed  forests or  in nurseries.
•  Cultural methods  include  the use of tree  species
   on which the pest will not feed, and the use of
                                      Aircraft are used  for  most forest pesticides appli-
                                      cations. Other techniques include  the use of:
                                      •  air blast  sprayers—Air blast sprayers are used
                                         most often for applying herbicides to brush under
                                         conifer  stands, or for selective  brush  control  in
                                         regenerating  stands. In these cases, the standing
                                         trees restrict air movement. This provides some
                                         drift control.

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 When using an air blast sprayer in  forests:
 Work on a calm day (less than 5 mph wind).
 Apply herbicides only in timber production areas.
 Follow local  regulations regarding distance from
 crops.
 Use operating pressure less than 20 psi.
 Use the largest practical nozzle openings.
 Do not spray under stands of sensitive desirable
 trees.
 Do not spray near recreation areas.
 tree injectors—Tree injectors are used  to control

    Injectors Apply Herbicides in Continuous
    Frills or Space Cuts at the Base of the
    Tree or at Waist Height
Basal Tree Injection
with Tree Injector
                          Spaced Cuts
Hatchet Injector
Used at Waist Level
                   Frill Cut
   woody species that have passed the "brush" stage.
   A tree injector makes a wound through tree bark
   and places herbicide in the wound. It may be a
   pipe  with a  chisel-like bit on the lower  end, or
   a  hatchet with  built-in calibrated pump. Chisel
   types are directed at the base  of the tree.  Hatchet
   types are used at any  convenient level. Injections
   are usually spaced  1 to 4 inches apart, depending
   on species and chemical.

Herbicides used in  injectors should be water-soluble
salts. They are  usually used full-strength but can be
used diluted in unmetered injectors. Esters  are less
effective.
•  directed sprayers—Some herbicides that control
   weeds can  also damage  trees.   Hand  sprayers
   equipped with shields  or with directional nozzles
   can prevent damage to seedlings. Such equipment
   also can be  mounted  on tree planting machines
   so that weeds can  be  treated  while seedlings are
   being planted if label requirements are met.
ENVIRONMENTAL
HAZARDS

The most serious adverse effects of misuse of forest
pesticides are:
•  Damage to desirable trees.
•  Injury to desirable soil organisms.
•  Elimination of desirable predator and  pollinator
   insects.
•  Unwanted changes in wildlife habitat.
•  Drift damage to adjacent crops.
•  Direct poisoning of nontarget birds and mammals.
•  Injury to fish  from application to open water.
•  Soil erosion from prolonged devegetation by re-
   peated use of residual herbicides.

Some adverse effects  are likely  even with  correct
use practices.  Pest control  decisions must  minimize
the  adverse  effects  and weigh  them  against  the
benefits.

Every  part of  a  forest changes somewhat when
another part is removed. Since pesticides act by re-
moving living  things, the entire forest responds when
a  pesticide is used.  Although the target  could be
the only organism affected  directly, other organisms
may be  affected indirectly  if they depend  on the
one(s) removed.
                                                                                           GPO 906-282

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Removing any kind of plants, for example, helps
the ones that  remain to grow better, whether they
are wanted or unwanted.

Weigh  the  environmental  consequences  of  pes-
ticide used against those of nonuse. The adverse
effects of not  using a  pesticide may last for many
decades in a forest. These effects may include:
• continuing  weed problems which  may  keep de-
  sirable trees from growing,
• insect epidemics which may totally destroy the
  forest  or  change  the species composition,
   loss of seedlings in nurseries, and
   an increase in the time needed for reforestation.
HUMAN  HAZARDS

Pesticides used  in  forests seldom come in  con-
tact with humans at exposure rates high enough to
cause injury. The risk  is greatest for applicators,
ground personnel, flagmen, or forest workers. Ob-
serve all necessary  safety precautions during and
after pesticide application.
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