APPLY PESTICIDES CORRECTLY A GUIDE FOR COMMERCIAL APPLICATORS FOREST PEST CONTROL ..VIRONMENTAL PROTECTION AGENCY OFFICE OF PESTICIDE PROGRAMS WASHINGTON, D.C. 20460 ------- 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 ------- 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. ------- 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 ------- 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) ------- 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 ------- 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. ------- • 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. ------- 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. ------- 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. ------- 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 ------- 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. 10 ------- |