S12 General Manual: Pesticide Application Training

Pests andPest ControlClimate also affects pests indirectlyby influencing the growth and development of their hosts. The population ofplant-eating pests is related to growthof the host plants. Unusual weatherconditions can change normal patternsso that increased or decreased damageresults.Natural EnemiesBirds, reptiles, amphibians, fish,mammals, and predatory and parasitic insects feed on some pests and helpcontrol their numbers. More than halfof all insect and insect-like speciesfeed on other insects, some of whichare pests. Disease organisms oftensuppress pest populations.TopographyFeatures, such as mountains andlarge bodies of water restrict thespread of many pests. Other featuresof the landscape can have similareffects. Soil type is a prime factoraffecting wireworms, grubs, nematodes, and other soil organisms. Somepests live in heavy, poorly drainedsoil, others in light, sandy soils. Soiltype also affects the distribution ofplants (including weeds), which inturn affects the population of insectsand other plant pests.Food and Water SupplyPest populations can thrive only aslong as their food and water supplylasts. Once the food source—plant oranimal—is exhausted, the pests dieor become inactive. The life cycle ofmany pests depends on the availability of water.Agricultural ForcesUnfortunately, natural controls/forces often do not control pestsquickly enough to prevent unacceptable injury or damage—other pestcontrol methods must be initiated.Those available include: host resistance, biological control, cultural control, mechanical control, sanitation, and chemical control.6Host ResistanceSome crops, animals, and structures resist pests better than others.Some varieties of crops, wood, andanimals are immune to certain pests.Use of resistant types helps keep pestpopulations below harmful levels bymaking the environment less favorable for the pests. Host resistanceworks in two main ways: chemicals in the host preventthe pest from completing its lifecycle, the host is more vigorous ortolerant than other varieties andthus less likely to be seriouslydamaged by pest attacks.Biological ControlBiological control involves the useof naturally occurring enemies—parasites, predators, and disease agents(pathogens). It also includes methods by which the pest is biologicallyaltered, as in the production of sterilemales and the use of pheromones orjuvenile hormones. Most kinds of biological control agents occur naturally.Releasing more of a pest’s enemiesinto the target area can supplementthis natural control.Biological control is never complete. The degree of control fluctuates.There is always a time lag betweenpest population increase and the corresponding increase in natural controls. But, under proper conditions,sufficient control can be achieved toeliminate the threat to the crop oranimal to be protected. Biological control can be a low-cost control methodparticularly suited to low-value crops(pastureland, clover, and hay crops)or in areas where some injury can betolerated (golf course fairways, forestareas).Cultural ControlCultural practices are agriculturalpractices used to alter the environment, the condition of the host, orthe behavior of the pest to preventor suppress an infestation. Planting,growing, harvesting, and tillage practices sometimes can be manipulated

to reduce pest populations. Otherpractices such as crop or pasture rotation, varying the time of planting, anduse of trap crops also affect pests.Mechanical ControlDevices and machines used tocontrol pests or alter their environment are called mechanical controls.Traps, screens, barriers, radiation, andelectricity can sometimes be used toprevent the spread of pests or reducean infestation. Lights, heat, and refrigeration can alter the environmentsufficiently to suppress or eradicatesome pest populations.SanitationSanitation practices help to suppress some pests by removing sourcesof food and shelter. Other forms ofsanitation which help prevent pestspread include using pest-free seedsor plants and decontaminating equip ment, livestock, and other possiblecarriers before allowing them to entera pest-free area.Chemical ControlPesticides are chemicals used todestroy pests, control their activity, orprevent them from causing damage.Some pesticides either attract or repelpests. Chemicals which regulate plantgrowth or remove foliage may also beclassified as pesticides.Pesticides are generally the fastest way to control pests. In many instances, they are the only weaponavailable. Choosing the best chemicalfor the job is important.By selecting pesticides wisely andapplying them correctly, the responsible pesticide applicator can usethese chemicals for the benefit of theenvironment.Pest Resistance to PesticidesThe ability of pests to resist poisoning is called pesticide resistance.Consider this when planning pestcontrol programs that rely on the useof pesticides.Rarely does any pesticide kill allthe target pests. Each time a pesticideis used, it selectively kills the mostsusceptible pests. Some pests avoidthe pesticide. Others are able to with -stand its effects. Pests that are notdestroyed may pass along to theiroffspring the trait that allowed themto survive.When we use one pesticide repeatedly in the same place, against thesame pest, the surviving pest population may show greater resistance tothe pesticide than did the originalpopulation. Some pests have becomepartially immune to poisoning bycertain pesticides.Not every pesticide failure iscaused by pest resistance, however.Make sure that you have used the correct pesticide and the correct dosage,and that you have applied the pesticide correctly. Also remember, thepests that are present may be part of anew infestation that occurred after thechemical was applied.Pests andPest ControlFactors AffectingPesticide Use OutdoorsSoil Factors—Organic matter insoils may “tie up” pesticides, limitingtheir activity. Soils with high organicmatter content may need higher ratesof some pesticides for best control.Soil texture also affects the waypesticides work. Soils with fine particles (silts and clays) have the mostsurface area. They may need higherrates for total coverage. Coarser soils(sands) have less surface area. Uselower rates on them.Surface Moisture—Pesticideswork best with moderate surfacemoisture. Wetness may keep thepesticide from adequately contactingthe protected surface. Dryness mayprevent the pesticide from spreadingevenly over the surface and contacting the target pest.Rain may interfere with pest control by causing pesticides to run off orto leach down through the soil. Rainduring or soon after over-the-top orfoliar applications may wash pesticides off the plant. However, someprotectant fungicides are sometimespurposely applied just before periodsof expected high humidity and lightrain. When pre-emergence pesticidesare applied to the surface, moderaterainfall aids in carrying them down7

Pests andPest Controlthrough the soil to the pests. Rainmay also release pesticide action aftersome granular applications.Humidity and Temperature—Humidity also affects the way pesticideswork. Herbicides often work bestwhen weeds are growing fast—usually in high humidity and optimumtemperature. However, these sameconditions may make the protectedplant more susceptible to pesticideinjuries.High temperature and sunlightwill cause some pesticides to breakdown when they are left exposed ontop of the soil or on other surfaces.Low temperatures may slow down orstop the activity of some pesticides.Wind—Wind speed and directioncan greatly alter the effectiveness of apesticide application. Excessive windcan blow the pesticide off target andresult in inadequate control. Evenmoderate winds can greatly alterthe coverage of Ultra Low VolumeConcentrate Solutions (ULV) and mistblower applications. Sometimes theapplicator can compensate for minorwinds by applying the pesticidesat an angle where the winds blowthe chemical towards the area to beprotected.Principles of Pest ControlWe often talk about the “war”against insects, plant diseases, weeds,and rats. In a war between countries,would a national leader use only theArmy? Wouldn’t he/she also useother tools—Navy, Air Force, andpropaganda?Yet, in our struggle against pests,how often do we use the handiest orleast expensive pesticide? How oftendo we forget to consider other methods or combinations of methods?How often do we forget about effectson the environment? It maybe too often.The use of a combination of methods to control pests is basic to all pestcontrol. Modern pest control usesall available methods to keep pestsbelow economically harmful levels,and damages the environment as littleas possible in the process.8The challenge lies in our ability tocontrol pests so that injury caused bythem is held to a minimum, and torecognize when direct action, such asa pesticide application, is necessary.Integrated PestManagement (IPM)Integrated Pest Management (IPM)is the planned manipulation of pestpopulations in an attempt to achievea balance between costs and returns,and between farm production and theoverall environment. Integrated Pestmanagement practices include useof: cultivation, changes in croppingsequence, barriers, pest resistant ortolerant varieties, sanitation, traps,beneficial insects, timely plantingand harvesting, and judicious use ofchemical pesticides. IPM is accomplished by growers who consider allalternative pest control practices thatare available on their farms, then useone or more cost-effective pest controlpractices that are least harmful to theenvironment.Use of effective IPM practicesmust be based on current information about the pest problem, such asthe numbers and kinds of pests inthe specific crop or herd. Inadequateknowledge or improper diagnosis ofthe pest problem results in wastefuluse of time and money and disappointing control of the pest(s).Management TestsIPM must be practical and tailoredto each pest problem on your farm.Three tests of practicality are:1. Is it available (to this farm,when needed)?2. Does it fit the entire cropor herd management program(or can present management befeasibly changed to accommodatethe pest management practice(s)being considered)?3. Cost effectiveness. The “bottom line” when one’s livelihoodis involved must always be: “Willit pay?”The third factor is the basis of thetwo concepts, economic injury leveland economic threshold. Economicinjury level is the lowest number of

pests that will cause an amount ofinjury equal to the cost of appliedcontrol practices. Economic t hreshold,sometimes called the “action threshold” is the pest number or densityat which remedial control practicesshould be taken to prevent the pestsfrom exceeding the economic injurylevel. The economic threshold isnecessarily lower than the economicinjury level to allow time to applycontrol practices and to permit timefor those control practices to controlthe pests.Integrated pest managementconsists of selection of specific controlpractices which work well togetherto best solve a specific set of pestproblems under the conditions whichprevail at that time and place.InsectsThere are more kinds of insects onearth than all other living animalscombined. They are found in soil, hotsprings, water, snow, air, and insideplants and animals. They eat thechoicest foods from our table. Theycan even eat the table.The large number of insects can bedivided into three categories according to their importance to man: species of minor importance—About 99 percent of all speciesare in this category. They arefood for birds, fish, mammals,reptiles, amphibians, and otherinsects. Some have aestheticvalue. beneficial insects—In this smallbut important group are thepredators and parasites thatfeed on destructive insects,mites, and weeds. Examples areladybird beetles, some bugs,ground beetles, tachinid flies,praying mantids, many tinyparasitic wasps, and predaceousmites. Also in this category arethe pollinating insects, such asbumblebees and honeybees,some moths, butterflies, andbeetles. Without pollinators,many kinds of plants could notgrow. Honey from honeybeesis food for humans. Secretions from some insects are madeinto dyes and paints. Silk comesfrom the cocoons of silkworms.destructive insects—Althoughthis is the category which usually comes to mind when insectsare mentioned, it includes thefewest number of species. Theseare the insects that feed on,cause injury to, or transmit disease to humans, animals, plants,food, fiber, and structures. Inthis category are, for example,aphids, beetles, fleas, mosquitoes, caterpillars, and termites.Pests andPest ControlPhysical CharacteristicsAll insects in the adult stagehave two physical characteristics incommon. They have three pairs ofjointed legs, and they have three bodyregions—the head, thorax, and abdomen.HeadThe head supports antennae, eyes,and mouthparts. The antennae varyin size and shape and can be a help inidentifying some pest insects. Insectshave compound eyes, made up ofmany individual eyes. These compound eyes enable insects to discernmotion, but probably not clear images.The four general types of mouthparts are: chewing, piercing–sucking, sponging, and siphoning.Chewing mouthparts containtoothed jaws that bite and tear thefood. Cockroaches, ants, beetles,caterpillars, and grasshoppers are inthis group. Piercing–sucking mouthparts consist of a long slender tubewhich is forced into plant or animaltissue to suck out fluids or blood.Insects with these mouthparts arestable flies, sucking lice, bed bugs,mosquitoes, true bugs, and aphids.Sponging mouthparts have a tubulartongue-like structure with a spongytip to suck up liquids or soluble food.This type of mouthpart is found in theflesh flies, blow flies, and house flies.Grasshopper9

Pests andPest ControlSiphoning mouthparts are formedinto a long tube for sucking nectar.Butterflies and moths have this type.ThoraxThe thorax supports the three pairsof legs and (if present) the wings. Thevarious sizes, shapes, and textures ofwings and the pattern of the veins canbe used to identify insect species.The forewings take many forms. Inthe beetles, they are hard and shelllike; in the grasshoppers, they areleathery. The forewings of flies aremembranous; those of true bugs arepart membranous and part hardened. Most insects have membranoushindwings. The wings of moths andbutterflies are membranous but arecovered with scales.Insect eggsAbdomenThe abdomen is usually composedof 11 segments. Along each side ofmost of the segments are openings(called spiracles) through which theinsect breathes. In some insects, thetip end of the abdomen carries taillike appendages.Insect DevelopmentGradual MetamorphosisComplete Metamorphosis10Most insect reproduction resultsfrom the males fertilizing the females.The females of some aphids andparasitic wasps produce eggs without mating. In some of these insectspecies, males are unknown. A few insects give birth to living young; however, life for most insects begins as anegg. Temperature, humidity, and lightare some of the major factors influencing the time of hatching. Eggs come invarious sizes and shapes—elongate,round, oval, and flat. Eggs of cockroaches, grasshoppers, and prayingmantids are laid in capsules. Eggsmay be deposited singly or in masseson or near the host—in soil or onplants, animals, or structures.MetamorphosisThe series of changes throughwhich an insect passes in itsgrowth from egg to adult is called metamorphosis.When the young first hatches froman egg, it is either a larva, nymph, ornaiad. After feeding for a time, theyoung grows to a point where theskin cannot stretch further; the youngmolts and new skin is formed. Thenumber of these stages (called instars)varies with different insect speciesand, in some cases, may vary with thetemperature, humidity, and availability and kinds of food. The heaviestfeeding generally occurs during thefinal two instars.No MetamorphosisSome insects do not change exceptin size between hatching and reaching the adult stage. The insect growslarger with each successive instar until it reaches maturity. Examples aresilverfish, firebrats, and springtails.The food and habitats of the young(called nymphs) are similar to thoseof the adult.Gradual MetamorphosisInsects in this group pass throughthree quite different stages of development before reaching maturity:egg, nymph, and adult. The nymphsresemble the adult in form, eat thesame food, and live in the same environment. The change of the body isgradual, and the wings (when present) become fully developed only inthe adult stage. Examples are cockroaches, lice, termites, aphids, andscales.Incomplete MetamorphosisThe insects with incomplete metamorphosis also pass through threestages of development: egg, naiad,and adult. The adult is similar to theyoung, but the naiads are aquatic.Examples: dragonflies, mayflies, andstoneflies.Complete MetamorphosisThe insects with complete metamorphosis pass through four stagesof development: egg, larva, pupa,and adult. The young, which may becalled larvae, caterpillars, maggots, orgrubs, are entirely different from theadults. They usually live in differentsituations and in many cases feed ondifferent foods than adults. Examplesare beetles, butterflies, flies, mosquitoes, fleas, bees, and ants.Larvae hatch from the egg. Theygrow larger by molting and passing

through one to several instars. Mothand butterfly larvae are called caterpillars; some beetle larvae are calledgrubs; most fly larvae are calledmaggots. Caterpillars often have legs;maggots are legless. Weevil grubs arelegless; other kinds of beetle larvaeusually have three pairs of legs.The pupa is a resting stage duringwhich the larva changes into an adultwith legs, wings, antennae, and functional reproductive organs.Insect-Like PestsMites, ticks, spiders, sowbugs,pillbugs, centipedes, and millipedesresemble insects in size, shape, lifecycle, and habits. Pest species usuallycan be controlled with the same techniques and materials used to controlinsects.ArachnidsTicks, scorpions, spiders, andmites have eight legs and only twobody regions. They are wingless andlack antennae. The metamorphosisis gradual and includes both larvalnymphal stages. Eggs hatch intolarvae (six legs) which become nymphs(eight legs) and then adults. Ticks andmites have modified piercing–suckingmouthparts: spiders and scorpionshave chewing mouthparts.CrustaceansSowbugs and pillbugs, water fleas,and wood lice have 14 legs. Theyare wingless and contain only onesegmented body region. They havetwo pairs of antennae and chewingmouthparts. Sowbugs and pillbugshave a hard, protective shell-likecovering and are related to the aquaticlobsters, crabs, and crayfish. Themetamorphosis is gradual, and theremay be up to 20 instars before adulthood is reached.Centipedes and MillipedesCentipedes are made up of30 seg ments, each containing one pairof legs. They have chewing mouthparts. Some species can inflict painfulbites on humans.Millipedes contain 30 segmentsand are cylindrical like an earthworm.The body is wingless and each seg-ment bears two pairs of legs. Theantennae are short and mouthpartsare comblike. Millipedes feed ondecaying organic matter, seeds, bulbs,and roots.There is no metamorphosis; centipedes and millipedes do not changeexcept in size between hatching andreaching the adult stage.Pests andPest ControlControlling InsectsControl of insects and their relatives may involve any of the threebasic pest control objectives. Controlis usually aimed at suppression ofpests to a point where the presence ordamage level is acceptable. Prevention and eradication are useful only inrelatively small, confined areas suchas indoors or in programs designed tokeep foreign pests out of a new area.The key to successful control ofinsect and insect-like pests is knowledge of the stage(s) of their life cyclein which they are most vulnerable. Itis generally difficult to control insectsin either the egg or pupal stage,because these stages are inactive: notfeeding, immobile, and often in inaccessible areas such as underground,in cocoons or cases, and in cracks orcrevices.Controlling insects in the lateinstar and adult stages is moderatelysuccessful. The ins

pest from causing more damage than is reasonable to accept. Even though a pest is present, it may not do very much harm. It could cost more to control the pest than would be lost because of the pest's damage. The three main objectives of pest control are: prevention—keeping a pest from becoming a problem, suppression—reducing pest