630-.71Or386

;.no. 7471976

DOCUMENTCOLLECTION.

OREGGCOLLEC

Extension Bulletin 747

nsect Pests ,

OREGON STATE UNIVERSITY EXTENSION SERVICE

Cooperative Extension work in Agriculture and Home Economics, JOseph R. Cox, director. Oregon

State University and the United States Department of Agriculture, cooperating. Printed and dis-

tributed in furtherance of Acts of Congress of May 8 and June 30, 1914.

,L OREGON STATE LIBRARY

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Document Section

APR 13 1976

CORVALLIS

Revised March 1976

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T1eeta&e 94,tdeot Insect Pests

H. H. CrowellEntomologist

This bulletin has been prepared forthe home or small-acreage vegetablegrower. Commercial growers may ob-tain more appropriate information fromcounty Extension agents or from theOregon Insect Control Handbook, forsale at the OSU Book Stores, Inc.

Home gardeners can safely controlmost insect pests by the proper use ofinsecticides. There are many differentinsecticides and many ways of prepar-ing or formulating each kind. All ofthe materials recommended in this pub-lication for use in the home garden areavailable in small packages at seed orgarden-supply stores. Multipurpose in-secticides and fungicide combinationsare also available. These products willcarry the brand names of national orlocal manufacturers and the labels willlist the ingredients.

Revised by

Joseph CapizziExtension Entomology Specialist

Avoid Pesticide Residues onVegetables

Apply pesticides to plants onlyat the rates recommended.

Always wash vegetables thor-oughly in running water before using.

Strip and discard outside leavesfrom head lettuce, cabbage, and similarvegetables.

Observe the suggested time in-terval between the last application ofan insecticide and harvest. These inter-vals may vary considerably both withthe insecticide and the crops to which itis applied. The specific time intervalsbetween application and harvest arelisted on the labels. If instructions arefollowed, only insignificant amounts ofresidue will remain on the treated veg-etables.

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Do not keep pesticides in beveragebottles or other containers whichpreviously have been used for foodor drink.

When mixing and using pesti-cides, avoid getting them on theskin. Avoid spilling concentratedinsecticides on the skin. If thereis accidental contact, stop what youare doing and wash off with soapand water. Wash the hands afterspraying. It is advisable to wearrubber gloves when handling pes-ticides.

CABBAGE MAGGOTS

The "stem" or "leafy" type colecrops (cabbage, cauliflower, broccoli)do not require perfect control of theseroot maggots. Also, control is seldomneeded in the plant bed where sets fortransplanting are grown. Immediatelyafter transplanting, the sets can betreated individually as follows: dust orring the bases of the plants (i tea-spoon per plant) with chlordane ordiazinon dusts. If the maggots in yourarea are resistant to the chlordane fam-ily of insecticides, only the diazinontreatment will be effective. Liquid ap-plication of these same materials can

Dilute dust formulations are fre-quently used for home gardens becausethey are easy to handle. Some prod-ucts are sold in dual-purpose containerswhich serve as dust applicators_

Insecticides also are available asemulsifiable concentrates which form amilky emulsion when diluted withwater. These emulsions can be appliedeasily with a compressed air or trom-bone-type hand sprayer. Sprayerswhich attach to the garden hose arepreferred by some. If this type ofequipment is used, follow the manu-facturer's directions.

Wettable powder formulations re-quire constant agitation in the spraytank and cannot be applied as satis-factorily as the emulsions with the typeof equipment usually available to thehome gardener. Insecticides are some-times available in a granular form foruse as broadcast or furrow treatments.

Always read the label before usinga pesticide. Follow the manufacturer'sdirections for preparing the dilutespray. The chart on the right gives thesuggested dilution rate for the insecti-cide formulations as well as dust con-centrations usually available fromdealers.

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The pesticides suggested in this bul-letin have been selected on the basis oftheir effectiveness, availability, andsafety. These pesticides are among theless hazardous to the user, and can beused safely if precautions are observed.

Follow the manufacturer's precau-tions on the pesticide label. These arenot intended to frighten the user, butto impress upon him the need for care-ful use of pesticides.

Store pesticides in a safe place, outof reach of children.Destroy empty containers or thosewithout labels.

BaitsCarbaryl (Sevin)Chlordane*DiazinonDicofcl (Kelthane)MalathionMetaldehydeMethoxychlorRotenone

W.P. = Wettable powder.2 E.C. = Emulsifiable concentrate.

Purchase prepared2 to 4 tablespoonfuls 50% W.P.i1 to 2 tablespoonfuls 44% E.C.'2 teaspoonfuls 25% E.C.2 teaspoonfuls 18.5% E.C.2 teaspoonfuls 57% E.C.Prepared baits or 1 tablespoonful 50% W.P.1 tablespoonful 50% W.P.I to 2 teaspoonfuls E.C.

See note on page 4.

be made, if preferred, by merely spray-ing or pouring the dilute spray emul-sions at the bases of the transplants(1 cup of liquid per plant). See dilu-tion table on this page.

Protection of root crucifers is moredifficult, since one maggot can ruin theedible root. At the present time, thereis no sure way to protect turnips andrutabagas, but there are two programswhich may be suggested for home gar-deners.

The adult fly is susceptible to dustsor sprays of methoxychlor, diazinon, ormalathion and weekly applications ofone of these materials will preventmany eggs from being laid. Applica-tions should be made soon after a rainor sprinkler irrigation. Another method

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Common Insecticides and Concentrations for Small-Quantity Use

Approximate dustInsecticide Amount to mix with 1 gallon of water concentration

Ve

which has had some degree of successis the application of two or threedrenching sprays of diazinon along therows. Use one teaspoonful of liquidconcentrate in one gallon of water anduse heavily enough to wet the soilaround the roots. The first applicationshould be made when the first trueleaves are showing, the second aboutmid-season, and the last not later than10 days before maturity.

Radishes also can be protected by themethods described for turnips and ru-tabagas, but a third method may besuggested. Dilute granules or dust ofdiazinon can be sprinkled in the fur-row at the time of planting. Becausethe concentration of the granules ordusts may vary according to the manu-facturer, follow label directions for

rate of application. A small screw-capjar with holes punched in the lid canbe used to apply these dry materials.(Note: The furrow treatment methoddescribed for radishes is not recom-mended for turnips or rutabagas be-cause of injury to seedlings and lackof satisfactory maggot control on cropsthat require a longer growing period.)

ONION MAGGOTThis insect, the larva of a fly and a

"cousin" to the cabbage maggot, at-tacks only onions and a few closely re-lated plants. Early in the season, seed-lings are actually killed by the mag-gots; later on, maturing onions areruined for storage.

For effective control, sprinkle dia-zinon dust or granules into the open

Note: This bulletin is to help home gardeners controlinsects safely. If you have insect problems not coveredhere your county Extension agents can provide controlinformation. Commercial growers, pesticide applicators,and others with a professional interest in insect controlmay be interested in obtaining OSU's annually revisedInsect Control Handbook. This complete guide, and sim-ilar handbooks on Plant Disease Control and on WeedControl, are available @ $7.50 each from OSU Book-stores, P.O. Box 491, Corvallis, Oregon 97330.

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furrow at the rate of about I- table-spoonful of 4% material per 20 feet ofrow. Other concentrations of dusts orgranules can be used, but follow thedirections on the label for rate of ap-plication. A small screw-cap jar withholes punched in the lid can be usedlike a salt shaker to apply these ma-terials.

Green or bunching onions or onionsgrown for mature bulbs also may beprotected by sprays or dusts of mala-thion or diazinon. Start treating soonafter planting, before seedlings emerge.Continue dusting or spraying at 10-dayintervals until the end of June. Twoor three more treatments should bemade, but the last not closer than 10days before harvest (diazinon), or 3days of harvest (malathion).

*Many uses of chlordane were suspendedby the Environmental Protection Agency onDecember 24, 1975. However, existing stocksof chlordane may be used as labeled. Followlabel directions.

Cutworms: Several species of dingy,soil-inhabiting worms damage cropsby cutting off seedlings at the soil line,eating holes in edible roots, and feed-ing on foliage.

Grasshoppers: Well - known insectswhich may be very injurious to vege-tables and flowers in late summer.

Slugs and snails: Land molluscs com-mon to western Oregon. Very destruc-tive to seedling vegetables, flowers,and root crops, especially in rainyyears.

Earwigs: Pests of seedlings. They alsoinfest ears of corn and leafy vegeta-bles.

Symphylans(Symphylids): Small, white, centipede-like animals. They attack root sys-tems of most garden plants which theystunt or kill.

Control of Vegetable Insect Pests

--\seernak

VEGETABLES GENERALLY

Cutworm baits, available ready-mixed on the market, are effectivewhen plant growth is sparse. Baits are more effective when applied inthe evening and when the ground is wet. If worms are cutting plantsat or below the ground level, spray or dust carbaryl (Sevin) on thearea infested. When cutworms are feeding on foliage of crops suchas beets, apply carbaryl (Sevin) to the foliage.

Use sprays or dusts of malathion or carbaryl (Sevin). Attempt to keepgrasshoppers out of the garden by early application to vegetationaround outside edges.

Slug and snail baits are most effective if applied in the evening. Bait-ing in September and October after the first fall rains is particularlyeffective since this precedes the period of heaviest egg laying.

Spread earwig bait according to directions on the package. Apply inthe evening as earwigs feed at night. Malathion is also effective toa lesser degree.

No satisfactory chemical control measure is available for home gar-deners. Thorough pulverization of the soil wiih rotary tillers whenthe soil is on the dry side and easily put into good filth will scatterand destroy symphylans. This practice makes it possible to growcrops in infested soil without resorting to the use of chemicals.

Observe the suggested time interval between the last application of an insecticide and harvest.

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Insect and damage Control

Insect and damage

Wireworms: Brown, jointed larvae ofclick beetles. They kill young plants,,damage edible roots and tubers.

Spider mites: Tiny, spider-like creatureson the lower sides of leaves. Theleaves turn yellow and die.

Blister beetles: Large black or graybeetles which eat foliage of vegeta-bles and flowers.

Pillbugs, sowbugs, millipedes: Many-legged arthropods which inhabit moist,shaded areas. They may attack seed-ling plants or fruits in contact with soil.

Seed-corn maggot: White larvae of afly similar to cabbage maggot. It at-tacks most vegetables, mainly thegerminating seeds.

Asparagus beetle: Bluish-black, yellow-spotted beetle. Adults damage sproutsby feeding and egg laying. Beetlesand gray larvae defoliate ferns.

Control of Vegetable Insect PestsContinued

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Control--

To control wireworms, use a pre-planting soil treatment of diazinonor chlordane.* Apply either of the insecticides at the rate suggestedon the label and mix thoroughly with the soil to a depth of 6 to 8inches. *See note on page 4.

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Use malathion, diazinon, or dicofol (Kelthane). Direct the spray ordust to the undersides of leaves. Spider mites usually appear in lateseason. Repeated applications are often necessary for satisfactory con-trol. Do not apply diazinon or dicofol (Kelthane) to eggplant.

Use malathion, methoxychlor, or carbaryl (Sevin) sprays or dusts asneeded.

These pests prefer decaying organic matter but may be serious inwet seasons or in greenhouses. Use malathion, chlordane,* or car-baryl (Sevin). *See note on page 4.

Apply diazinon granules or wettable powder in seed furrow as sug-gested for maggots on radishes, (page 4). If damage is severe, re-plant.

ASPARAGUS

Rotenone, methoxychlor, malathion, or carbaryl (Sevin) dusts or spraysare effective on both adults and larvae. Control in late season is im-portant to reduce numbers of overwintering beetles as well as toprotect ferns.

Twelve-spotted asparagus beetle:Brick-red, black-spotted beetle. Adultsappear later in the spring and attackboth sprouts and ferns. Larvae feed onberries only.

Western spotted cucumber beetle: Yel-lowish-green, black - spotted beetlecommon to western Oregon. Adults at-tack seedlings and green pods.

Black bean aphid: Black plant lousewhich forms colonies on leaves andpods.

Nitidulid beetle: Small, black beetlesmigrate into gardens and infest blos-som of beans and cause blossom drop.A nuisance on flowers.

Western spotted cucumber beetle: Yel-lowish-green, black-spotted beetle mayattack seedlings. Feeds on foliage at allstages of plant growth.

Control measures suggested for asparagus beetle will take care ofthe 12-spotted species.

BEANS

Adults may be controlled with most insecticides recommended forhome gardens, including methoxychlor, carbaryl (Sevin), diazinon,and rotenone. Beetles frequently migrate in large numbers, so re-peated applications may be necessary.

Use malathion or diazinon as dusts or sprays when needed.

Beetles may migrate into gardens in large numbers during late Julyand early August, but they do not cause serious damage.

BEETS

Dusts or sprays of methoxychlor, diazinon, carbaryl (Sevin), or ro-tenone are effective. Apply lightly when needed.

BROCCOLI and BRUSSELS SPROUTS-See Cabbbage

Observe the suggested time interval between the last application of an insecticide and harvest.

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Aphids: Gray, mealy plant lice whichsuck sap from all cole crop plants.They form large colonies and weakenor kill the plants.

Cabbage worms: Imported or commoncabbage worm, cabbage looper, dia-mond-back moth larvae, and other cat-erpillars which feed on the foliage ofcole crops.

Root maggots: White maggots maykill or weaken plants by feeding onthe roots. The egg-laying fly is activeduring most of the season.

Cabbage flea beetle: Small, blue-black,jumping insect which eats holes inleaves of all cole crops.

Rust fly: Straw-colored maggots; ruinthe roots for eating.

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Aphids: Yellowish-gray plant lice onfoliage in certain seasons.

Control of Vegetable Insect PestsContinued

CABBAGE, CAULIFLOWER, and Other "Stem" Crucifers

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Use malathion or diazinon dusts or sprays. Start control measuresearly in the season and repeat when necessary.

Rotenone, malathion, diazinon, methoxychlor, and carbaryl (Sevin)are effective. Worms may be active during the entire growing seasonand regular applications may be necessary to protect plants.

Chlordane* or diazinon dusted or ringed (/2 teaspoonful dust perplant) around bases of plants will protect them from damage. Treat-ment should be made within 24 hours of setting plants out in thefield. See the section on cabbage maggots, pages 2 to 4. "See page 4.

Use carbaryl (Sevin), rotenone, methoxychlor, or malathion asneeded.

CARROTS

The carrot rust fly has not been a problem for several years. If itshould be causing damage, apply diazinon dust or granules in thefurrow at planting time as suggested by the manufacturer, or use di-azinon as suggested for wireworm control.

Apply diazinon or malathion sprays or dusts when needed. Aphidsare hard to see and they weaken plants if not controlled.

Insect and damage Control

Aphids: Dark-colored plant lice formlarge colonies on undersides of leavesand progressively kill foliage. They areoften attended by ants.

Squash bug: Large, dark insects appearin late spring. They suck juices fromsquash plants, kill leaves and wholevines.

Cucumber beetle: Striped beetles areserious foliage feeders in certain sea-sons. The spotted cucumber beetle isnot a serious pest of cucurbits.

Western potato flea beetle and west-ern spotted cucumber beetle: Tiny,black, jumping beetles eat holes inleaves or yellowish-green spotted bee-tles feed on young plants.

Spider mites: Tiny, spider-like crea-tures on undersides of leaves.

CUCURBITS (Squash, cucumbers, etc.)

Use diazinon or malathion sprays or dusts. Direct insecticides to theundersides of leaves, and do not apply when leaves are wet sinceplant injury may result.

Carbaryl (Sevin) directed under leaves and at the base of plants willaid in control. It is important to kill overwintered adults before theylay eggs or kill seedling plants. Hand picking is effectivebugs hideunder boards placed in fields.

Use methoxychlor, diazinon, carbaryl (Sevin), or rotenone dusts orsprays. Apply lightly. Many insecticides cause plant injury if appliedheavily and when leaves are wet.

EGGPLANT

Treat lightly with methoxychlor, malathion, or rotenone. Repeatwhen necessary.

Mites may be particularly injurious to eggplant. See "spider mites"on page 6. Do not use diazinon or dicofol (Kelthane) on eggplant.

Observe the suggested time interval between the last application of an insecticide and harvest.

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Insect and damage Control

Western spotted cucumber beetle, var-ious worms: Common black-spottedgreen beetles, alfalfa loopers, andother leaf-eating insects sometimes at-tack lettuce.

Onion maggot: White worm whichkills seedlings and ruins older onionbulbs. Parent fly lays eggs on soilaround plants.

Thrips: Tiny insects which cause foli-age to turn white or silvery and wilt.Reduces onion yields.

Pea weevil: Egg-laying weevils appearwhen first pods are setting. Grubsfeed on the inside of the green peas.

Pea aphid: Large, green plant licewhich form large colonies in the grow-ing tips of the vines.

Control of Vegetable Insect PestsContinued

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LETTUCE

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Methoxyclor, diazinon, carbaryl (Sevin), or rotenone dusts or spraysare effective. Young lettuce plants are most susceptible to attack bythese insects.

ONIONS

Use diazinon dust or granules in furrows at planting time. See thesection on onion maggots, page 4.

Use diazinon or malathion. Sprays are more effective. Thrips appearin midseason; they are not serious in western Oregon in most seasons.

PEAS

Use two or three applications of malathion, rotenone, or methox-ychlor at weekly intervals as soon as the first pods set. Early applica-tion is necessary to kill adult weevils before egg-laying starts.

Malathion or diazinon sprays or dusts are effective. Thorough appli-cation to growing tips and undersides of leaves is important.

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Western potato flea beetle: Bronze-black, jumping beetle which eats holesin the foliage.

andTuber flea beetle: Similar to westernflea beetle, but jet black. Larvae feedon and seriously damage tubers.

Colorado potato beetle: Large stripedbeetles and reddish grubs both eatfoliage and vines. They are a pest onlyin eastern Oregon.

Aphids: The same gray-colored plantlouse which infests cabbage and other"stem" crucifers (cole crops).

Cabbage flea beetle: The same blue-black jumping beetle found on othercole crops.

Diamond-back moth: Small larvae of amoth which eats holes in leaves,mostly from the undersides.

Root maggots: White maggots orworms which feed on the roots andruin them for food. The parent is a fly.

POTATOES

Apply carbaryl (Sevin) or diazinon sprays or dusts. Begin applica-tions to potato foliage when the first leaves appear. Continue ap-plications at 7- to 10-day intervals. Control is aimed at killing adultsbefore they lay eggs.

Apply carbaryl (Sevin) as necessary. The program suggested forcontrol of tuber flea beetle will control this pest. Spot treatment atintervals early in the season may save treating whole potato plant-ings later.

Use malathion or diazinon dusts or sprays. Aphids are not as impor-tant on "root" crops unless greens are to be eaten.

Apply methoxychlor, diazinon,or malathion as needed to protectthe seedings.

Use malathion, methoxychlor, diazinon, carbaryl (Sevin), or rotenonedirected to undersides of leaves.

Use the methods of control suggested in the section on cabbage mag-gots, pages 2 to 4.

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RADISHES AND OTHER ROOT CRUCIFERS

Western spotted cucumber beetle:Spotted beetles which eat holes inleaves. They may be serious on theseedling plants.

Insect and damage Control

Corn earworm: Large, green (alsobrown, black, or reddish) wormswhich get into tips of ears and feed onsilk and kernels. Serious in most areas.

Western potato and tuber flea beetles:Small, black beetles (same as onpotatoes) which attack the leaves inearly summer.

Hornworm: Very large, green wormswith diagonal stripes and a single"horn" at the back end.

Control of Vegetable Insect PestsContinued

SQUASHSee Cucurbits

SPINACH

Use methoxychlor, rotenone, diazinon, or carbaryl (Sevin) dusts orsprays.

SWEET CORN

Use carbaryl (Sevin) or malathion dust daubed onto silks of eachear with a brush. Make three to four applications at 3-day intervalsand start when silks first appear.

TOMATOES

Apply carbaryl (Sevin), diazinon, or methoxychlor lightly, as needed.Damage is most likely to occur soon after transplanting.

Hand picking of worms (or snipping with scissors) is effective insmall plantings. A pest only in eastern Oregon.

TURNIPS

See radishes

Observe the suggested time interval between the last application of an insecticide and harvest.

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