gumeInsects of Oregon

Federal Cooperative Extension Service Oregon State College, Corvallis

Extension Bulletin 749 August 1955 Legume of Oregon

Page How to Mix and Apply Insecticides Insecticide Formulations 4 Equipment and Application 6 Residue on Forage 6 Precautions in the Use of Insecticides 6

Chart of Insects Attacking Legumes 7

How to Identify and Control Injurious Insects caterpillar 8 Ladino clover seed midge 21 Alfalfa looper 8 Leafhoppers 21 Al f alf a 8 Lesser clover leaf weevil 21 Blister 10 Lygus bugs 22 Clover aphid 10 Meadow spittlebug 24 Clover case bearer 10 Nitidulid 24 Clover flower midge 11 Omnivorous leaf tier 25 Clover leaf weevil 12 aphid 26 Clover root borer 13 Pea leaf weevil 27 Clover root curculio 14 Pea weevil 27 Clover seed chalcid 15 Slugs 28 Clover seed weevil 16 Spider mites 30 Cutworms 18 Sweetclover weevil 31 Field crickets 19 Thrips 32 Grasshoppers 19 Vetch weevil 32 Western spotted cucumber beetle 33

How to Identify and Protect Beneficial Insects Damsel bugs 35 Minute pirate bug 37 Geocorus bugs 35 Parasitic insects 37 Lacewings 36 Syrphid flies 38 Ladybird beetles 36

Protect Bees 39

2 . E. A. DICKASON, Assistant Entomologist, and R. W. EVERY, Extension Entomology Specialist Oregon State College

T F YOU are raising legumes for hay or seed, it is very likely you will have trouble with insects. Some insects attack foliage, others the blossoms or seeds. Still others damage roots or injure plants in the seedling stage. Informa- tion in this bulletin is the result of experimental work done at Oregon State College, other state college experiment stations, and by the U. S. Department of Agriculture. In the illustrations, actual size of the is shown as well as an enlarged drawing to aid in identification. Host plants and distribution of insects in the state, while not complete in all cases, help in recognizing insect pests. As a further aid in identifying injurious insects, the diagram on page 7 shows the point of attack of the most common pests.

Mrs. Patricia R. Hansen, Corvallis, made the insect drawings in this bulletin.

3 Insecticide Formulations Pure insecticides are usually coarsein water, not dissolved. For this reason, or sticky solids or syrupy liquids thatsuspensions require constant mechani- cannot be sprayed or dusted. The in-cal agitation to prevent solid particles secticide is usually diluted with a neu-from settlingto the bottom of the tral carrier which may be an inert dustspraytank.Suspensionspraysare or a liquid. Water will not dissolveabrasive and cause rapid wear in gear- most insecticides. They may be sus-type pumps. pended, however, as fine particles in Suspension sprays are less hazardous water, or may be dissolved in a solventto the operator than solutions or emul- later emulsified in water. Some insecti-sions as most suspensions are not read- cides may be dissolved in kerosene orily absorbed through the skin. In han- other organic solvents to produce adling highly toxic insecticides, such as true solution. parathion, extreme caution should be observed not to inhale insecticides when Dusts concentrated wettable powder is emp- Most insecticidal dusts contain antied into the spray tank because the inert carrier such as talc, clay, or dia-powder has a tendency to billow up tomaceous earth. Others, such as sulfurfrom the tank opening. Suspension dusts, are merely finely ground insecti-sprays are also lesslikely to cause cides. Dusts are not as readily absorbedfoliage burning than the solution or through the skin as sprays, but mayemulsionsprays.Wettable powders be dangerous if inhaled. usually contain from 15 to 75 per cent Dusts usually contain from 1 to 10active ingredients. The amount of wet- per cent active ingredients. The per-table powder to be used per acre can be centage of actual insecticide in the dustdetermined from Table 1 on page 5. mixture is stated on the label. ThisFor example, 1 pound of actual DDT must be taken into consideration inper acre is suggested for vetch weevil computing the amount of mixed dustcontrol. If a 50 per cent wettable pow- to apply per acre. For example, 2der is used, it would require 2 pounds pounds of actual toxaphene per acre isof wettable powder, diluted with water, one of the suggested insecticides forfor each acre treated. control of lygus bugs on alfalfa or Ladino clover. If a 10 per cent dust isEmulsifiable concentrates applied, it would require 20 pounds of Emulsifiableoremulsion concen- the dust per acre. The amount of dusttrates are made by dissolving the tech- needed for any control is easily deter-nical grade insecticide in an organic mined from Table 1 on page 5. solventand adding an emulsifying agent. The concentrated material is di- Wettable powders luted with water to form an emulsion. The wettable powders, used to pre-Emulsion sprays are not abrasive and pare suspension sprays, contain an in-can be used in all types of sprayers. secticide blended with an inert dust. A Emulsion concentrates usually con- wetting agentisadded tofacilitatetain from 11 to 8 pounds of active mixing the powder with water. Thisingredientoractualinsecticide per forms a suspension rather than a solu-gallon. The amount is stated on the tion, as the fine particles are suspendedlabel. This is helpful in determining

4 the dosage to use in insect control. ForOil solutions example, in the early season control of Many insecticides are soluble in ker- alfalfa weevil, heptachlor at the rateosene, fuel oil, or other organic sol- of 4 ounces of actual material per acrevents. When applied as sprays, the is one of the suggested materials. Thesolvent evaporates from treated sur- 25 per cent emulsion concentrate con-faces leaving a deposit of insecticide. tains 2 pounds of heptachlor per gal-Oil solutions are widely used on spe- lon. When diluted with sufficient water,cialized insect control projects, such as 1 gallon, therefore, would treat 8 acres.forest insect pest control or grasshop- The amount of concentrate neededper control on rangeland. Oil solutions per acre can be determined from Tablelend themselves to low gallonage per 1 below. acre airplane application. For exam- Extreme caution should be used inple, to control grasshoppers on range- handling emulsion concentrates of pa-land, only 2 to 3 ounces of aldrin in rathion, TEPP, metacide, and demeton1 gallon of fuel oil per acre is required. (Systox). These are very toxic mate-Oil solutions are not recommended for rialsand can bereadilyabsorbeduse on legume crops because of the through the skin. Be sure to followdanger of burning foliage and blossoms precautions on the label. with the solvent.

TABLE 1. INSECTICIDE APPLICATION. APPROXIMATE AMOUNTS OF FORMULATION NEEDED PER ACRE TO OBTAIN SPECIFIED AMOUNTS OF ACTUAL INSECTICIDE PER ACRE Desired insecticide per acre Formulation 2 ounces 4 ounces 8 ounces 1 pound 2 pounds Emulsionconcentratecontain- ing 11 lbs. actual insecticide per gallon. A qt. 5 qt. 11 qts. 25 qts. 11 gals. Emulsionconcentratecontain- ing 2 lbs. actual insecticide per gallon. 1 pt. 1 pt. 1qt. 2 qts. 1 gal. Emulsion concentratecontain- ing 4 lbs. actual insecticide per gallon. 4 pt. 5 pt. 1pt. 1 qt. 2 qts. Emulsionconcentratecontain- ing 8 lbs. actual insecticide per gallon. i pt. 4 pt. 1 pt. 1 pt. 1 qt. 25% wettable powder 8 ozs. 1 lb. 2 lbs. 4 lbs. 8 lbs. 40% wettable powder 5 ozs. 10 ozs. 14 lbs. 25 lbs. 5 lbs. 50% wettable powder 4 ozs. 8 ozs. 1 lb. 2 lbs. 4 lbs. 75% wettable powder 3 ozs. 6 ozs. 9 ozs. 11 lbs. 25 lbs. 1% dust 121 lbs. 25 lbs. 50 lbs. 100 lbs. 200 lbs. 21% dust 10 lbs. 20 lbs. 40 lbs. 80 lbs. 5% dust 10 lbs. 20 lbs. 40 lbs. 10% dust 10 lbs. 20 lbs.

5 Equipment and Application Most of the legume insects can bethan wettable powders should be used controlled with either aerial or groundin most types of low volume sprayers. application of dusts or sprays. Wettable powders require constant me- Dusts may be applied by airplane orchanicalagitationto keep them in ground duster. If a ground duster issuspension, cause excessive wear to used, a canvas drag behind the dustersome pumps, and frequently clog noz- will insure better coverage and improvezles. When using low volume sprayers, the control. With aircraft, the effectivethe best coverage is obtained when at swath width and the evenness of distri-least 15 to 20 gallons of spray per acre bution is less with dusts than it is withis applied. Nozzles that deliver a flat, sprays. To avoid drift, the dust shouldfan-shaped spray pattern are commonly be applied when there is no wind. used with low pressure, low volume In recent years, sprays have beensprayers. If the sprayer has been previ- used more than dusts for insect controlously usedtoapply hormone-type on legume seed crops. Aerial sprayherbicides such as 2,4-D, 2,4,5-T,it planes are usually equipped to applyshouldbethoroughlycleanedand either wettable powders or emulsionrinsed with sal soda, lye, or other neu- concentrates. Airplane sprays are usu-tralizing agents before being used to ally applied in 4-6 gallons of water perapply insecticides. acre. The airplane pilot frequently re- Orchard-type hydraulic sprayers hav- quests the grower to furnish flagmen,ing plunger or piston type pumps can or mark the effective swath width ofbe used for the control of legume in- each flight run along the edge of thesect pests. Wettable powders as well as field. emulsion concentrates can be used sat- Weed sprayers designed to apply lowisfactorily in these pumps. Nozzles volumes of spray at low pressures arethat deliver a cone-shaped spray pat- often used to apply insecticides. Emul-tern are frequently used with these sion concentrates of insecticides, rathersprayers.

Residue on Forage Do notfeed orpastureforageplication and feeding or pasturing of treated with insecticides to dairy cattlethe forage. For example, if aldrin is or being finished for slaughter.used for alfalfa weevil larvae control, The length of time a chemical residuethe label will probably state that the remains on the crop varies with theinsecticide should not be applied within insecticide used and the amount ap-15 days of cutting for forage or pas- plied per acre. Check the label for theturing. recommended time interval between ap-

Precautions in the Use of Insecticides Chemicals which willkillinsectschlor is relatively safe, malathion some- should be regarded as dangerous towhat less. DDT and chlordane are safe man and other animals. Insecticidesif used with reasonable precautions. vary widely in their toxicity. Methoxy-More care is required in the use of

6 heptachlor, aldrin, and dieldrin. The Read the label carefully. organic phosphorus insecticides such as Follow instructions on the label. parathion, TEPP, and demeton (Sys- Store out of reach of children. tox) are highly toxic and must be Dispose of empty containers. handled with extreme caution. If you plan to use one of the dan- To be safe and to keep your chil- gerous organic phosphorus com- dren safe, observe all the following pounds follow directions for their precautions regarding all pesticides. use on the label.

Insects Attacking Legumes

and Stems Alfalfa weevil Aphids Clover leaf weevil Clover root curculio 0Leaves

Cutworms Grasshoppers Lesser clover leaf weevil Slugs Spider mites

Flowers Seeds Aphids Clover seed chalcid Flower (or seed) midge Clover seed weevil Grasshoppers Pea weevil Lesser clover leaf weevil Vetch weevil Lygus Nitidulid beetles Spider mites Thrips

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; Roots Clover root borer Clover root curculio

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Alfalfa Caterpillar Colias philodice eurytheme Bdvl. The alfalfacaterpillarissmooth-wings. It is commonly found in Oregon bodied and green. It feeds on the foli-but rarely causes damage. Methoxy- age of alfalfa. The adult is a small yel-chlor is suggested for the control of low butterfly with a black border on itslarvae on alfalfa grown for hay.

Alfalfa Looper Autographa californica (Speyer) This insect belongs to the cutwormcrops, flowers, and weeds. DDT as family. Adult moths are dull gray orsuggested for lygus bug control is ef- brown. Mature larvae are slightly overfective in controlling them. Autogra- an inch long, dark olive green in colorpha falcif era (Kirby) is a closely re- with darker stripes down the back.lated species for which there is no They move in a looping fashion fromcommon name. They occur at higher which habit they derive their name.elevations in eastern Oregon. Larvae They are found in most parts of Ore-of this species are brown instead of gon and feed on alfalfa, , andgreen. other legumes as well as many garden

Alfalfa Weevil postica (Gyn.)

Description Adults are about 3/16 inch long with a medium-sized beak. Newly emerged adults are grayish in color with a broad brownish stripe down the back. As the fine scales covering the body are rubbed off, the beetles become darker. Over- wintering beetles are almost black. The is green with a white stripe along the middle of the back. When full grown, larvae are about inch long. Host plants Damage caused by the alfalfa weevil is confined to alfalfa. It is found in ALFALFA WEEVIL. Adult actual size and enlarged. Baker, Malheur, Union, Harney, Jack- Note stripe down back of larva. son, Lake, and Klamath Counties.

8 Life history gives the leaves a ragged or lace-like Adults overwinter in alfalfa stubble,appearance. This reduces the yield and along ditch banks, and field borders. Aquality of hay. Continued feeding of few occasionally overwinter inthe larvae on stubble after the first the egg stage. Weevils resume activitycutting is removed delays the second with the first warm weather in thecrop. This delay is most serious if the spring. The first eggs are laid in deadwater supply is short or the second alfalfa stems on the ground. Later,crop is grown for seed. eggs are laid in the stems of the grow-Control ing plant. Each female is capable of The alfalfa weevil can be controlled layingseveral hundredeggs.Eggs hatch during May and early June.by application of insecticides in the early spring.Insecticides applied as Larvae may be found feeding on thesprays or dusts in the spring before the plantsuntilearlyJuly. Each larva feeds for approximately 3 weeks be-alfalfa is 2 inches high will kill the fore it drops to the ground to pupate inadult weevils before they have had an opportunity to lay many eggs. Apply an oval net-like cocoon. In about 10 to 12 days the weevil emerges from thethe insecticides on a sunny day when beetles are active. cocoon. These adults are active in the If you are unable to treat the field field until cold weather approaches. before plants are 2 inches high, you can control the larvae later in the sea- Damage son. Make this application when you Adults feed on the alfalfa plant, butnotice the larvae damaging the plants. do not cause serious injury. It is the You can destroy many of the larvae feeding of larvae that must be pre-by cutting the hay crop in the bud vented. The most serious damage is tostage. In some seasons this is all the the first hay crop. Feeding of larvaecontrol needed.

TABLE2.SUGGESTED RATES OF INSECTICIDE APPLICATION FOR ALFALFA WEEVIL

Amount per acre Time and control Spray Dust Adult controlEarly spring application Heptachlor 4 ozs. (actual) 12 lbs. 21% Dieldrin 4 ozs. (actual) 20 lbs. 11% Chlordane 11-2 lbs.(actual) 30-40 lbs. 5% Larval controlEarly summer application Heptachlor 1 oz.(actual) 5 lbs. 11% Aldrin 2 ozs. (actual) 15 lbs. 1% Lindane 2 ozs. (actual) 15 lbs. 1% Parathion 4 ozs. (actual) 25 lbs. 1% Methoxychlor 1-2 lbs. (actual) 30-40 lbs. 5% Blister Beetles Epicauta spp. Blister beetles occasionally cause lo-feed on foliage ; immature forms are calized damage to alfalfa and clover.often beneficialsince they feed on The species most likely to be encoun-grasshopper eggs. Control of the adults tered are slender, soft-bodied, black oris seldom necessary ;but, if needed, gray beetles aboutinch long. AdultsDDT or malathion is effective.

Clover Aphid Anuraphis bakeri (Cowen) Description summer depending on weather favor- Clover aphids are small and lightable to their development. green or pinkish-green in color. TheyDamage hide in protected places on the plant Feeding of aphids on plant juices and may be found in great numbers indevitalizes the plant and probably re- the blossoms and beneath the leaf stip-duces seed yield. The most noticeable ules. Probably you will first notice thedamage is caused by the honeydew aphids because heads have becomewhich makes harvesting difficult. Seed sticky with honeydew. caked with honeydew isdifficult to clean without special treatment. Honey- Host plants dew is soluble in water. Late season Clover aphids prefer red and alsikerains or overhead irrigation frequently clover, but may attack white or Ladinoclean the heads of honeydew and sim- clover. The insect is present in all seedplify harvest. producing areas. Control Natural parasites and predators, un- Life history derfavorableconditions,arevery Sometimes aphids remain in cloverhelpful in reducing damage by clover fields all winter. In the fall, they mayaphids. There is no satisfactory chemi- migrate to fruit trees which serve as ancal control. Since aphids are in pro- alternate host. Aphids resume activitytected portions of the plant, it has been in legume fields in early spring. Con-difficult to reach them with an insec- tinuous generations are produced allticide.

Clover Case Bearer Coleophora spissicornis Haw. This insect attacks Ladino clover inand reduce seed yields. Adults are California and has been collected inshiny, black moths about inch long. southern and central Oregon. LarvaeThe base of the antenna is fuzzy and make a case from flower parts (florets)has a ringed appearance at the tip. which serves as a protective covering.There is no suggested control program. They feed upon the florets and seeds

10 Clover Flower Midge Dasyneura leguminicola (Lint.)

Description coon in early spring. Adults emerge in This insect is also called the cloverlate April and May and lay eggs in the seed midge. It attacks red clover andimmature red clover flowers. Larvae should not be confused with the Ladinofeed on the flower parts which would clover seed midge, Dasyneura gentneri,normally develop into seed. They later which attacks Ladino and alsike clover.drop to the soil, pupate in a cocoon, The adult is a small, mosquito-like fly.and by mid-July the new generation of The tiny larva, found in the seed pod,adults emerge. There are one or two is creamy white when small, graduallycomplete generations produced each changing to salmon-pink as it matures.season. Maggots of the last generation do not pupate, but remain in their Host plants cocoon for hibernation. Red clover is the principal host plant of the clover flower midge. It is a pest Damage in the Willamette Valley. Larvae, sucking juices from the de- veloping seed ovaries, prevent the for- Life history mation of seed. Damaged clover heads Clover flower midges overwinter inhave an irregular or lopsided appear- the larval stage. They hibernate in tinyance. Petals of infested florets fail to paper-like cocoons which are on oropen and contrast sharply to the nor- slightlybelowthesurfaceofthemal open florets of the uninfested blos- ground. They pupate within this co- soms.

Control You do not need to use chemicals to control the clover flower midge. The insect can be controlled by cutting the hay crop before, or during, the first week in June. This will destroy the maggot beforeitcan completeits development. It is important to remove the hay from the field as soon as possible after cutting. If rain falls on the hay after it has been cut, larvae are able to con- tinue their development. If the first CLOVER FLOWER MIDGE. Adult actual size and cutting is for silage, make it after May enlarged. Larva or maggot of midge. 15.

11 Clover Leaf Weevil Hypera punctata (Fabr.) Description late fall do not hatch until the follow- This is one of the largest weevilsing spring. Larvae may feed during you will findin clover and alfalfaperiods of mild weather in the fall, or fields. The adult is about i inch longwinter, but most of the damage is in with a short, but distinct, snout. It hasthe spring. In late spring, they spin a a mottled, grayish-brown appearancenet-like cocoon and pupate in the soil or and indistinct stripes along the back.among surface debris. Adults emerge The sides and underside of this beetlein June and July and are active until are yellowish-brown. The full grownearly fall when they lay eggs on or larva is aboutinch long, green to yel-near plants. There is one generation a lowish-green in color, and has a paleyear, white line down the center of the back. Damage Host plants In some seasons, serious damage is The clover leaf weevil is reported tocaused by larvaefeedinginearly attack many plants, but in Oregon it isspring just as plant growth begins. most common on alfalfa, alsike andThey are active in late afternoon and Ladinoclover.Theinsectoccursevening. During the day they are con- throughout the state, but usually incealed around the base of plants. Lar- damaging numbers onlyincentralvae eat small holes in the leaves and Oregon. irregular patches from the leaf margin. When infestation is severe, damaged Life history plants may be killed or retarded in The winter is most commonly passedgrowth. Adults feeding on plants in the in the larval stage. Some eggs laid insummer do not do much damage. Control A fungus disease usually attacks the larvae during cool, moist springs. This results in a natural control of the in- sect. Growers often notice these black and shriveled larvae curled around the stems of the plant. Some years chemical control may be necessary. Insecticides should be ap- plied when damage is noted and larvae are actively feeding on the plants. If a field is "trashy" from the previous sea- son's harvest debris, it is advisable to rake the field before application and expose the plants to insecticides. For early spring larval control, apply 30 to 40 pounds of 40% calcium ar- senate dust per acre ;or apply toxa- CLOVER LEAF WEEVIL. Adult actual size and phene-20 pounds of 10% dust, or 2 enlarged. Larva in typical curved position. pounds (actual) per acre as a spray.

12 Clover Root Borer Hylastinus obscurus (Marsh.) Description the larval stage. In April and May, Adults are about 1/10 inch long, dullbeetles leave the roots and fly to unin- black or dark brown in color. They willf ested plants within the field or to new be found in burrows within the cloverfields. If the spring is wet and cool, the roots except during a short flight pe-flight may continue into June. Eggs are riod in spring. Larvae are also foundlaid in the crown of the plant. The in burrows in the roots. They are aboutlarvae burrow in the roots and feed 1/10 inch long, creamy white, withabout 2 months before pupating in brown heads. their tunnels. New adults feed within the roots until cool weather in the fall. Host plants There is one generation a year. It is a serious pest of red clover in western Oregon and Malheur County. It has not been found in central Ore- gon, but may occur in other parts of the state. In the Willamette Valley it attacks peas and vetch, but has not been a serious pest on these crops. Life history The insect spends the winter pro- tected in clover roots. Most of them overwinter in the adult stage, a few in

Tunnels in root formed by the clover root borer.

Damage Injury occurs the spring following seeding. The first cutting, taken for hay or silage, is usually not affected. During the summer there is a conspic- uous decline in the plants from which you will get your seed crop. Severity of this damage will vary with the in- festation and moisture and weather conditions existing during the sum- mer. Injured plants can produce a seed crop if they are not killed early in the season. CLOVER ROOT BORER. Adult actual size Second-year fields often look good and enlarged. in the early spring, only to succumb

13 after the growing season starts. Exam-tack when the female beetles attempt ination of roots will enable a growerto deposit their eggs. to determine whether the field should Fields are treated the spring follow- be kept or plowed. ing seeding. That is, the first seed crop Control year. Fields seeded in Februarywith- It is possible to control the cloverout a companion crop may be attacked root borer and prolong the life of theif the clover roots reach g inch in stand. Aldrin or heptachlor dusts ap-diameter before the spring flight of plied at the rate of 2 pounds of actualbeetles is completed. Under good grow- insecticide per acre are effective. Applying conditions clover may attain this 40 pounds of 5 per cent, or 80 poundssize by June, in which case an insecti- of 2i per cent heptachlor or aldrin dustcide application in April is justified. in mid-April before the clover rootThere is no benefit in treating old red borers begin their spring flight. Thisclover stands. Plants infested from the application will protect plants from at-previous season cannot be saved.

Clover Root Curculio Sitona hispidula (Fabr.) Description covered with small curved hairs. The General color of the weevil is graybeak is short and blunt in contrast to or brown. It is about 1/6 inch long andother weevils. Sometimes this insect is called the clover root weevil. Larvae are about the same length asthe adult, legless,grayish-white with a brown head.

Host plants The cloverrootcurculioattacks practicallyall legume plants and is present in all seed-producing areas.

Life history Winter is spent in both the adult and egg stages. Some eggs are laidin the fall and winter during periods of mild weather. Eggs are laid in debris and on the soil surface. Most eggs arelaid in the spring. Larvae feed on the roots about 3 weeks before pupating in small, earthen cells. Adults emerge during the summer. There is one generation a year.

Damage

CLOVER ROOT CURCULIO. Adult actual size and Injury caused by adults feeding on enlarged. Larva greatly enlarged. the foliage is not important. Leaves

14 Control A control program is suggested for alsike clover even though it has been difficult to evaluate the benefit to seed production. A surface application of DDT to kill adults before they lay many eggs has been effective in Klam- ath County. Dusting with 20 pounds of 5 per cent DDT per acre, or an application of spray at the rate of 1 pound of actual DDT per acre is suggested. In those years when it is cold during Root injured by the larvae of the the fall and winter months, very few Clover Root Curculio. eggs are likely to be laid until spring. Application ofinsecticidesinearly havesmallcrescent-shapedpatchesspring on warm sunny days will con- eaten from the margins which will helptrol the adults before they lay many you recognize the presence of beetles eggs. in the field. Most of the damage is caused by If the fall is warm and sunny, beetles larvae feeding on the small fibrousare likely to lay a considerable number roots, gnawing cavities and groovesof eggs. Under these circumstances fall on the main root. This damage is asso-application of insecticides is preferable. ciated with declining crop stands, butIn some fields there may be a migra- it has not been possible to prove thattion of beetles which will necessitate a this decline is entirely due to the insect.second treatment in the spring.

Clover Seed Chalcid Bruchophagus gibbus Boh. Description foot trefoil (lotus), sub clover, and bur This insect is known both as theclover. It occurs in all seed-producing clover seed chalcid and alfalfa seedareas of Oregon. chalcid. Adults are black, wasp-like, and about 1/12 inch long. The shiny, me- tallic appearance of the body and al- most complete absence of wing veins arehelpfulindistinguishing them from other small wasps in the field. Small, white, plump larvae are found within the infested seeds. Host plants

The clover seed chalcid attacks al- CLOVER SEED CHALCID. Adult actual size falfa, red clover, crimson clover, birds- and enlarged.

15 Life history on the seed contents. There are at least Larvaeoverwinterwithinseeds.two or three generations each year. These seeds may be on the surface ofDamage thefield,inunharvestedfields,or screenings and straw stacks. In the Oregon seed growers lose heavily spring, larvae pupate within the seeds.from this insect some seasons. Much Adults chew a small hole in the seedof this loss is unnoticed because seeds through which they emerge to attackfrom which adults have emerged, and blossoms of the first seed crop. Eggsmany of the infested seeds, are blown are deposited within the developingout at harvest. seeds. Larvae feed for about 2 weeks Control There is no chemical control for the clover seed chalcid. It is generally be- lieved that insecticides applied to con- trol other pests are helpful in reducing chalcid infestation. Growers who plant clean seed and controlvolunteerhostplantswith herbicides along ditch banks and along field borders do much to reduce chalcid numbers. In addition to these practices, it would be helpful if they could feed or destroy screenings and chaff stacks Seed damaged by the Clover Seed Chalcid. before chalcids emerge in the spring.

Clover Seed Weevil Miccotrogus picirostris (Fab.)

Description Life history The clover seed weevil is a small Adult clover seed weevils overwinter gray insect about 1/10 inch long. Itsin fence rows and field trash. They be- small size and long beak easily separatecome active in the spring and lay eggs it from the other weevils commonlyon the florets. Eggs are deposited at found in clover. A full-grown larva isthe time florets begin to brown and aboutAinch long, grayish white, plump,turn downward. Overwintering adults wrinkled, with a small, dark head. Thelive until late summer and continue to larva is found inside the seed pod. lay eggs as successive blooms appear. Larvae develop by feeding on the new- Host plants ly formed seeds. Each larva feeds for The clover seed weevil attacks whiteapproximately 2 weeks before it drops clover, alsike clover, and Ladino clover.to the ground to pupate in an earthen It is present in all seed-producing areascell. Approximately 6 weeks elapse be- of the state. tween the time eggs are laid and the

16 new generation of weevils emerges from the soil. When the clover dries in the fall, these weevils hibernate.

Damage Adults do some damage by feeding on the base of florets in the spring and on the developing seed pods in late summer and fall. Most of the damage is caused by larvae feeding on devel- oping seeds. Each larva damages from Seed damaged by the Clover Seed Weevil. two to four seeds in each pod. Dam- aged seeds may have holes through theControl seed or be partially consumed depend- DDT as a dust or spray is suggested ing on the hardness of the seed whenfor control of the clover seed weevil attacked. This damage is frequently notadult. Dust is applied at the rate of 20 noticed by growers since the seeds arepounds of 5 per cent DDT dust per light and most of them are blown outacre, and spray at the rate of 1 pound at harvest. of actual DDT per acre. In those areas in which a good lygus bug control pro- gram is followed, the seed weevil is usually controlled. Timing of applica- tion is very important. Treatment must be delayed until the majority of the weevils are out of hibernation, but be- fore many eggs are laid. This is rough- ly about the time 20% of the first set of blooms have withered and turned brown. The percentage of brown heads can be determined by selecting small areas in the field and counting the brown heads and the heads infull bloom. It may be necessary to apply a second application if the flight from hibernationisdelayed or continued over a long period. Since these insects are small and not easily seen, growers CLOVER SEED WEEVIL. Adult actual size and will find it necessary to make frequent enlarged. Note side view of head showing checks during the early bloom period weevil beak. with an insect net.

17 Cutworms Family Phalaenidae (Noctuidae) Description September. They mate, and soon after Cutworms are the larvae of the dull-the female moths begin to lay eggs. colored, night flying moths often re-Each female lays from 200 to 500 or ferred to as "millers." The larvae varymore eggs in fields on or near the food in appearance according tospecies.plants of the larvae. These eggs hatch They are smooth,soft-bodied, andwithin a few days. In most of the when mature about to 14 inches inspecies there is but one generation a length. They may be brown or dullyear. gray in color. Some are spotted andDamage others striped. Cutworms usually feed in the late evening or at night, cutting off younger plants near the surface or feeding on the foliage of older plants. During the day cutworms often remain hidden beneath the soil surface. Early season injuryissometimes confused with winter damage. Some species of cut- worms feed primarily on weeds, such as dandelion and mustard. If you find cutworms in your field, check to see if they are damaging the crop before applying control measures. ADULT MOTH. Actual size. Larva, commonly called cutworm, actual size. Control Several insecticides may be applied as dusts or sprays to control cutworms. Host plants These will be effective only when cut- Cutworms occur in all parts of Ore-worms are feeding above ground. Irri- gon. They feed on many plants and aregation will often bring cutworms to the frequently serious pests of vegetables,surface, and insecticides should be ap- fruits, and hops as well as the legumeplied as soon after irrigation as pos- seed crops. They have caused serious sible. damage to clover, alfalfa, and peas. Cutworms that feed above ground can also be controlled with poisoned Life history baits. Moistened bran baits containing Most cutworms spend the winter as3 per cent toxaphene or 4 per cent eggs or partly grown larvae in the soil,sodium fluosilicate have been recom- under debris, or in clumps of grass.mended for cutworm control. Baits are Some species overwinter as pupae inmost effective when applied late in the the soil. The overwintering larvae re-afternoon or early evening when cut- sume feeding early in the spring andworms begin to feed. Sprays and dusts reach maturity during April, May, andhave been a more dependable means of early June. Larvae pupate in earthencontrolling most species of cutworms cells.Moths emerge from June toand are replacing baits in Oregon.

18 If cutworms are suspected at seedingWillamette Valley and other areas, time, work DDT or toxaphene into theboth DDT and toxaphene have given top inch or two of soil during seedbedgood control of several species of cut- preparation. This treatment will reduceworms, including the variegated cut- seedling damage. worm, Peridroma rnargaritosa, and the In eastern Oregon the army cut-greasy or black cutworm, Agrotis ypsi- worm,Chorizagrotisauxiliaris,haslon. Either of these insecticides may be been effectively controlled with baits.applied as a spray or a dust. Apply 20 In central Oregon, toxaphene has beenpounds of 10 per cent dust per acre, effective in controlling the red-backedor 2 pounds of actual DDT or toxa- cutworm, Euxoa ochrogaster. In thephene per acre as a spray.

Field Crickets Gryllus assimilus (Fabr.) The common field cricket can be- come abundant in late summer and attack legume seed crops. Adults open the seed pods and feed upon the de- veloping seeds. The spray or dust pro- gram suggested for grasshoppers will control the field cricket.

FIELD CRICKET. Actual size and enlarged.

Grasshoppers Family Acrididae Description femur rubrum, are common inle- There are many species of grass-gumes. The clear-winged or warrior hoppers in Oregon, but only a few dograsshopper, Camnula pellucida, adapts much damage to legumes. The migra-itself to many conditions, but is most tory grasshopper, Melano plus mexi-frequently found in improved pastures canus, is the most widespread and mayor well-sodded meadows. One of the cause serious damage to crops as wellslant-faced grasshoppers, Chorthip pus as rangeland. The two-striped grass-longicornis, occasionally causes serious hopper, Melano plus bivittatus, and theinjury to grass seed crops in western red-leggedgrasshopper,Melano plusOregon.

19 Host plants Many crops can be seriously dam- aged by grasshoppers. Of the legumes grown in Oregon, clover and alfalfa, particularly alfalfa seed, are susceptible to injury. Damage to range grasses can be serious, and may reduce the carry- GRASSHOPPER. Adult actual size. ing capacity of rangeland and expose the soil to erosion. Grasshoppers areControl common in most parts of the state, but Grasshoppers are easiest to kill when are of the greatest importance in east-they are immature and before they ern Oregon. have developed wings. It is often pos- sible to kill tremendous numbers of grasshoppersbytreatingrelatively small areas if insecticides are applied Life history before grasshoppers scatter from their In Oregon, grasshoppers have aegg beds or from ditch banks and single generation each year. The fe-fence rows into the fields. Where there male grasshopper lays its eggs in theis the possibility of extensive grass- soil during the summer or early fall.hopper outbreaks involving rangeland, These eggs are enclosed in pods. Thefarmers frequently finditadvanta- number of eggs in each pod varies withgeous to cooperate with the U.S.D.A. the species. Clear-winged grasshoppersin their control work. County extension congregate to lay their eggs in "beds"agents can be of great help to farmers in sod or meadow land. The migratoryand ranchers in planning their control and the red-legged grasshoppers do notprogram. concentrate to lay their eggs but prefer Grasshoppers can be controlled with to lay them throughout legume fields orseveral insecticides applied as either other uncultivatedcrops. Migratorydusts or sprays. Sprays are usually grasshoppers often lay eggs through-somewhat more effective and cheaper. out rangeland from which the offspringWhere thefoliage being treatedis may migrate intocrops. The two-dense, a heavier amount per acre is striped grasshopper may lay eggs with-suggested. Toxaphene is preferred for in cropped fields, but prefers sod orapplications to legume crops in bloom weedy ground along ditch banks andbecause itisless hazardous to bees fence rows. than other commonly used insecticides.

TABLE 3. SUGGESTED RATES OF INSECTICIDE APPLICATION FOR GRASSHOPPERS

Amount per acre Insecticide Spray Dust Aldrin 2-3 ozs. (actual) 20-25 lbs.1% Chlordane /4 lb. (actual) 20-30 lbs.5% Heptachlor 3-4 ozs. (actual) 10-15 lbs. 21% Toxaphene 1-11 lbs. (actual) 15-20 lbs. 10%

20 Ladino Clover Seed Midge Dasyneura gentneri Pritchard Description overwinter intiny cocoons, become This midge, except for food habits,active with the first blooming of the resembles the cloverflower midge,clover, and produce several genera- Dasyneura leguminicola. tions before cool, fall weather. Host plants Damage Ladino and alsikeclover are the There is no visible damage to blos- principal host plans for the Ladinosoms as described for clover flower clover flower midge. It does not attackmidge. Afflicted florets appear normal red clover. This is a new pest and hasexcept they do not produce seed. The been found in central and southerntiny maggots suck juices from the Oregon. developingseedsand preventseed formation. Life history Except for host plants the life his-Control tory is very similar to that described There is no suggested control for for the clover flower midge. Theythis midge.

Leafhoppers Family Cicadellidae (several species) Leafhoppersareslenderinsects,reduce seed production. Several species usually less than / inch long, commonlyare capable of transmitting virus dis- found in legume seedfields.Mosteases. The amount of damage leafhop- speciesaregreenor brown withpers do to legumes in Oregon has not colored spots or lines on the wings andbeenestablished.Methoxychloror back. They hop when disturbed. HighDDT have been effective in controlling populations may devitalize plants andthem.

Lesser Clover Leaf Weevil Hypera nigrirostris (Fabr.) Description Adults are about inch long, green in color with two dark bands behind the head. The head is brown to black with a long, slender, black beak. Larvae are aboutIinch long, dirty white to yellowish green in color, with a faint stripe down the back.

LESSER CLOVER LEAF WEEVIIL. Adult actual size and enlarged.

21 Host plants Damage Although this weevil will attack sev- Damage is caused by larvae feeding eral clovers, it is principally a pest onin early spring on buds and unfolding red clover and alsike clover. It is foundleaves. They tunnel into the stems and in all seed-producing areas of the state.cause the plant above the injury to wilt and die. Plants usually recover from Life history early injury and show very little evi- Adults overwinter around the basedence of damage. When infestations of clover plants or under grass andare heavy or occur late in the spring, debris near clover fields. They becomeseed yield may be reduced if plants active and lay eggs in the buds of thecannot produce enough new growth to plant or in slits cut into the stem aboutrecover from injury. Adults feed on the time clover growth starts in theclover leaves but do not cause serious damage to plants. spring.Larvaefeed on thefolded tender /eaves, buds, and stems of theControl plant. They feed for about 3 weeks,_ There is no chemical control. It is spin a cocoon, and pupate on the plantdifficulttocontactlarvaeprotected or on the ground. New adults emergewithin the plant parts. If infestations in late June and early July. There isare observed early in the season, it is one generation a year. sometimes practical to clip the crop and destroy larvae and unhatched eggs.

Lygus Bugs Lygus spp. (several species) Description A combination lygus bug and clover Adults are about 3/16 inch long.seed weevil control is suggested for Lygus bugs vary in color from yellow-alsike clover. Lygus bugs are present ish-green to reddish or dark brown.inall areas of the state.They are The presence of a light yellowish V-found in the greatest numbers in irri- shaped mark on the back (see illustra-gated areas. tion) of the adult is helpful in distin-Life history guishing lygus bugs from other insects. Lygus bugs overwinter as adults, in Nymphs are wingless and frequentlyor near the fields, under plants, and mistaken for aphids in the field. Theyfield debris. In early spring they re- can be distinguished from aphids bysume activity during warm, mild days, their sturdier bodies and ability tolaying eggs in plant tissue, usually in move about rapidly. There are severalthe terminal growth. The development species of lygus bugs in Oregon. period from egg to adult requires about 6 weeks. There are several generations Host plants produced each season. When hay fields Lygus bugs have an extremely wideare cut or seed fields become dry, lygus range of host plants. They are not con-bugs migrate to fields in which there is sidered a pest on all legume seedcrops.attractive,green growth. They are In Oregon, a control is suggested foractive in the field until cold weather alfalfa and Ladino clover seedcrops.forces them into hibernation. 22 Damage able of causing shriveled seed or pre- Lygus bugs feed by sucking juicesventing the formation of seed. from the plant. Nymphs feed more It has not been possible to demon- actively than adults and are believedstrate that the usual populations of to do the most damage. The injury theylygus bugs are capable of decreasing cause varies with the crop. seed yields of red clover. The extent The feeding of lygus bugs on alfalfato which lygus bugs affect seed produc- kills the buds and prevents the forma-tion of other legumes has not been tion of seed. They may attack flowersestablished. and cause them to drop, or feed on theControl developing seed pods and cause shriv- An application during the bud stage eled seed. There is no conspicuousbefore pollinators are activeissug- damage, such as bud killing or flowergested in alfalfa seed fields. This treat- drop in Ladino clover. By withdrawingment will prevent a large population of juices from the productive portion oflygus bugs in the first bloom. A second the Ladino plant, these insects are cap-application is necessary in the bloom stage of alfalfa if lygus bug counts average one insect (adult or nymph) per sweep of an insect net. In Ladino clover seed fields, one treatment usually suffices. This applica- tion is made during the bloom stage when lygus bugs average one per sweep. If possible, delay treating seed fieldsuntil adjacent hay fields have LYGUS BUGS. (A) Early instar nymph. Note been cut. Lygus bugs will migrate from resemblance to aphid. drying hay fields into seed fields.

(B) Later instar nymph with wing pads. (C) Adult, actual size, and enlarged.

23 Apply insecticides in early morningsome instances because it is less toxic or late evening to avoid killing pollinat-to pollinating insects and is more toxic ing insects. Toxaphene is preferred into grasshoppers than DDT.

TABLE 4. SUGGESTED RATES OF INSECTICIDE APPLICATION FOR LYGUS BUGS Amount per acre Spray Dust Alfalfa Bud stage control DDT 2 lbs. (actual) 20 lbs. 10% Alfalfa or Ladino clover Flower stage application DDT lbs. (actual) 30 lbs.5% Toxaphene* 2lbs. (actual) 20 lbs. 10% * If grasshoppers are present, toxaphene is preferred.

Meadow Spittlebug Philaenus leucophthalmus (L.) Spittlebugs have become an import-termined. ant pest of legumes in central and east- The feeding of young spittlebugs ern United States during the past 10stunts the plants and reduces hay yields. years. This insect is present in abund-In the central and eastern states spring ance in western Oregon. It may betreatment with toxaphene, methoxy- causing some damage to alfalfa, clover,chlor,benzenehexachloride,hepta- and birdsfoot trefoil (lotus), but thechlor, or lindane is used to control this extent of this damage has not been de-insect.

Nitidulid Beetle Meligethes seminulum Lec. Description Host plants In Oregon, this insect is called the Nitidulid beetles are found inall nitidulid beetle or black pollen beetle.flowers from early spring until late Adults are small, black,oval, shinysummer. In seed crops they are a pest beetles about 3/32 inch long. A helpfulto red clover and irrigated Ladino characterinseparating them fromclover. They are found throughout other small beetles is the presence of aOregon, but are a pest only in the small knob or club at the tip of theWillamette Valley. antennae. Larvae are yellowish-white with three lines of dark spots runningLife history down the back. When full grown, lar- These insects overwinter as adults vae are aboutinch long. in field borders and plant debris. They

24 seed production. Adults, because of their large numbers and activities in seeking pollen, damage the developing florets of clover in July and August. Buds are attacked as soon as the florets show color, and these damaged flowers fail to produce seed. Damaged buds and flowers are brown and unattractive to pollinating insects. Since red clover requires insectpollination, these browned or damaged fields fail to pro- duce profitable seed crops. NITIDULID BEETLE. Adult actual size and enlarged. Control leavehibernationinearlyspring, A chemical or cultural control has March or April, and feed on the pollenbeen difficult because of the prolonged of any plants in bloom. They lay eggsemergence and migration period from in the flowers of vetch, clover, andvetch to clover. If there are only six lotus, the majority being laid in hairyto eight beetles per blossom, one appli- vetch. Larvae feed for approximately 3 weeks on the pollen of their hostcation of toxaphene has given adequate plant, then drop to the soil to pupate.control. When beetles are more abun- Around the middle of July the newdant and the migration period pro- adults emerge from thesoil. Theselonged, two or three applications of beetles form the large population thattoxaphene have reduced beetles suffi- attack the seed crop bloom of clovers.ciently to permit blossoms to develop Since vetch blooms are dry when adultsnormal color and attractpollinating emerge, they migrate from roadsideinsects. The time between applications and cultivated vetch into nearby cloverdepends on the extent to which beetles fields. Beetles remain in the fields untilmigrate back into the field following mid-August. treatment. Apply 25 pounds of 10 per Damage cent toxaphene dust per acre or 2 to 2i Larvae feed in the florets on pollenpounds of actual toxaphene per acre of vetch and clover but do not affectas a spray.

Omnivorous Leaf Tier Cnephasia longana (Haw.) Larvae of this moth attack manyand feed upon the terminal growth. It agricultural crops. They are called "tieis doubtful if this insect reduces seed worms" when they attack commonyields. Attempts to control it have not vetch. Larvae web the terminal leavesbeen successful.

25 Pea Aphid Macrosiphum pisi (Kalt.) Description The pea aphid is a small, light green, soft-bodied insect about 3/16 of an inch long. Except for size, adults and youngaresimilarinappearance. Adults may be either winged or wing- less.

PEA APHID. Adult, actual size and enlarged.

In western Oregon, pea aphids over- WINGLESS NYMPH winter as adults and probably to some extent in the egg stage. Overwintering Host plants adults may be found on alfalfa, clover, The pea is the preferred food plant.and Scotch broom, but those which Alfalfa and vetch are other favoredoverwinter on fall sown legumes con- food plants and occasionally are ser-tribute the most to aphid outbreaks. iouslydamaged.AlthoughseveralWinter weather conditions greatly in- kinds of clover, including red, alsike,fluence aphid abundance in western crimson, and sweet clover are fed uponOregon.Data gathered byfederal by the pea aphid, they are seldom dam-entomologists show aphid outbreaks aged to any serious degree. The peado not occur on fall sown legumes aphid is found throughout Oregon, butwhen the minimum temperature falls is a serious pest only where peas arebelow 15° F. or when the mean tem- grown extensively. perature for any 7- to 8-day period is 31° F. or less. Life history In eastern Oregon, the pea aphidDamage overwinters in the egg stage on alfalfa The pea aphid damages peas by and clover. The overwintering eggssucking plant juices from leaves, stems, hatch into wingless young or nymphs.blossoms, and pods, and causes the When mature, these are called stemplant to have a wilted and stunted ap- mothers. These stem mothers producepearance. Because of its ability to re- living young. When mature, some ofproduce rapidly under favorable wea- these may fly to other legume cropsther conditions, tremendous numbers where they can produce as manyas 10may build up in a relatively short time. to 15 generations a year. In the lateThe pea aphids are capable of trans- summer or fall aphids migrate to alf-mitting virus diseases to legumes. Loss alfa and clover fields where. theover-due to virus disease may be very severe wintering eggs are laid. even though aphids are not abundant.

26 Control and damage is noted, it is desirable to control them. The damage aphids might do is diffi- Sprays have been more effective cult to predict. Frequently parasites,than dusts. Airplane dusting has been predators, and adverse weather keepless effective than ground dusting, but aphidpopulationsbelowdamagingairplane spraying is effective if 4 to 5 numbers. When aphids are abundantgallons of liquid per acre are applied.

TABLE 5. SUGGESTED RATES OF INSECTICIDE APPLICATION FOR PEA APHIDS

Amount per acre Insecticide Spray Dust Parathion 6 to 8 ozs. (actual) 35 lbs. 1% Mal athion 1 lb. (actual) TEPP 6 ozs. (actual) 35 lbs. 1%

Pea Leaf Weevil Sitona lineata L. This insect was first found in Ore-enough to determine ifit will be a gon in 1951. This weevil is similar inserious pest. If control is needed, DDT appearance to the clover root curculio.at the rate of 1 pound actual material It has been observed to feed on peaper acre is reported as being effective and red clover foliage. This insect hasagainst adult weevils. not been abundant in Oregon long

Pea Weevil Bruchus pisorum (L.) Description The adult pea weevilisa small, grayish-brown beetle about 1/5 inch long and marked with dark and light spots. The full grown larva is about inch long. It is crescent shaped and white or cream colored.

Host plants Cultivated peas are the only plants attacked. The pea weevil is found in all areas of the state. PEA WEEVIL. Adult, actual size and enlarged.

27 Life history Control Pea weevils spend the winter in the Proper timing of insecticide appli- adult stage in protected places. Beetlescation is important. It should be re- begin leavingtheir winter quartersmembered that insecticides are applied about the time the first peas begin toto kill adult weevils before they lay blossom. They feed on pea flowers,eggs. Once eggs are laid on pods, it is mate, and by the time pods form, ortoo late to prevent weevily peas. Sprays shortlyafter,females beginlayingor dusts should be applied soon after orange-colored eggs on the pods. the first pods appear and before eggs Upon hatching, young larvae boreare laid. Apply 20 pounds of 5% DDT through the pods and enter the seeds.dust per acre, or 1 pound of actual Larvae feed and develop inside seeds.DDT per acre in a spray. Both pea The period of larval development isweevils and pea aphids may be con- from 4 to 8 weeks. Mature larvaetrolled with parathion or malathion. transform into the pupal stage andHowever, DDT is more effective if then change to the adult stage withinweevils are the only problem. This the seeds. If the seed is stored in acombined control is suggested only if cool, dry place, adult weevils may re-aphid control can be delayed until pods main inside the seeds until the follow-appear. ing spring.Usually, however, they Only those portions of the field ac- leave the seeds and seek suitable hiber-tuallyinfested need tobetreated. nation places. There is one generationExtent of the infestation within a field a year. may be determined by sweeping with Damage an insect net. In the case of smaller The pea weevil is the most importantfields of 10 acres or less, it will usually insect pest of peas in Oregon andbe necessary to dust the entire field. should be controlledin most areas Austrian winter field peas should be where peas are raised. Larvae feedingfumigated promptly after harvest to within the seed destroy or greatly im-kill any larvae in the seed before they pair its viability. impair germination.

Slugs Description Host plants Slugs are notinsects.They are Slugs will attack almost all crops. closely related to snails, clams, oysters,In western Oregon they frequently and similar animals. There are severaldamage legume seedlings and may in- species of slugs in Oregon, but thejure older plants in hay and seed fields most common pest in legume fields isand pastures. the gray garden slug, Derocerus reti- culatum (Muller). They vary in colorLife history from black to gray and are usually Slugs overwinter inallstages of flecked or mottled with brown spots. developmentinprotected placesor Newly hatched slugs are only about cracks in the soil. They are active dur- inch long, and when full grown areing mild moist weather and are inactive several inches long. during warm, dry, or freezing weather.

28 Slugs feed and are active at night or onor permanent pastures. Slug damage dark cloudy days. Slugs are bisexual,is distinctive and may be identified by that is each individual slug is capablethe irregular-shaped feeding holes in of laying eggs. Eggs are pearly whitethe leaves or the dried mucus trails and about the same size and shape aswhere the slugs have traveled. a BB shot. They are laid in small masses under field debris or in cracks Control in the soil. The period of development Slugs are difficult to control. A bait from egg to adult depends on the wea-containing metaldehyde as an attractant ther, but is less than 3 months underand calcium arsenate as a poison is the favorable conditions.Slugs are ex-most practical method of control. How- tremely well adapted to withstand pro-ever, unless conditions are favorable, longed periods of starvation or adverseit is not always possible to obtain satis- temperature conditions. factory control. Commercially prepared baits in a pellet form containing at least 3% metaldehydearerecom- mended for field applications. Apply bait in late afternoon during cloudy, cool weather. Since rain breaks down the bait, avoid treatment during Typical slug. periods of heavy rainfall. It is possible only a portion of a field will be in- fested. Infested areas may be deter- Damage mined by test-baiting the field and In newly seeded legume fields, seed-making application in the areas slugs ling plants are often destroyed com-are found. To test-bait, place a dozen pletely. It is advisable for growers toorsopelletsatseverallocations examine for slug damage as seedlingsthroughout the field. Mark these loca- are emerging. A stand may be serious-tions. Examine the baits after 24 hours ly damaged or destroyed in a few days.and if two or more dead slugs are During periods of mild weather theyI ound at a bait station, you would be may kill or retard the growth of le-justified in baiting that portion of the gume plants in established seed fields field.

TABLE 6. SUGGESTED RATES OF BAIT APPLICATION FOR SLUGS

Newly seeded legume fields Amount per acre Test-bait before seeds sprout to determine if slugs are in field or fence rows. 4-5 pounds Bait if slugs are present or damaging seedlings. A second application may be necessary if damage continues in seedlings. 4-5 pounds Established fields or pastures Test-bait for areas of infestation or bait when damage is noted. A second application is usually necessary. Eggs laid before baiting will10 pounds or more hatch and slugs will reinf est the fields. Under some conditions, appli- per acre per cations have been necessary in the fall and again in the spring. application.

29 Spider Mites Several species Description plant or an alternate host plant. The Spider mites are not insects. Theyclover spider mite frequently over- are tiny eight-legged animals less thanwinters in and around homes and may 3/100 inchlong,closelyrelatedtobecome a household pest. spiders and ticks. Because of their ex- Eggs, nymphs, and adults may be tremely small size they are usuallyfound on the underside of the same recognized in the field by their damageleaf. Some species spin fine webbing rather than by their appearance. Thereon the leaf or may web several leaves, are several species of spider mites inor leaves and blossoms, together'. They legume crops in Oregon. One of theremain on the plants until the crop is most common is the Atlantic spiderharvested or cold weather forces them mite, Tetranychus atlanticus.Othersinto hibernation. found on legumes are the two-spotted mite, Tetranychus bimaculatus and the clover spider mite, Bryobia praetiosa

SPIDER MITES. A colony of spider mites on the underside of a clover leaf.

Host plants The clover spider mite greatly enlarged. Spider mites attack many plants. In central and eastern Oregon they are most abundant on alfalfa, red clover, Damage and Ladino clover. Spider mites damage a plant by sucking juices from the leaves. Early Life history in the season infested leaves have a The lifehistory of spider mitesmottled appearance. In late summer varies with different species. They mayleaves appear dry and browned. In overwinterasadultsinprotectedsevere infestations leaves and blossoms places, or as eggs on either the hostmay be webbed, the plants withered or

30 burned inappearance. Poor standsControl appear to suffer more than vigorously Further information is needed on growing stands. Frequently parts of athe effectiveness of the various miti- field, such as borders or dry areas,cides, the timing and method of appli- appear more severely damaged. cation, and benefit to seed production The extent to which these spiderbefore a control program can be sug- mites are capable of affecting seed pro-gested. duction has not been established. Early Some westernstatesrecommend seasoninfestations,which drythedusts and sprays of the miticide, ara- plants before the seed is set, undoubt-mite. Ground application is reported to edlydecreaseyields.Observationsbe more effective than airplane applica- indicate late season infestations maytion, and dusts more effective than not seriously affect seed production. sprays. These states suggest applying 20 pounds of 3% or aramite dust per acre, or 3 to 4 quarts of emulsifi- able concentrate in 25 gallons of water per acre. It is possible to combine ara- mite with DDT or toxaphene for lygus bug and spider mite control. A number of miticides have been tested on red clover. The most effective of these has been Systox (demeton) applied by ground sprayer at the rates of 2, 4, or 6 ounces of actual material in 20 gallons of water per acre. In the experimental work however, it has not beenpossibletodemonstratethat spider mite control has increased seed A common spider mite greatly enlarged. yields.

Sweetclover Weevil Sitona cylindricollis Fahr. This insect was first found in eastern lb. actual material per acre are re- Oregon in 1954. In other areas of theported to be effective in controlling United Statesitis a pest to sweet-adultweevils.Applications may be clover and alfalfa seedlings. It has beenmade in the spring when overwintering found in Oregon on Ladino clover andadults migrate into new plantings, or in alfalfa. The adult is similar in appear-midsummer when new weevil adults ance to the clover root curculio. Hepta-emerge from old stands. chlor or dieldrin applied at the rate of

3] Thrips Frankliniella spp. Description when legume plants begin their growth Thrips are small insects rarely moreand migrate to new fields about bloom- than 1/10 inch long. They are slender,ing time. Eggs are laid in the floral quick moving, and scarcely visible toparts and on leaves. There are several the unaided eye. Nymphs resemblegenerations produced each season until adults but are smaller and wingless. cold weather or drying fieldsforce them into inactivity. Under favorable Host plants weather conditions there is probably a Thrips are found in the flowers ofnew generation every 2 weeks. all legumes. They are present in all seed-producing areas of Oregon. Damage Thrips cause damage to many agri- cultural crops. It is quite possible they are responsible for some of the dis- colored or withered flowers in legume plants. They have sucking mouth parts and suck juices from the plant cells. These damaged cells, when dry, give the plant a discolored appearance. Control Almost all control programs for in- jurious insects on legume crops also control thrips to some extent. These applications are most frequently made THRIPS. Adult actual size and enlarged. in late spring or summer after thrips Wingless nymph. are established in the fields. The con- trol may reduce them for a short Life history period until another generation hatches Thrips overwinter in the adult stagefrom the eggs. Predators frequently in grass and field trash near the soilreduce the number of thrips in the seed surface. They usually appear in springfields.

Vetch Weevil Bruchus brachialis Fabr. Description Host plants The vetch weevil is a small, dark- The vetch weevil infests seeds of colored beetle about inch long. Thiswoolypod vetch, purple vetch, hairy insectisalso known as the vetchvetch, and smooth vetch. It does not bruchid. It resembles the pea weevil,attack the seed of Willamette or com- but is only about half as large. Themon vetch. It is found in all hairy full-grown larvaislight, or cream-vetch seed-producing areas. colored, and slightly less thanIinch long.

32 early September. There is one genera- tion a year. Damage Larvae ofthe vetch weevil feed within the developing seeds, destroying their viability and commercial value. The seed loss in untreated fields is fre- quently 50 per cent or more. Control Insecticides are applied to kill the VETCH WEEVIL. Adult actual size and enlarged. adult weevils before they have an ap- portunity to lay eggs. It is important, therefore,that these applications be Life history made when the first pods appear. Dust The adult weevil spends the winterwith 20 pounds of 5% DDT per acre, in protected places under loose bark,or apply DDT spray at the rateof 1 lichens on trees, or cracks in fencepound of actual DDT in 3 to 5 gallons posts and buildings. Adults emergeof liquid per acre. It may be possible during the first warm days of spring,to combine vetch weevil and peaaphid usuallyinApril,and continuetocontrol in a single application with the emerge on favorable days during May.addition of a phosphate insecticide in Weevils begin to lay eggs as soonthe DDT spray. as the first pods appear. Eggs are glued Vetch weevils are able to fly a con- to the outside of pods. They are elong-siderable distance. Vetch grown for ate oval in shape, whitish in color, andhay and adjacent to seed fields should about 1/50 inch long. The larvae hatch-be cut before treating the seed field ing from these eggs bore through thefor vetch weevil control. Make applica- pod and into the developing seeds.tion in early morning or late evening Larvae develop within the seeds andto reduce the possibility of killingpol- emerge as adults during August andlinating insects.

Western Spotted Cucumber Beetle Diabrotica undecimpunctata Mann. Description larvaeareyollowish-white and are This beetleisalso known as theaboutIinch long. 11-spottedor12-spotted cucumber beetle. Adults are about + inch long and Host plants are frequently mistaken for one of the The western spotted cucumber beetle beneficial ladybird beedles. The long, isa general feeder and has awide conspicuous, thread-like antennae are arange of agricultural host plants.It helpful character in separating themfrequently damages red clover and from ladybird beetles. The westernother seedling legumes in early spring. spotted cucumber beetles are yellowish-It occurs in western Oregon and is not green with eleven blackspots. Thefound east of the Cascade Mountains. 33 and thefirstgeneration ofadults emerges in late June and July. These adultsproduce ageneration which emerges in early fall and remains active in the field until cold weather forces them into hibernation. Adults, then, are active in the field from the first warm weather of spring until the first cold weather in the fall, and during periods of mild weather during the winter.

Damage Damage occurs in early spring to

WESTERN SPOTTED CUCUMBER BEETLE. seedling red clover and other legumes. Adult actual size and enlarged. Adults feed on tender leaflets of these plants and either destroy or retard the growth of seedlings. Since this damage Life history may take place in a very few days, it is Winter is passed in the adult stageimportant that fields be checked during under debris in fence rows or in thethe warm days of early spring. fields. They may become active and Frequently large numbers of adults feed during periods of mild sunnymigrate into blooming fields during the weather in the winter. In early springsummer and may cause considerable they become active, feed, and depositdamage.Undersuchcircumstances their eggs in the soil. Larvae feed ongrowers may find it necessary to apply the roots of plants, pupate in the soil,control measures.

TABLE 7. SUGGESTED RATES OF INSECTICIDE APPLICATIONFOR CUCUMBER BEETLE

Adult control Amount peracre early spring when beetles present Spray Dust DDT 1 lb. (actual) 20 lbs. 5% Methoxychlor 1 lb. (actual) 20 lbs. 5% Toxaphene lbs. (actual) 15-20 lbs. 10%

34 em$datTotuce4 C OME INSECTSare essential as pollin- Another group of insects beneficial ators of legume seed crops. Bum-to seed producers includes predators blebees, wild solitary bees, and honeyand parasites. This group attacks in- bees are all recognized as beneficialjurious insects and helps keep them in insects and necessary to seed produc-check. Beneficial insects may be con- tion. Recognition of pollinating insectsfused with injurious insects. It will be and handling of bees comprise a fieldof interest and helpful to growers to in itself and will not be discussed inrecognize these insects. Some of the this bulletin. It is important that anymost common predators and parasites control program protect these insectsfound in your fields are included in as much as possible. this section.

Damsel Bugs Family Nabidae These predacious insects are called damsel bugs or nabids. They are pale gray incolor. Because of the long narrow body they resemble none of the injurious insects found in the field. They feed on aphids,leafhoppers, caterpillars, and other soft-bodied in- sects.

DAMSEL BUG. Adult actual size and enlarged.

Geocorus Bugs Family Lygaeidae These insects have no common name other than big-eyed bugs. They are similar in shape to lygus bugs and are frequently mistaken for this insect in the field. They are smaller and less dis- tinctly colored than lygus bugs. Nymphs and adults feed on aphids, thrips, and other soft-bodied insects. Suggested rates of DDT, and to some extent chlordane and toxaphene, do not seriously reduce the numbers of these GEOCORUS BUG. Adult, actual size beneficial predators in the field. and enlarged.

35 Lacewings Family Chrysopidae Lacewings are light green with deli- cate lace-like wings and golden eyes. When crushed they have a disagreeable odor. Adults do not feed. Larvae are called aphis-lions because they feed on aphids and other soft-bodied insects. They are grayish or yellowish with red or brown markings, flat, tapered at each end, and have long curved jaws with which they pierce their host and ex- tract the body juices. Lacewings de- posit their eggs on silken stalks so the first hatched will not devour there- maining brood.

LACEWING. Adult, actual size and enlarged.

Ladybird Beetles Family Cocci nelli dae Ladybird beetles or "lady bugs" are common insects and easily recognized. They vary in color and size, but are usually aroundIinch long and red or yellow with black spots. Larvae are also brightly colored and not easily confused with other larvae in the field. Ladybird beetles in both the adult and larvae stage feed on soft-bodied insects. They are particularly effective in controlling aphids on legume plants.

LARVA, feeding on an aphid.

One species, Stethorus pictipes, a small - shiny-black ladybird beetle is an im- portant predator on spider mites. It has been estimated that each larva consumes over 25 aphids per day and each adult over 50 aphids per day. Un- fortunately these insects are also killed with almost all the suggested control LADYBIRD BEETLE. Actual size and enlarged. programs for injurious insects.

36 Minute Pirate Bug Family Anthocoridae This tiny insect has no generally accepted common name. It belongs to a group sometimes called minute pirate bugs and is frequently called onus, a name derived from its scientific name, Onus tristicolor. These insects are only inch long and the smallest of the common preda- tors. They feed as nymphs and adults on insect eggs, aphids, thrips, and other soft-bodied insects. They can be easily recognized by theirsmallsize and characteristic black and white color pattern. Nymphs are amber colored and wingless. These insects are not killed by the suggested rates of DDT. MINUTE PIRATE BUG. Adult, actual size and enlarged.

Parasitic Insects Some Families of Wasps and Flies

whereas predators attack many insects in their development. They lay eggs on or near the intended victim and the parasitic larvae develop by feeding on the host. The host is not killed at first, but will usually live long enough to permit the parasite's development. Parasites are mostly small wasp-like insects which are rarely seen by grow- 4tg ers. Parasitized insects are frequently conspicuous enough to be observed. Typical parasite. They are usually swollen, immobile, and if the parasite has matured, the host iscompletely hollow. Although Parasites form a large group of in-parasites do not attract as much atten- sects which differ in habits from thetion as predators, under favorable con- predators. Each parasite normally de-ditions they are more effective in con- velops on one insect or insect egg,trolling insects.

37 Syrphid Flies Family Syrphidae

SYRPHID FLY. Adult, actual size and enlarged.

These insects are also called hover flies or drone flies. Adults are brightly colored and mimic bees in their ap- pearance and habitoffrequenting flowers. It is possible they are helpful in pollination. They vary in size and color but can be recognized by their bee-like appearance. LARVA, feeding on aphid. The larvae are slug-like maggots and usually are dull green to yellow inThey are blind and loop around in color, variable in size, often having asearch of prey. The larvae are killed by stripe down the back. They feed onmost insecticides applied to control in- aphids and other soft-bodied insects.jurious insects.

38 Protect Bees

Bees are essential to the production of most legume seeds. To avoid killing them, follow these precautions :

If possible, avoid applying insecticides when the field is in bloom. If applications are necessary during the blooming period, do not make them during the day when bees are active.

Toxaphene is probably the least poisonous to bees and is preferred if application is necessary during the bloom period.

Apply insecticides only at the suggested rates of appli- cation.

If you are renting bees, discuss your insect control plans with the beekeeper. If bees are near your fields, let the beekeeper know when you plan to apply insecticides so he can move the bees if he wishes.