Extension Bulletin 773 March 1958

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FEDERAL COOPERATIVE EXTENSION SERVICE e OREGON STATE COLLEGE CORVALLIS Cooperative Extension work in Agriculture and Home Economics, F. E. Price, director. Oregon State College and the United States Department of Agriculture cooperating. Printed and distributed in furtherance of Acts of Congress of May 8 and June 30, 1914. Extension Bulletin 773 March 1958 Contents Page Ambrosia Beetle 4 Apple Mealybug 4 Filbert Aphid 5 Filbert Bud Mite 6 Filbert Leaf roller 7 Polyphemus Moth 8 Filbertworm 9 Omniverous Leaf Tier 12 Filbert Nut Weevil 13 Small Gray Leaf Weevil 14 Tree Crickets 14 Tingids 15 Eye-Spotted Bud Moth 16

2 Apply Pesticides Thoroughly--at the Right Time Insect control is becoming increas-their dense foliage. Dusts should be ingly important in the growing of fil-applied when there is no wind. Early berts in Oregon. Insect pests destroymorning is a good time to apply dusts, nuts, devitalize trees, reduce nut yieldbut many growers have found that and quality. It is helpful if growers candust can be appliedsuccessfully at recognize insect pests which are in- night. jurious to filberts. About 8 gallons of spray are re- To control many of the pests it isquired to cover thoroughly a medium important to apply sprays or dusts atsized filbert tree, using the bulk method the right time. Notices for control ofof spraying, with a hand spray gun filbert moth and filbert leaf roller areand high pressure sprayer. Spray rec- sentto growers by county agents.ommendations in this bulletin are based Those who wish to receive these no-on the bulk methodpounds of insec- tices should request their county agentsticide per 100 gallons of water. With to include their names on the mailingair-carriersprayerssomewhatless lists. liquid per acre can be used, but ap- Thorough application of insecticidesproximately the same amount of in- is especially important in the controlsecticide per acre is required. Tractor of filbert insect pests since filberts arespeeds should not exceed 2 miles per difficult to spray or dust because ofhour while spraying.

Use Pesticides Safely Parathion is suggested for the control of several insect pests of filberts. It is a highly toxic insecticide. Growers who plan to use parathion should follow the manufacturer's directions.

When using any pesticide follow these precautions : Read the label carefully. Follow instructions on the label. Store out of reach of children. Dispose of containers safely.

3 Ambrosia Beetle Anisandrus pyri

Adultbeetlesareactiveduring March, April, and May. They make , burrows into the limbs or trunks of

or trees. Eggs are laid on the sides of theseburrows andalsooncross tunnels. Control Since beetles attack only trees that are in a sour sap condition, every pos- Ambrosia Beetle sible means should be used to revital- ize the trees. Heavily infested limbs and trees should be pruned and burned. Description and damage Slightlyinfestedportions may be This small, black beetle, often re-treated with a wash prepared by add- ferred to as shot-hole borer, sometimesing 1 pound of 50% wettable DDT attacks filberts. The injury is recog-powder in5gallons of water. The nized by the small shot-hole entranceswash can be most easily applied with of the beetles. This insect belongs toa large paint brush. Treating a num- the group known as Ambrosia beetles,ber of trees or large portions of them the larvae of which feed on a fungusis best done by spray. Use 2 pounds of which the beetles plant in the tunnels.50% wettable DDT powder per 100 The fungus grows only in trees thatgallons of water. have a sour sap condition." There are The wash or the spray will kill the several causes of sour sap such asadult beetles. Apply when the beetles winter injury, drought, lack of drain-are observed to be active during the age, etc. spring months. -Apple Mealybug Phenacoccus aceris Description and damage currant, hazelnut, and filbert. The in- Thisinsect,apparently native tosect feeds by sucking plant juices. It Europe, was first observed on Oregonsecretes a honeydew-like material which filberts in 1951. The apple mealybugis a good media for the growth of has been confined to a restricted areablack sooty fungus. The young feed in northern Marion County, a limitedon the leaves and tender twigs. Al- area in western Polk County, and inthough serious damage has not been 1957 was found in an orchard in north-observed, it could be anticipated that western Linn County. heavy infestations might result in pre- In Oregon this insect has only beenmature dropping of leaves and cause found on filberts. In North America itsmall twigs to die. has been reported on apple, cherry, Although not yet widespread, this

4 insect may become one of greater economic importance in future years. Life history Eggs are laid by overwintering fe- males during May. The eggs are found in masses, each containing about 500 or more eggs. In June the young start emerging from the eggs and crawl to young twigs and leaves where they feed. In the fall the nymphs migrate to the larger limbs where they spend the winter. Apple Mealybug Control Control has been necessary in onlythe young nymphs are migrating to the a few instances. Indications are thatleaves and twigs. parathion and malathion asrecom- Canadian entomologists report a 4% mended for the control of aphids aredormant oil spray has given satisfac- also effective against the nymphs oftory control of this pest. To avoid in- the apple mealybug. These sprays orjury to trees oil sprays should be ap- dusts should be applied in June whenplied before buds open. Filbert Aphid Myzocallis coryli Description and damage Control Immature aphids are of a light green Filbert aphids may be controlled by color. Mature or winged forms areapplication of malathion at the rate of darker. They feed by sucking plant2 pounds of the 25% wettable powder juices. Honeydew, which aphids se-or 1 pint 57% emulsion concentrate crete, may contribute to leaf scorch.per 100 gallons of water ; or parathion Lead arsenate dusts or sprays asap-at the rate of1 pound of the 25% plied for the control of filbert mothwettable powder per 100 gallons of may, in the presence of honeydew,water. Nicotine sulfate at the rate of furtheraccentuateleafscorch and1 pint of the 40% concentrate to 100 cause premature dropping of leaves.gallons of water is also effective at Leaf drop interferes with harvesting.temperatures above 70° F. If growers Although it has not been proved ex-prefer dusts, a 5% malathion dust, a perimentally, there are indications that1% parathion dust, or a 4% nicotine feeding of aphids contributes to a re-dust may be used. Aphids are fre- duction in the size and the quality ofquently held in check or heavy in- nuts. festations reduced by the activity of insectpredatorssuchasladybird Life history beetles, syrphid fly larvae, and lace- Aphids appear in early spring whenwings. Malathion and parathion have leaves begin to unfold, and are presentan adverse effect on predators. Nico- throughout the summer. tine is less harmful to beneficial insects.

5 Filbert Bud Mite Phytoptus avellanae

Description and damage Life history Because of the microscopic size of Observations indicate the mite is this pest it is most easily recognizedwelldistributed throughout thenut by the damage it causes. The mite isgrowing areas of Oregon. It is com- almost a transparent white, extremelymonly found on wild hazel. The com- small, and cannot be seen with theplete life history of the mite is not naked eye. Damage is most severe toknown. It has been observed that the theloose budded varietiessuch asmite lives freely upon the leaves dur- Daviana, Royal, Fitzgerald, and Non- ing April, May, and June. As soon as panel. TheThe mite damages female flow-the new growth is produced, they mi- ers as well as leaf buds. Mites also at-grate to and enter the newly formed tack catkins of Barcelona, but havebuds. Mites remain in these buds until not been observed on the catkins of thethe following spring. pollinizers. The catkins become deformed when fed upon but this damage isusually not of economic sig- nificance. Damage caused to the female flower buds is similar to that of the leaf buds. The buds swell into typical big buds and deformed red flowers are produced atthe base ofthegalls. Sometimes the flowers dry up pre- maturely and big buds are not produced. Infested flowers do not produce fruit. Catkins, when attacked by the mite, are distorted, becoming very rigid and brittle, and produce little or no pollen.

Damage to buds by bud mite; undamaged bud on right

Control Satisfactory control measures have not been developed. Partial control has been obtained by the application of lime sulfur at the rate of 10 gallons of lime sulfur to 100 gallons of water applied in the early spring. Applica- tions have been made after pollination has taken place, but before the leaf buds were open. These applications have given approximately 70% reduc- Bud mite damage to catkins tion in the number of distorted buds.

6 Filbert Leafroller Archips rosana

Description Damage Adult moths have a wingspread of The most noticeable injury caused about three-fourths of an inch. Theyby the insect is the rolling of the leaves generally are ofa buff color withby the larvae. The most serious dam- darker irregular linear markings onage, however, is to the young fruit the wings. The first pair of wingsbuds. These are often severely dam- tends to be somewhat rectangular inaged or cut off entirely. Heavy infes- shape. The larvae when mature aretations of leaf rollers can cause a seri- approximately three-fourths of an inchous reduction in the crop. long, light green to darkish-green in color, with a dark head. Life history The insect overwinters in the egg stage. Eggs are laid in silvery masses, having the appearance of overlapping fish scales. Egg masses will be found on limbs and trunks of filbert trees. These masses are somewhat irregular in shape, but usually one-fourth of an inch in diameter. Each mass contains about 50 eggs. The eggs hatch in the spring, usually during the middle to the latter part of April at about the time the young developing leaves are the size of a silver quarter. Larvae feed on the leaves and buds for a period of 3 to 4 weeks, often pro- tecting themselves within the rolled

Filbert Leafroller moth

The filbert leaf roller has been a pest of concern to Oregon filbert growers since1949,althoughanoccasional specimen was observed during the two preceding years. The insect has been reported from British Columbia as a pest of minor importance on various fruits, particularly apple. It has been found in eastern Canada and eastern United States. It also is present in a number of European countries as a pest of tree fruits, small fruits, hops, and ornamentals. Filbert leaf rolled by larva

7 leaves. This is particularly true as thedust to kill the young larvae soon after larvae reach maturity. Larvae pupatethey have hatched from the eggs. Dur- within the rolled leaves and emerge asing the past 8 years, spray notices for moths during the latter part of Junethe control of this pest have varied and July. from April 13 to May 5. The insecticide TDE, also known as DDD, has been the most effective material for the control of the filbert leaf roller. It may be applied as a spray by adding 2 pounds 50% wettable powder to 100 gallons of water or as a 5% dust at a rate of 40 pounds per acre. DDT also has been used successfully at these same rates. It is less effective than the TDE, particularly when the larvae are Filbert Leafroller egg mass protected within the rolled leaves. If DDT is used, application must be made soonaftertheyounglarvaeare Control hatched and before they have an op- The filbert leafroller can be con-portunity to protect themselves within trolled by applications of sprays orthe rolled leaves.

Polyphemus Moth Telea polyphemus

Description and damage The polyphemus moth is the largest moth occurring in Oregon. It is tan in color with an eye spot on each wing 0 and has a wingspread of more than 5 inches. Mature caterpillars are about 3 inches long. They are pale green with pale yellow lines on each side. There are a number of short tubercles on each segment with bright red spots at the base of each tubercle. Polyphemus moth

Life History cherry, hazel, and filbert. Serious dam- The winter is passed in the pupalage to filberts has been observed only stage. The adults emerge in the springon young trees, which are often defoli- and lay large, flat, brown eggs on theated by these caterpillars. leaves of the host plant. The larvae mature in the late summer. There is Control but one generation a year. The cater- Where control is necessary the use pillars feed on a wide variety of hostof lead arsenate as recommended for plantsincludingoak,alder,apple, the filbert moth is suggested.

8 Filbertworm M elisso pus latif erreanus

Description Adult moths have a wingspread of about one-half inch. Gray is usually thedominantcoloralthoughsome moths have a distinct reddish tinge; others appear almost black. The most distinct features are two golden bands across each forewing, one near the middle, the other along the outer edge. When full grown, the larva, or filbertworm, is about one-half inch long and dirty white in color except for the Filbertworm moth brown head. Damage found only in limited numbers in the Soon after it hatches from the egg,major commercial varieties of walnuts the young larva enters the nut. Feed-in this area. ing within the nut destroys the kernel. An occasional infested filbert was The direct damage to the nuts is notfound as early as 1917. In Oregon, the only loss inflicted on the growersfilbert moths were first found doing of filberts by this insect. A greater lossdamage of economic importance to fil- is the cost involved in separating theberts in 1929. In a survey made in wormy nuts from the clean ones in1930 the insect was found throughout processing plants. the filbert growing areas of the state. The exit hole made by the larvaIn 1929 most of the filberts infested when it leaves the nut offers easy ac-were Davianas. By 1937 most of the cess for stored-product pests, such asinfestedfilbertswere found tobe the Indian meal moth and Mediter- Barcelona,the principal commercial ranean flour moth. variety. At the present all varieties appear equally susceptible. Life history Larvae overwinter in silken cocoons. The filbertworm is a native insectThese cocoons may be found in the pest that has adapted itself to filberts. soiland leaves and debris onthe Its native hosts are known to includeground. Most of the worms will be acorns, oak galls made by small wasp- found in the top inch or two of soil. like insects belonging to the familyHowever, in loose soil, they may be Cynipidae, wild hazelnuts, and chinka-found to a depth of several inches. pin. They also are found in sacks in which Larvae have been found in a few in-filberts are handled, and in cracks of stances in overripe, hard cherries andpacking sheds or dryers. Some larvae ripening prunes. This insect is a pestspend the winter in the filberts. A few of Persian (English) walnuts in Cali-pupate within the nuts, but few of fornia. In Oregon it has been foundthese emerge as moths. In the soil in some seedling walnuts, but has beenpupation begins late in May and by the

9 end of June most of the larvae havefeeding is done. The young larva is changed to pupae. Adult moths beginactive, moving about until it finds a to emerge during July. The date thenut. When a nut is located, entrance is first moths appear varieswiththemade between the shell of the nut and season. During an 11-year period, 1947the husk. When a point is reached through1957, thefirst moth emer-where the husk istight against the gence varied from July 3 to July 25.nut shell,it begins to bore into the Moth emergence continues for sev-soft tissue of the husk next to the eral weeks. A few moths do not emergeshell. When the basal scar is reached, until the end of August or the firstthe larva tunnels about until the micro- clays in September. A few larvae de-pyle is located. The micropyle is in the veloping from eggs laid by the earliestcenter of the basal scar and is much emerging moths completetheirde-softer than the rest of the shell. En- velopment, leave the nut, pupate upontrance is made through the micropyle. entering the soil, and emerge as moths the same season, about the time nut harvest begins.This partialsecond brood has not been large enough to cause appreciable damage. The location of the overwintering cocoon has some effect on the time of pupation and the emergence of the Nuts showing entrance through micropyle and adult.Adults emergeearliestfrom exit through micropyle and side those cocoons located in soil, directly exposed to sunlight. Emergence is laterFrequently the larva perishes before from those cocoons in partially shadedentering the nut. Occasionally a larva and those in densely shaded soil.Itfailing to enter one nut will migrate appears that the position of the over-toanother.This occurs mostfre- wintering cocoon is the most impor-quently when two or more nuts are tant factor in accounting for the ex-in a cluster. tended period of emergence. Mating takes place soon after emergence, and egg laying may begin the following day if weather conditions are favorable. Moths are active only on warm, sunny days, and egg laying takes place during the hottest part of the day. Eggs are laid singly on the leaves, usually on the upper surface. An occasional egg may be laid on the Filbertworm damage exposed portion of the nut. The eggs are flattened, milky-white discs about On entering the nut the larva begins one-fifteenth of an inch in diameter.to feed on the kernel. It may tunnel Under ordinary weatherconditionsinto the center of the kernel or exca- they hatch in 8 or 9 days. vate an irregular cavity in the side. The newly hatched larva moves toThe larvae are voracious feeders and the underside of the leaf where somemany are full grown within 15 days

10 after entering the nut. Some of the Spray program larvae leave the nut immediately on Lead arsenate 3 pounds plus reaching maturity.Others,although spreader to 100 gallons water. full grown, remain in the nut until after the harvest. The first spray or dust application When the filbertworm first becameshould be made within a few days after a pest of filberts in Oregon, more thanmoth emergence.Countyextension 90% of the larvae escaped from theagents inform growers when moths nut by enlarging the entrance hole atarefirstobserved.Notallmoths the micropyle. Now that the filbert-emerge at the same time. Of late years, worm has become an established pestmoth emergence has been extended. of filberts, and has stronger mandibles,The extended period of emergence re- the larva is capable of leaving the nutquires that two applications of insecti- at any point. cides be made to insure control. Usu- Parasites usually are not an impor-allythe second applicationis made tant factor in the control of the filbert-about 3 weeks after the first. worm. The egg parasite, Tricho gram- A number of insecticides have been ma evanescens (Westw.), appears totested for the control of the filbert- be the most important natural enemyworm. None has been superior to lead of the filbert moth. During some sea-arsenate. Attempts to kill the larvae sons 15% of the filbert moth eggs arein the soil by treating the soil with in- destroyed by this parasite. secticides have been unsuccessful. In Oregon the principal native hosts Surface application of DDT at the of the filbertworm are acorns and in-rate of two pounds actual DDT per sect galls on oaks. It was probably fromacre have been helpful in cleaning up these sources that the first filberts be-heavily infested orchards. The appli- came infested. This insect is now socation is made when the first moths well established infilbertsthattheemerge. Moths coming in contact with proximity of oaks seems to have littlethe DDT are killed. Lead arsenate is bearing on infestations in the filbertapplied to trees following the DDT orchard. application to the soil surface. Control suggestions Because of their dense foliage fil- Insecticides may be applied in eitherberts are difficult to dust or spray. Care spray or dust form. Many growersshould be exercised to cover all parts prefer to dust for the control of fil-of the tree with the dust, and sprays bertworm. Whatever the method ofshould be applied to the point of run- application, it is important that the joboff. be clone thoroughly. It is particularly Orchard sanitation practices are an important that dust be applied whenaid to the control program. Screening there is no wind. The best time towindows and doors of packing sheds apply dust is at night or in the earlyand dryers adjacent to orchards will morning. prevent moths from escaping. Larvae sometimes leave nuts which are being Dust program transported in bags and overwinter in 40% lead arsenate dust. cocoons spun in the seams. It is desir- Apply the dust at the rate of 40able to store bags in moth-tight rooms pounds per acre. or containers.

11 Omnivorous Leaf Tier Cnephasia longana

Description and damage The omnivorous leaf tier occasionally has been observed doing consider- able damage to the buds and leaves of young filberts. This most frequently occurs in those orchards which have a leguminous cover crop. The young larvae work on the vetch or cover crop and leave it when the cover crop is Omniverous Leaf Tier moth plowed under, attacking filbert leaves: It has been observed to be a serious pest only on the young filberts. In early spring, beginning about the Adult moths have a wingspread offirst of March, these young larvae are about three-fourths of an inch. Thecarriedtosuitable hosts on silken male has an even, grayish-yellow colorthreads by air currents. These minute while the female is grayish, mottledlarvae mine the leaves of low growing with brown spots. The full-grown larvaplants such as clover, vetch, and plan- is about one-half of an inch in lengthtain. On emerging from the leaf mines and grayish-yellow in color. It has twothey migrate to flowers and tender tips light stripes and a darker central stripeof many kinds of plants. on the back. Control Eggs are laid during July on the This insect may be controlled by bark of trees or other rough surfaces.applications of DDT or methoxychlor. The eggs soon hatch into small larvae.Use a 5% dust or 2 pounds of 50% They spin smallsilken cocoonsinwettable powder per 100 gallons of which to overwinter. water.

Scale Insects gon. These are Lecanium corni and Lecanium excrescens. Lecanium corni, known as the brown apricot scale, is the most common and often the most destructive of the Lecanium scales. It attacks a great many kinds of trees and shrubs including filbert and wild hazel. Lecanium excrescens is the larg- Lecanium Scale est scale occurring in Oregon. It is globular in shape and is a third of an Description and damage inch in diameter. It is brown in color Two species of scale insects haveand more or less covered with a white been found attacking filberts in Ore-powdery substance. It is not a native

12 insect and presumably originated inback to the twigs where they spend one of the Asiatic countries. Lecaniumthe winter. excrescens does not appear to be as widespread as Lecanium corni. Control Parasites are important in holding Life history scale insects under control. Occasion- Lecaniurncorniisalmost hemi-ally in some orchards applied control spherical in shape and a shiny brownmeasures are necessary. A 4% dor- color, a little more than one-eighth ofmant oil applied in the dormant season an inch in diameter. The winter isbefore buds open has given effective passed in a half-grown condition. Ma-control of the scale. The crawler stage turity is reached early in May. Eggsof the scale may also be controlled by occur in great numbers during Mayapplications of parathion or malathion and June. They are found beneath theduring July. Parathion at the rate of parent scales. Eggs hatch through July1 pound of 25% wettable powder per and early August, and there is butone100 gallons of water ; or malathion at generationayear. Young crawlersthe rate of 2 pounds of 25% wettable hatching from these eggs move topowder or 1 pint 57% emulsion con- leaves where they feed by suckingcentrate per 100 gallons of water have plant juices. In late summer they movebeen effective.

Filbert Nut Weevil Curculio uniformis

Description and damage Nut weevil has in a few instances been found doing damage to filberts. Serious damage has not been observed in recent years. Adults are about one- fourth of an inch long and brownish- yellow incolor. The beak islong, slender, and curved toward the body. It is longer than the head and thorax combined. The legless larvae are white with brown heads. Filbert Nut Weevil The normal host of this species is acorns. The adult weevil drills holes through the shell of the acorn and de-nuts and enter the soil in early spring. posits one or more eggs in the hole. AsPupation occurs in July. There is but many as five larvae have been observedone generation A year. in a single acorn. Adults are present in July and August. The larvae ma- Control ture about the time the acorns begin Control measures have not been de- to drop. They usually remain in theveloped for this insect and during re- acorns (luring winter. They leave thecent years no control has been needed.

13 Small Gray Leaf Weevil Thricolepis inornata

appears to be various species of oak, but many other hosts including filberts are attacked. Serious damage has only been observed on young trees. The un- folding buds are seriously injured as well as the leaves. Most severe damage has been observed on those filbert plantings which are near oaks.

Control Lead arsenate as recommended for the control of filbert moth has been suggested in the control of this insect.

Damage by small gray leaf weevils

Description and damage This is a small dark gray weevil about three-sixteenths of an inch in length and partially covered with white scales. The normal food of the weevil Small Gray Leaf Weevil

Tree Crickets

Description and damage plants. Often fruits, especially peaches, Two species of tree crickets, Oecan-are badly scarred by tree crickets. thus niveus and Oecanthus nigricornis, have been found on filberts. The adultLife history cricketsareusuallypale yellow or Adult tree crickets imbed their eggs brown in color. Occasionally the adultsin the tender young twigs. On young of Oecanthus nigricornis are almostfilbert orchards this occasionally causes black. The young are nearly white.some damage. A scarred condition of Both the nymphs and adults are pre-filbert nuts somewhat resembling tree daceous, feeding on scales, aphids, andcricket injury topeaches has been other insects. At times, however, theynoticed. The condition has been ob- feed on leaves and flowers of variousserved in varying degrees since 1930.

14 Scarring of the nuts, although it has not caused substantial losses, has been increasing somewhat. The scarred condition of the nuts causes them to be reduced in grade. Control No control measures have been developed. If tree crickets are abundant, parathion or malathion as used for the control of scale insects is suggested.

Damage by tree cricket Tree Cricket

Tingids

Description and damage Corythucha padi was originally de- Two species of tingids (lacebugs),scribed from choke cherry.. It is found namelythewestern willowtingid,commonly on wild hazelnut and on Corythucha salicata,and the chokealder. It has been observed on filberts cherry tingid, Corythucha padi, haveinseveralpartsof the Willamette been found doing damage to filberts.Valley. Adult bugs are easily recog- The former is occasionally a seriousnized by the flat lacelike appearance pestofapplesin western Oregon.of their wings. They usually occur on undersides of leaves and feed by sucking plant juices. Very little of the life history of these insects is known.

Control These insects can be controlled quite satisfactorily by the use of parathion at the rate of 1 pound of 25% wettable powder per 100 gallons of water ; or malathion at the rate of 2 pounds of 25% wettable powder or 1 pint 57% emulsion concentrate in 100 gallons of Tingid water.

15 Eye-Spotted Bud Moth Spilonota ocellana

Description and damage with shiny black heads and about one- The eye-spotted bud moth is an im-half inch long when mature. Occasion- portant orchard pestinthe Unitedally the larvae damage leaves and buds States.It has occasionally been ob-in the spring. served causing damage to young filbert orchards. Adults are somewhat smallerControl than thefilbert moth, grayish-white This pest can be controlled by the with a cream white band across bothuse of parathion or malathion as sug- wings. Larvae arechocolate browngested for control of the filbert aphid.

This bulletin was prepared by B. G. Thompson, professor emeritus of entomology, and R. W. Every, Extension entomologist, Oregon State College. Your County Extension Office can help with local disease and insect control recommendations for filberts and other crops.