Foliar-feeding insectsESRM 451Bob GaraFoliar Pests of Homes and GardensBob GaraESRM451Spruce AphidThe spruce aphid“Early season control is key to successful treatment. Usually by the time damage is noted, it’s too late for effective control”First, an up front message!A, Winged adult; B, Wingless adult & C, NymphsSpruce aphid, Elatobium abietinumToo, too late!A major foliar pest of rhododendrons: asJohnson and Lyons (Cornell UniversityPress) say, “…the most injurious pest ofthem all, especially on rhododendrons.”The doiliesReally, the Lace BugsTingidaeThe tingid on rhododendrons isStephanitis rhododendri• The rhododendron lace bug sucks the sap on theunderside of leaves. • As feeding progresses, a light stippling occurs on the upper leaf surface. After a while the surface will be bronzed. • The lace bug may be found (sign) on the underside of the leaf as well as blackish fecal material that’s stuck to the leaf.Why, yesthose are lace bugeggs.Winter, pinkisheggs along veinsEggs hatch in springAdults in AugustMate in fall and lay eggsTreat the nymphsLife historyof the lace bugControl aimedControl aimedat the nymphsat the nymphsas they hatchas they hatchfrom eggs in from eggs in spring.spring.The elm leaf beetle,Pyrrhalta luteolaFam.: ChrysomelidaeLet’s diverge a bit and talkabout the Chrysomelidae, theleaf beetles.A note on the leaf beetles, Chrysomelidae One way to create pests is by changing the environment Another way is by introducing them to the U.S. from othercountries -- all too common! Another way is to export pests to other countries & wehave done this with chrysomelids like the Colorado potato beetleThe Colorado potato beetle (Leptinotarsa decemlineata) fed onbuffalo burr, a plant native to the Great Plains. When the settlersplowed up these vast areas and planted potatoes, the Coloradopotato beetle switched its host preference to the other, now-more-common Solanaceae, the potato! A case of “Changing the Environment.”Perhaps just as bad, the Colorado potato beetle has been exportedall over the world were potatoes are grown.The chrysomelids, leaf beetles, are one of the largest beetle families as well as one of the most damaging to agriculture. For example, the U.S. is responsible for one of world’s most important pests, the Colorado potato beetle, Leptinotarsa decemlineata.Even in Spain!El escarabajo del Colorado:These are all chrysomelid beetles.They have all been described by Col. Thomas L. Casey, U.S. Army.Col. Thomas L. Casey: the great collector of thebeetle family, ChrysomelidaeDid you see that chrysomelid crawlingup the wall?Col. Thomas L. CaseyOfficers andwives at FortCasey, WhidbeyIsland, WACaseyEnough of that, “let’s hear about leaf-feedinginsects!The elm leaf beetle was introducedfrom Europe. It is extremely damaging to elms in Germany andFrance. It appeared in Baltimorein 1928 and spread across the U.S.quickly; found in Portland, Oregonin 1938.(1) Adults overwinter in secluded places; (2) emerge in spring just as elms areunfurling their new foliage; (3) the sexually immature females feed on these leaves, leaving small holes in the foliage;(4) in May-June eachfemale lays ±600 eggs in clusterson leaves, branches and trunk;(5) larvae skeletonize the foliage; in a heavy infestations that last 2+ yrsmany trees weaken and die; (6) late summer the last instars fall to the ground and pupate and;(7) new adultsfly to secluded places.last instars faEggs hatchEggs hatchA calculation knownas degree-days is usedto approximate wheninsects emerge in thespring. In particular,the calculation asks, whenare the immatures feeding?The most susceptible insectstages to insecticides arethe early instars, e.g. 1stand2ndinstars.Degree-daysMaxMin thermometerThe WSU Pest Control Handbook suggests several pesticides that could be used to control a developing outbreak of the elm leaf beetle. These treatments are aimed at the early instars. At the UW campus a degree-day chart is used to predict when trees should be sprayed.250 accumulated degree-daysis used as the “action threshold”Accumulated degree days1998 1999 2000 etc.(use degree-day graph)Tropical chrysomelidbeetleWestern tent caterpillarForesttent caterpillarEasternTent CaterpillarsEggsPupaLarvaThe Forest Tent Caterpillar, M. disstriaEggsAdultsPupaLarvaLife cycle ofM. californicumWell all of this is extremelyinteresting. Right?The western tent caterpillar: Malacosoma californicumWellington, W.B. 1957. Individualdifferences as a factor inpopulation dynamics: the developmentof a problem. Can. J. Zool. 35:293-323.A briefdescriptionof Wellington’sexperiments.More experiments ofshining a light at oneend of a table-top runwayPotted red aldersSome food forthought!Type I and Type IItentsControl: Pick them off, destroy tents, or spraywith Bt if necessary. Time sprays to controlearly instars; the tents still aren’t sturdily madeand the Bt will get to the larvae. The Bt will alsobe infested as larvae feed.Thrips damage:(a). western flower thrips (Frankliniella occidentalis) -- flowers, grapes, raspberries, and vegetables(b). onion thrips (Thrips tabaci) -- ononions, nursery plants, and vegetablesJune - AugustDamage of the privetthrips, DendrothripsornatusAll spring through summerLate summerWinterLate WinterApply when insects appear on foliage:¾ spinosad¾ carbaryl ¾ Beauvaria bassiana¾ bifenthrinThripsThe Hymenoptera SymphytaApocritaSawflies - Hymenoptera• One pair of simple eyes• Five or more prolegs• Prolegs without crotchetsCaterpillars - Lepidoptera• Six ocelli grouped in the formof a letter “C”• Five or less prolegs• Prolegs have crotchetsThe larvae of sawflies are distinct from caterpillarsThere are somereally cutecaterpillars outthere.(A)(B)Typical adultsawfly of the genusDiprion (A) and larva(B).Sawfly ovipositorSawflies have a saw-like ovipositor for sawingslits in foliage and inserting their eggs in theseslitsThe pear slug,Caliroa cerasiSpinosadThe leafrollersThe leafcrumblersThe leafwrappersThesecharacteristics:• Adult shape• Eggs• Larval behavior• Larval mouthis prognathusPrognathusmouthpartsHypognathusmouthpartsTortricidaeExamplesof tortricidsTypical tortricidwe have in thePNW: cotoneasterwebworm.Cotoneaster webwormTortricid in tropicalLatin AmericaOne more time!The aphids:• rhododendrons• alders• maples• everythingAn aphid diet – all in vein.Generalized life cycle of aphidsIt’s in