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Lecture 21 Flower and Vegetable PestsLecture 21Flower and Vegetable PestsPests of flowers, roses in particularFlowers have many pests, especially the roses: pests include leaf rollers, aphids, sawflies (rose slugs), gall wasps, weevils,dipterans and others.To paraphrase Johnson and Lyons (Cornell UniversityPress): there are 30 species of cynipid (Cynipidae) gall waspsin the U.S. that belong to the genus Diplolpis.All of them induce galls on Rosa spp., and all plant parts areattacked by one species or another,causing galls on leaves, stems, buds, orroots.The family CynipidaeAlfred C. Kinsey“… Alfred C. Kinsey, professor of zoology at IU from 1920 to his death in 1956. Kinsey was a man of the most taxing intellectual courage. He had established a secure scientific reputation with his study of the gall wasp, which he put at risk when he embarked on a systematic and comprehensive analysis of human sexual behavior--a largely uncharted minefield of gigantic proportions. Contrary to some recent portrayals, Kinsey was not a dogged zealot but--as I experienced him from close range--a marvelously generous man with an unforgettable, radiant smile. He is, in substantive part, responsible for the fairer, kinder and gentler assessment of diverse sexual behavior that is one of the major cultural accomplishments of the second part of the 20th century. Introduction to biography of Kinsey byJames A. JonesThe rose leafhopper: Edwardsiana rosaeFemales insert eggs within the rosecanes in fall. Egg laying producesstems with hundreds of pimple-likedistortions; there may be as many as600 eggs/sq. inch. Eggs hatch in spring and “reddish-eyed”nymphs feed on underside of leaves; complete their development by June and fly to other hosts such as apple trees.Insert their eggs on the underside ofapple trees; eggs hatch in few daysand nymphs severely damage appleleaves. New adults fly back to rosesin fall and proceed to insert eggs intothe rose stems.Eggs onunderside ofapple leavesAug-SeptRosecaneStemcankerdisease mightenter the egg puncturesMayRed-eyednymphsJuneAppleAppleleavesRose leafhopperGenerationdevelops onappleNew adultsfly back to roses& lay eggs.Rose leafhopper --Edwardsiana rosaeLook at the 1926IPM planto control theleafhopper inapple orchards!Rose leafhopperPest description -- Adult insect isgreenish white; immature stages arethe same color, flat, and elongate. Leaves look stippled. Heavy infestationsresult in defoliation.Management --• bifenthrin• carbaryl• diazinon• imidacloprid•lambda-cyhalothrin•permethrinThe Rose Midge: Dasineura rhodophagaMidges are dipterans belonging to the family CecidomyidaemaggotpupariummidgeTorpedo-shapedeggsEggsMaggotShriveled flowersRose gall midge• Overwinter as pupae insilken puparia in the soil• Midges emerge in spring• Lay yellowish, “torpedo-shaped” eggs underflower sepals (A)(B)• Maggots slash tenderbud tissues that die and turn black (C)• Pupate in injured rose tipsand lay another batch ofeggs; may be several gen./yr. (D)• Last summer-generationinstars fall to ground andpupate in soil.EggsswellingDCBARose midge: Dasineura rhodophagaA tiny yellow fly that lays eggs inrose tips. Feeding maggots distortand kill flowers and leaves.Management• Cut out and destroy infested tips• Spray at 10-day intervals with:acephatebifenthrincyfluthrinlambda-cyhalothrinspinosad A&DAnother chrysomelid:western spottedcucumber beetle, Diabroticaduodecimpunctata (Casey)“…in late summer-fall cucumber beetles lay eggs at base of plantsjust beneath the soil. Larvaeemerge in spring and feed on rootsof grasses and herbaceous plants.In summer they pupate in the soil.”“With flowers, the problemis that the adults feed on rosesand other flowers.”Col. Thomas Casey,the great chrysomelidtaxonomist.New Control for Cucumber Beetles!There is a new cucumber beetle bait based on curcubitin, a naturalattractant. The overall bait is composed of curcubaticin™ formulatedwith minute amounts of the insecticide Sevin™ and presented as granules. This bate, called Adios™, is toxic only to cucumber beetles.The Rose Curculio: Family, CurculionidaeThe rose curculio, Merhynchites bicolor, is asmall weevil that’s destructive to both wildand domestic roses. It’s found across thenorthern tier of States and the Southern Canadian Provinces -- it thrives in cool climates.These weevils overwinter as pupae in the soil,emerge as adults in late spring and crawl upto the flower buds. Adults lay eggs in hips andbuds, where small white larvae hatch and feedwithin the flower bud. Buds damaged by larvaewill be deformed and may not even open. Larvaeemerge from buds and drop to the ground topupate. After the egg-laying period in June,adults continue to feed throughout the season.Succeeding generations of the rose curculio canbe managed by removing spent blooms and hips,and by applying Neem oil or Orthene™ during theactive season, in late May-June.Thrips are a huge problem wherevertender plant tissues are found, suchin nurseries and floriculture in general.The rose thrips in particular is a threatto the cultivation of roses in greenhousesor in gardens. The rose thrips belongs tothe damaging genus, Frankliniella spp.Thrips in nurseryAdultEggs1st2nd3rd4thFrankliniella go from eggto adult in 1-2 wks, dependingon temperature regime.Flower thrips cause brown-edged holes and brown spots on flowerpetals. These thrips are carried on frontal wind systems and havebeen found dispersing at 10,000-20,000 ft above sea level. Peak migration is late May-June. Thrips swarm in late afternoon andspread across gardens and fields quickly. They reproduce in warmerclimates all yr. In the PNW they hibernate when it is cool and continuefeeding and development during warm periods.ThripsControl of flower thrips is difficult because of constant migration from weeds, grass, flowers and trees. On roses old blossoms should be destroyed and application of insecticides at closeintervals, especially in late May and June. The following pesticidesgive adequate control of flower thrips on a short-term basis:Insect pests of vegetable gardensTomatoes have many pests: including the spider mites• There are hundreds of mite species;• For a guaranteed nervous breakdown, take a course in Acarology;• As a generality, let’s say, “there are two kinds of mites we worry about,” the spider mites and the blister mites.Blister miteFour spottedspider mite• Spider mites, Tetranychidae,


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UW ESRM 451 - Flower and Vegetable Pests

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