Beginning in July 2005 the Soybean Entomology Laboratory established four suction traps within Iowa. These suction traps have helped entomologists and growers understand the year to year variability in soybean aphid populations

O'Neal, Matthew

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Beginning in July 2005 the Soybean Entomology Laboratory established four suction traps within Iowa. These suction traps have helped entomologists and growers understand the year to year variability in soybean aphid populations.</p

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Iowa State University, Northeast Research and Demonstration Farm                                                                         ISRF05-13Soybean Aphid Aphis glycines Matsumura(Homoptera: Aphididae) Suction Trap MonitoringNetwork in IowaMatthew O’Neal, assistant professorDepartment of EntomologyIntroductionBeginning in July 2005 the SoybeanEntomology Laboratory established four suctiontraps within Iowa. These suction traps havehelped entomologists and growers understandthe year to year variability in soybean aphidpopulations.Materials and MethodsThe suction traps were built to be about 25 ft tall(Figure 1) to collect those winged aphids thatmigrated from buckthorn and soybean, andback. At this height, the traps were unlikely tocollect aphids that might fly from one soybeanplant to another. At the base of the trap was a jarfilled with a preserving fluid. Aphids werepulled down the tube into the jar, and each weekthe jar was replaced. The contents were sent toDr. David Voegtlin at the Illinois NaturalHistory Survey. Dr. Voegtlin is an aphidtaxonomist, and each year he and his assistantssorted through what the traps captured at the endof every week, counting and identifying all theaphids to species. The sex of soybean aphid wasalso identified.Each week’s trap captures were reported at awebsite: www.ncpmc.org/traps/. The site at theNashua farm is just one in a series of nearlytwenty-two traps. At this website viewers cancompare trap captures across the Midwest.Results and DiscussionDuring the first five years of the soybeanaphid’s invasion of North America, Dr. Voegtlinwas reporting a remarkable trend. In years like2003, large populations were reported (several1,000 per plant) during July and August, butvery few if any aphids were caught inSeptember and October. This is interestingbecause aphids making migratory flights duringthe fall are likely flying to buckthorn, theiroverwintering host. Curiously, during years like2004, when very few aphids were observed onsoybean plants during the growing season andfew aphids were collected in suction traps,significantly more were caught during the fall.This trend has been observed several times nowin the suction trap network in Illinois.In the fall of 2005, we observed very fewsoybean aphids collected in the suction traps.However, we did collect a fair amount inSeptember (Figure 2), average (+SEM) persuction trap in September = 25 + 17, with thelargest number collected in Iowa coming fromthe trap at the Nashua farm (118 on September16, 2005). On that date, all of these wereidentified as females. Throughout the 2005trapping season, we did not observe any maleaphids within the suction trap at Nashua.To what extent the suction traps can predictsoybean aphid outbreaks has not yet been tested.We lack any historical data because was the firstyear that the traps ran in Iowa. However, it isinteresting to note that unlike other states(Michigan, Illinois, and Indiana) where few ifany aphids were caught in the fall, there was asignificant number caught in Iowa.We will continue to explore soybean aphidmigration in the coming growing season. Trapswill be run from May to October during 2006.Please visit the website listed above for weeklyupdates.AcknowledgmentsWe thank the Iowa Soybean Association and theNorth Central IPM Center for financial support.Iowa State University, Northeast Research and Demonstration Farm                                                                         ISRF05-1302004006008001000120014001600June July August September OctoberMichiganIndianaMinnesotaIowaIllinoisWisconsinFigure 1. One of four suction traps set up in 2005 forsoybean aphid sampling.Figure 2. Regional summary of suction trap data from 2005 across six states. Traps were deployed forthe first time in all states but Illinois, with all states running traps from mid-July to the end ofOctober. The number of traps varied by state. Visit www.ncipmc.org/traps/ for more information.

Soybean Aphid Aphis glycines Matsumura (Homoptera: Aphididae) Suction Trap Monitoring Network in Iowa

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Soybean Aphid Aphis glycines Matsumura (Homoptera: Aphididae) Suction Trap Monitoring Network in Iowa

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