Population growth of soybean aphid, Aphis glycines, under varying levels of predator exclusion
1Department of Entomology, 1-31 Agriculture Bldg., University of Missouri, Columbia, MO 65211
2Monsanto Company, 700 Chesterfield Pkwy W., Chesterfield MO, 63017
3108 Waters Hall, University of Missouri, Columbia, MO 65211
4Agricultural Experiment Station Statistician, 307E Middlebush Hall, University of Missouri, Columbia, MO 65211
Abstract
Although soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has caused economic damage in several Midwestern states, growers in Missouri have experienced relatively minor damage. To evaluate whether existing predatory insect populations are capable of suppressing or preventing soybean aphid population growth or establishment in Missouri, a predator exclusion study was conducted to gauge the efficacy of predator populations. Three levels of predator exclusion were used; one that excluded all insects (small mesh), one that excluded insects larger than thrips (medium mesh), and one that excluded insects larger than Orius insidiosus (Say) (Hemiptera: Anthocoridae), a principal predator (large mesh). Along with manipulating predator exposure, timing of aphid arrival (infestation) was manipulated. Three infestation times were studied; vegetative (V5), beginning bloom (R1), and beginning pod set (R3). Timing of aphid and predator arrival in a soybean field may affect the soybean aphid’s ability to establish and begin reproducing. Cages infested at V5 and with complete predator exclusion reached economic threshold within two weeks, while cages with predators reached economic threshold in four and a half weeks. Cages infested at R1 with complete predator exclusion reached economic threshold within five weeks; cages with predators reached economic threshold within six weeks. Cages infested at R3 never reached threshold (with or without predators). The predator population in Missouri seems robust, capable of depressing the growth of soybean aphid populations once established, and even preventing establishment when the aphid arrived late in the field.
Keywords: Predator complex, Predator exclusion, Orius insidiosus
Abbreviations: R1, beginning bloom; R3, beginning pod set; V, vegetative; WAI, weeks after infestation
Correspondence:
a*lnm2m9@mizzou.edu,
bThomas.L.Clark@monsanto.com,
cBaileyW@missouri.edu,
dEllersieckM@missouri.edu, *Corresponding author
Associate Editor: J.P. Meihls was editor of this paper.
Received: 3 April 2009 | Accepted: 16 September 2009 | Published: 10 September 2010
Copyright: This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.
ISSN: 1536-2442 | Volume 10, Number 144
Meihls LN, Clark TL, Bailey WC, Ellersieck MR. 2010. Population growth of soybean aphid, Aphis glycines, under varying levels of predator exclusion. Journal of Insect Science 10:144, available online: insectscience.org/10.144
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