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ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Publications at this Location » Publication #356240
Title: Weekly survivorship curves of soybean aphid biotypes 1 and 4 on insecticidal seed treated soybean

Author
item ESQUIVEL PALMA, CARLOS - The Ohio State University
item Ranger, Christopher
item PHELAN, LARRY - The Ohio State University
item MARTINEZ, ERICK - University Of Missouri
item HENDRIX, WILLIAM - Valent Usa Corporation
item CANAS, LUIS - The Ohio State University
item MICHEL, ANDY - The Ohio State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary: Thiamethoxam, a commonly used insecticide used in soybean seed treatments, suppresses soybean aphids for only a short time after planting. However, exactly when and how quickly soybean aphid population increase after planting is unknown. Likewise, we lack data on the performance and fitness of virulent soybean aphid biotypes when fed on seed treated soybean. Determining the survival of soybean aphids over time on seed treated soybean is critical for improving soybean aphid management and may provide insights concerning managing virulence to soybean aphid-resistant soybean. In greenhouse and field, aphid-susceptible soybean plants with and without seed treatment were infested with aphids at varying lengths of time after planting. Aphid survival was then examined. Plant tissues were also analyzed to measure thiamethoxam concentrations. Soybean aphid survival was lower on seed treated soybean up to 35 days after planting. Plant tissues analyses determined thiamethoxam levels also began to decrease 35 days after planting. Our study characterized the relatively short duration of seed treatment effectiveness on soybean aphid.

Technical Abstract: Thiamethoxam, a commonly used insecticide used in soybean seed treatments, effectively suppresses soybean aphids (Aphis glycines Matsumura) for only a short time after planting. However, exactly when and how quickly soybean aphid population could increase is unknown. Likewise, we lack data on the performance and fitness of virulent soybean aphid biotypes when fed on seed treated soybean. Determining the survival of soybean aphids over time on seed treated soybean is critical for improving soybean aphid management and may provide insights concerning managing virulence to soybean aphid-resistant soybean. In greenhouse and field, aphid-susceptible soybean plants (with and without seed treatment) were infested at 7, 14, 21, 28, 35, and 42 days after planting (DAP). We compared aphid survival among biotypes (i.e. biotypes 1 and 4) and insecticide treatment 72 h after infestation. We also collected plant tissues to measure thiamethoxam concentrations using liquid chromatography-tandem mass spectrometry. As expected, soybean aphid survival was significantly lower on seed treated soybean up to 35 DAP for both biotypes, which correlates with the decrease of thiamethoxam in plant over time. Moreover, we found no significant difference between biotype survivorship on seed treated soybean plants, although we did find significantly greater survival for the virulent biotype compared to the avirulent biotype on untreated soybean in the field experiment. In conclusion, our study further characterized the relatively short duration of seed treatment effectiveness on soybean aphid, and reports that survivorship of virulent aphids on seed-treated soybean is similar to avirulent aphids.