Role of insecticidal seed treatments and refuge for managing soybean aphid virulence

Research Poster
Carlos J. Esquivel
Post Doctoral
Luis Canas
Department of Entomology

Aphid-resistant soybean varieties with Rag (Resistance to Aphis glycines) genes are promising tools for the management of soybean aphid. Intriguingly, there are soybean aphid populations that can overcome such genetic resistance (i.e. virulent aphids) and cause yield losses. Previous research suggests refuge with aphid-susceptible soybean has the potential to control virulent aphid populations, but it is not clear whether it can reverse the proliferation of virulent aphid populations. Seed treatment has shown improvement of soybean aphid control on Rag soybean. To date, however, it is unknown whether refuge strategy and seed treatment combined could improve soybean aphid virulence management. Therefore we evaluated aphid virulence management by planting refuge soybean in a 1:3 aphid-susceptible:Rag-soybean ratio. Seed treatment was applied to either the aphid-susceptible and/or Rag-soybean. All soybean plants were infested with both avirulent (i.e. biotype 1) and virulent (i.e. biotype 4) soybean aphids. Seven days after infestation, we counted the number of aphids of each biotype present. We found that untreated refuge with treated Rag-soybean could provide control over soybean aphid virulence.