ARS | Publication request: Field and laboratory evaluations of soybean lines against the soybean aphid (Hemiptera: Aphididae)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2011
Publication Date: April 1, 2012
Citation: Hesler, L.S., Prischmann, D.A., Dashiell, K.E. 2012. Field and laboratory evaluations of soybean lines against the soybean aphid (Hemiptera: Aphididae). Journal of Economic Entomology. 105:608-615.

Interpretive Summary: The soybean aphid is a major pest that significantly reduces soybean yield in northern production areas of North America. Insecticides are widely used to control soybean aphid outbreaks, but effective alternative management strategies such as host-plant resistance are needed to alleviate insecticide use. Laboratory screening is necessary to identify resistant lines, and field evaluation is required to validate resistance and possible strategies for deploying it against soybean aphid. Both field and laboratory tests were conducted in this study, and some lines previously reported with resistance to soybean aphid failed to show consistent patterns of resistance. For instance, relatively high aphid counts on Tie-feng 8 in two years of field testing contrasted with previously reported resistance in screening tests. Intermediate levels of soybean aphid occurred in field plots on lines previously shown with strong (Sugao Zairai, PI 230977, D75-10169) or moderate resistance to soybean aphid (G93-9223, Bragg, Braxton, Tracy-M). Bhart-PI 165989 showed resistance in one of two laboratory tests, but had relatively large aphid infestations in both years of field tests. Sugao Zairai also failed to show significant resistance in two laboratory tests against aphids field-collected in 2008, but it was resistant in laboratory tests with aphids collected in 2002, 2005 and 2006. Six soybean lines previously identified with resistance to soybean aphid—Jackson, Dowling, K1639, Cobb, Palmetto and Sennari—were resistant in our tests. Overall, results showed that lines with the Rag (i.e., Jackson) or Rag1 gene (i.e., Dowling) had low aphid numbers, whereas lines with Rag2 (i.e. Sugao Zairai, Sennari) had mixed results. Collectively, responses of soybean aphid populations in laboratory and field tests in 2008 matched a virulence pattern reported previously for biotype 3 soybean aphids. These results, coupled with previous reports of biotypes virulent to Rag1, suggest that deployment of lines with a single aphid-resistance gene is limited for soybean aphid management, and that deployment strategies relying on multiple resistance genes may be needed to effectively use plant resistance against soybean aphid.

Technical Abstract: The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean that significantly reduces yield in northern production areas of North America. Insecticides are widely used to control soybean aphid outbreaks, but efforts are underway to develop host-plant resistance as an effective alternative management strategy. In this study, previously identified resistant lines were evaluated in laboratory tests against field-collected populations of soybean aphid and in field-plot tests over two years in South Dakota. Six lines previously identified with resistance to soybean aphid—Jackson, Dowling, K1639, Cobb, Palmetto and Sennari—were resistant in this study, but relatively high aphid counts on Tie-feng 8 in field plots contrasted with its previously reported resistance. Bhart-PI 165989 showed resistance in one of two laboratory tests, but had relatively large aphid infestations in both years of field tests. Intermediate levels of soybean aphid occurred in field plots on lines previously shown to have strong (Sugao Zairai, PI 230977, D75-10169) or moderate resistance to soybean aphid (G93-9223, Bragg, Braxton, Tracy-M). Sugao Zairai also failed to have a significant proportion of resistant plants in two laboratory tests against aphids field-collected in 2008, but was resistant in laboratory tests with aphids collected in 2002, 2005 and 2006. Overall, results showed that lines with Rag (i.e., Jackson) or Rag1 gene (i.e., Dowling) had low aphid numbers, whereas lines with Rag2 (i.e. Sugao Zairai, Sennari) had mixed results. Collectively, responses of soybean aphid populations in laboratory and field tests in 2008 matched a virulence pattern reported previously for biotype 3 soybean aphids. These results, coupled with previous reports of biotypes virulent to Rag1, suggest that deployment of lines with a single aphid-resistance gene is limited for soybean aphid management, and that deployment strategies relying on multiple resistance genes may be needed to effectively use plant resistance against soybean aphid.