URBANA University of Illinois researchers recently identified a new soybean aphid biotype that can multiply on aphid-resistant soybean varieties. Soybean aphids are the No. 1 insect threat to soybean production in the North Central region of the United States.
Last year, aphid infestation on soybean was high enough that many growers had to spray their fields to control aphids. Despite this, many aphids survived and took flight last fall causing a public nuisance. Migrating soybean aphids have delayed Major League baseball games, closed outdoor cafes and curtailed outdoor activities.
The soybean aphid is the only soybean insect pest known to have multiple biotypes, said Glen Hartman, U of I professor of crop sciences and USDA research plant pathologist. When farmers plant aphid-resistant soybean varieties, they provide protection against Biotype 1. However, recent research indicates that Biotype 2, which was first discovered in 2006, can overcome some aphid-resistant varieties.
The most recently identified soybean aphid, Biotype 3, was discovered in Springfield Fen, Ind., on an overwintering host, glossy buckthorn. Biotype 3 has not been found outside of this location to date and is not distinguishable by its appearance.
Researchers identified Biotype 3 by testing this aphid on soybean plants with known resistance genes. They found it was capable of feeding and multiplying on varieties carrying the resistance genes Rag1 and Rag2.
"Identifying a biotype that can overcome Rag1 and Rag2 resistance, even before soybean varieties with these resistance genes were deployed in production, suggests high variability in virulence within soybean aphid populations," said Curt Hill, U of I principal research specialist. "This gives the pest a high potential to adapt to and reduce the effective life of resistance genes deployed in production."
What does this mean for soybean farmers? A limited number of soybean varieties
|Contact: Jennifer Shike|
University of Illinois at Urbana-Champaign