Detection and distribution of bean pod mottle virus in soybean and bean leaf beetle (Cerotoma trifurcata) vectors in eastern Virginia

Bean pod mottle virus (BPMV) (Comoviridae) is a reemerging disease of soybeans. Vectored by the Bean leaf beetle (Cerotoma trifurcata), this virus has become prevalent on the Eastern Shore of Virginia. Tissue blot immunoassay (TBIA) of soybean sentinel plots for the Legume IPM-PIPE in 2007 detected BPMV at high incidence at the Eastern Shore experiment station, but not at the Tidewater experiment station. Beetles collected in 2008 at the Eastern Shore station were 80% positive for BPMV by TBIA. In a systemic survey in 2009, BPMV was detected in 16 of 42 soybean fields from the southern tip of the Eastern Shore to southern Maryland. Up to 100% of the beetles collected from 24 of 38 Virginia fields were ELISA-positive for BPMV. Infectious virus was recovered from beetle extracts prepared for ELISA and successfully inoculated to soybeans. Fields on the Eastern Shore that were TBIA-positive in 2009 were revisited in 2010. Of the 21 fields surveyed, only 8 were positive for BPMV. An outbreak of BPMV was detected in the Northern Neck of Virginia in 2009, where all 10 fields evaluated were TBIA-positive. Revisiting the Northern Neck fields in 2010 identified BPMV in 3 of 5 fields surveyed. In 2010 an outbreak of BPMV was observed in Appomattox where all 6 fields surveyed were BPMV positive. The primary inoculum of BPMV remains unknown. Sampling of weed species on the Eastern Shore in 2010 revealed some TBIA positive samples, but mechanical transfer to soybeans was unsuccessful.