Which aphids are important vectors of soybean mosaic virus?

Soybean mosaic virus (SMV) is an aphid-vectored plant virus that infects soybean and can reduce yield by 8 to 35%. This virus is vectored non-persistently by the invasive pest Aphis glycines. Before the arrival of A. glycines, transmission of the SMV was dependent on several species of non-colonizing aphids. To determine what aphids are important vectors of SMV we compared data sets for the abundances of alate A. glycines and non-colonizing aphids to the monthly prevalence of SMV. Alate abundance data and SMV prevalence were collected during June, July, August, and September for the 2005, 2006, and 2007 field seasons. Alate abundance was measured in four suction traps stationed in northwest, northeast, central and south-central Iowa. During this period several aphid-vectors of SMV were collected, including A. glycines as well as 14 non-colonizing aphid species. Prevalence of SMV was estimated by a survey of commercial fields conducted in each of the 99 counties of Iowa. The greatest prevalence of SMV occurred during years in which A. glycines outbreaks were common in Iowa (i.e. 2005 and 2007). Combining alates of all non-colonizing aphids that vector SMV explained 91% in 2005, 67% in 2006, and 54% in 2007 of SMV prevalence. Alate A. glycines explained 99% in 2005, 30% in 2006, and 55% in 2007 of SMV prevalence. Results suggest that SMV variation is not explained better by the abundance of alate A. glycines when compared to non-colonizing aphids.