Characterization of a Severe Strain of Cucumber Mosaic Cucumovirus Seedborne in Cowpea.

A new seedborne strain of cucumber mosaic cucumovirus (CMV) that induces severe symptoms on many cowpea genotypes was detected in Georgia in 1994. This strain, designated CMV-Csb, is asymptomatic on tobacco, but it produces more severe cowpea stunt symptoms when present in combination with blackeye cowpea mosaic potyvirus than do the more prevalent CMV isolates. The new strain is seedborne in cowpea (1.5 to 37%), has no associated satellite RNA, and is classified as a member of subgroup I of CMV strains based on nucleic acid hybridization assays.