Canadian Forest Service Publications
Characterization of three ascovirus isolates from cotton insects. 2005. Cheng, X.W.; Wang, L.; Carner, G.R.; Arif, B.M. Journal of Invertebrate Pathology 89: 193-202.
Available from: Great Lakes Forestry Centre
Catalog ID: 26433
CFS Availability: PDF (request by e-mail)
Three new ascovirus isolates were discovered from lepidopteran larvae in cotton fields in Blackville, South Carolina, USA, and were named TnAV-2c, TnAV-2d, and HvAV-3f. TnAV-2c and TnAV-2d were compared by restriction endonuclease (REN) profiles and found to be similar. HvAV-3f was isolated from Helicoverpa zea, and bears remarkable dissimilarity in REN profiles to the reported SeAV-5a from Spodoptera exigua but DNA hybridization shows they are closely related. Major capsid protein (MCP) and ? DNA polymerase from the three isolates were sequenced, which suggests the three isolates are novel. Phylogenetic analyses showed that TnAV-2c is distantly related to other lepidopteran ascoviruses. HvAV-3f and SeAV-5a may also be variants of the same species based on Southern, Western, and MCP/DNA polymerase gene sequence analyses. High levels of TnAV-2 infection in an H. zea population (as high as 74%) were recorded in a cotton field in Blackville, SC. Observations in this field showed that infection by ascovirus altered the feeding behavior of H. zea larvae.
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