| molecular, ultrastructural, and biological characterization of pennsylvania isolates of plum pox virus. | plum pox virus (ppv) was identified in pennsylvania in 1999. the outbreak was limited to a four-county region in southern pennsylvania. initial serological and molecular characterization indicated that the isolates in pennsylvania belong to the d strain of ppv. the pennsylvania isolates were characterized by sequence analysis, electron microscopy, host range, and vector transmission to determine how these isolates related to their previously studied european counterparts. genetically, pennsylvan ... | 2011 | 21261466 |