VIEW ARTICLE

Squash Mosaic Virus Variability: Review and Serological Comparisons of Six Biotypes. Merritt R. Nelson, Professor, Department of Plant Pathology, University of Arizona, Tucson 85721; Hjalmar K. Knuhtsen, Assistant in Research, Department of Plant Pathology, University of Arizona, Tucson 85721, Present address: University of Florida, Gainesville 32601. Phytopathology 63:920-926. Accepted for publication 2 February 1973. DOI: 10.1094/Phyto-63-920.

Variants of squash mosaic virus were collected from cucurbit producing areas of the western hemisphere. There were six biotypes in the collection, based on symptomatology and host range. One isolate of each biotype was used to prepare antisera and all were cross-reacted serologically. Only two groups were distinguished on the basis of serological reactions. Group I isolates caused severe symptoms on cantaloupes and most mild symptoms on pumpkins (initially with ringspots). Some members of Group I infected watermelon. No members of Group II infected watermelon, but all produced mild symptoms on cantaloupe and severe effects on pumpkin. With this information it was possible to analyze previous reports of squash mosaic and to assign many of the causal viruses to a serological group.