Abstract
Double-stranded (ds) RNAs associated with viruslike particles have been found in six isolates of Alternaria alternata which produce tentoxin. Isolates had from one to three dsRNAs ranging in size from 1.0 to 5.1 kilobase pairs. In two isolates the dsRNAs were associated with 30-nm particles. No dsRNA was detected in any of six other tentoxin-producing isolates or nine isolates which did not produce tentoxin.