The genetic relationships among double-stranded RNAs (dsRNAs) from 76 isolates of Discula destructiva obtained from different geographic locations from New York to Alabama were studied by dot-blot hybridization. The dsRNA segments, identified by agarose gel electrophoresis, varied in size and number. Probes were constructed from total dsRNA from six isolates with different dsRNA profiles and of different geographic origins. Each probe hybridized with dsRNA from ca. 62% of the isolates under the high-stringency washing conditions used. No major differences in the percentage of the total isolates that hybridized with each probe were observed. These results suggest a recent common origin of these isolates of D. destructiva.