U.S. scientists have found a new method of fighting a virus that has beleaguered growers of popular cucurbit crops, such as cucumbers and watermelons.

   Many varieties of the widely grown bottlegourd (Lagenaria siceraria) appear to have resistance to Zucchini yellow mosaic virus, or ZYMV, a scourge of commercial cucurbits that includes pumpkins, squashes and other kinds of melons.

   Now two U.S. Department of Agriculture scientists -- plant pathologist Kai-Shu Ling and geneticist Amnon Levi -- have discovered a technique to control watermelon pathogens and pests.

   Ling and Levi, who work at the department's Vegetable Laboratory in Charleston, S.C., obtained seeds for 190 bottlegourd accessions that were collected from different parts of the world. They raised the seeds and inoculated the bottlegourd plants with ZYMV and evaluated how well they resisted the virus.

   They found 36 accessions of the 190 screened -- 33 from India alone -- were completely resistant to ZYMV infection and another 64 accessions were partially resistant. They also found ZYMV resistance is heritable in crosses between different bottlegourd accessions, enabling the development of bottlegourd varieties with enhanced virus resistance.

   The research appeared in the journal HortScience.

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