Cross-infectivity of Sphaerotheca fuliginea to watermelon, melon, and cucumber

Yigal Cohen, Alexander Baider, Ludmila Petrov, Lanina Sheck, Vladimir Voloisky

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

13 Scopus citations


Powdery mildew has recently become a limiting factor in the commercial production of watermelon (Citrullus lanatus) in Israel. Infection is widespread towards the end of the season regardless of the cultivar. Microscopical examination of conidial shape and germination revealed that Sphaerotheca fuliginea is the causal agent of the disease. Conidia collected from field-grown mildewed watermelon plants produced, upon inoculation in growth chambers, typical powdery mildew symptoms on watermelon, cucumber, Oriental pickling melon, squash, pumpkin, and bottle gourd, but not on melon or sponge gourds. Conidia of S. fuliginea race 1 collected from cucumber and melon were infective only to the hypocotyls of watermelon, whereas conidia of race 2 from cucumber or melon failed to produce the disease on watermelon. It is suggested that S. fuliginea of watermelon is forma specialis citrullus. Among 250 accessions of C. lanatus and C. colocynthis, only two were found to be resistant to this fungus.

Original languageEnglish
Title of host publicationVII Eucarpia Meeting on Cucurbit Genetics and Breeding
PublisherInternational Society for Horticultural Science
Number of pages4
ISBN (Print)9789066058521
StatePublished - 2000

Publication series

NameActa Horticulturae
ISSN (Print)0567-7572


  • Citrullus
  • Cucurbitaceae
  • Powdery mildew
  • Resistance


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