Photo 1. Yellow spots of downy mildew, Pseudoperonospora cubensis, on the upper surface of a leaf; they are often angular and restricted by the leaf veins.
Photo 4. Yellow irregular patches caused by downy mildew, Pseudoperonospora cubensis, on the upper surface of a melon leaf.
Photo 5. Downy mildew, Pseudoperonospora cubensis, on the lower surface of a melon leaf showing irregular brown patches where spores are produced.
Photo 3. Underside of a zucchini leaf showing brown patches where downy mildew is forming spores. The white patches are powdery mildew (see Fact Sheet no. 63).
Cucumber downy mildew
AUTHOR Grahame Jackson
Information from Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany; and information (and Photos 1&5) from Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, Tony Cooke, Susan House. CSIRO Publishing. Photos 2&3 Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org. Photo 4 Jacquie (Wright) Kami, formerly Plant Pathologist, Secretariat of the Pacific Community, Suva, Fiji.
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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