Pacific Pests & Pathogens - Mini Fact Sheet EditionCucurbit leaf spot (145)
Pacific Pests & Pathogens - Mini Fact Sheet EditionCucurbit leaf spot (145)
Summary
- Worldwide distribution. On watermelon (and squash), and other members of the cucumber family, including weeds. A minor disease, worse under shade.
- Small, about 5 mm, round spots with grey centres, brown margins, and sometimes yellow halos. Centres may fall out, spots merge, resulting in black areas, and leaf fall.
- Spores on the underside of the leaves are spread in wind and rain.
- Cultural control: do not plant new crops next to old; use 3-4-year rotation; weed; do not grow watermelon under shade; collect and burn trash after harvest. Chemical control: copper, chlorothalonil, or mancozeb.
Common Name
Cercospora leaf spot
Scientific Name
Cercospora citrullina
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 from Schwartz, Gent DF (2007) Cercospora leaf spot (cucumber, melon, pumpkin, squash, and zucchini). High Plains IPM Guide, a cooperative effort of the University of Wyoming, University of Nebraska, Colorado State University and Montana State University. (http://wiki.bugwood.org/uploads/CercosporaLeafSpot-Cucurbits.pdf). Photos 1&2 Gerald Holmes, Valent USA Corporation, Bugwood.org.
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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