- Widespread distribution. In tropics and sub-tropics. A wet-weather disease, common on cucurbits, i.e., members of the cucumber family, especially, cucumber, melon and watermelon. An important disease.
- Angular dark brown spots on watermelon; brown spots on melon and cucumber with halos, and centres that fall out. Large, brown, round, sunken spots on the fruit, with pink spore masses in wet weather.
- Spread in wind-blown rain; longer distances in seed.
- Cultural control: certified seed; tolerant varieties (cucumber, watermelon); check seedlings in nursery; avoid planting near older infected crops; avoid overhead irrigation, or apply early in the day; avoid entering fields when plants are wet; weed; collect and burn trash after harvests; crop rotation.
- Chemical control: copper, chlorothalonil, or mancozeb.
Pacific Pests, Pathogens, Weeds & Pesticides
Cucurbit anthracnose (200)
Photo 1. Angular brown spots on the leaf of watermelon, caused by the anthracnose fungus, Colletotrichum orbiculare.
Photo 2. Round and oval light brown spots showing 'shot-hole' symptom on cucumber, caused by the anthracnose fungus, Colletotrichum orbiculare.
Colletotrichum orbiculare; sometime known as Colletotrichum lagenarium. Three races are known.
AUTHORS Grahame Jackson & Manu Mua
Information from Harris M (2014) Colletotrichum orbiculare (anthracnose of cucurbits). BugwoodWiki. (https://wiki.bugwood.org/Colletotrichum_orbiculare_(anthracnose_of_cucurbits); and Cucurbits, Anthracnose (undated) The Center for Agriculture, Food, and the Environment. University of Massachusetts Amherst. (https://ag.umass.edu/vegetable/fact-sheets/cucurbits-anthracnose); and from CABI (2019) Colletotrichum orbiculare (anthracnose of cucurbits). Crop Protection Compendium. (https://www.cabi.org/cpc/datasheet/14917). Photos 1 Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org. Photo 2 Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org. Photo 3 Kohler F, et al. (1997) Diseases of cultivated crops in Pacific Island countries. South Pacific Commission. Pirie Printers Pty Limited, Canberra, Australia. Photo 4 Charles Averre, North Carolina State University, 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.