AVRDC International Cooperators'
Colletotrichum lagenarium (Glomerella cingulata var. orbiculare)
The disease is particularly damaging to watermelon,
cucumber, and cantaloupe, but also may occur on most other
cucurbit crops. On cucumber and cantaloupe, leaf lesions are
circular and brown up to 1 cm in diameter, while on
watermelon the leaf lesions are black and somewhat smaller.
Petiole and stem lesions are elliptical in shape and sunken.
Fruit lesions appear at or near maturity as watersoaked spots
that develop into sunken, circular lesions lined with dark fungal
stroma bearing masses of pink spores.
Symptoms on melon
Conditions for Development
Disease is favored by extended periods of rain and warm temperatures. The pathogen
persists in crop debris, is seedborne, and may survive on volunteer crop plants or
cucurbit weeds. In the field, watersplash and windblown rain disperse the fungus.
Use resistant cultivars when available. Fungicidal sprays generally are necessary when
susceptible cultivars are grown under conditions conducive for disease development.
Last updated: 2001.
Information from: Vegetable Diseases: A Practical Guide. Lowell L. Black, AVRDC.
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