Pacific Pests, Pathogens and Weeds

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Summary

• 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.