Anthracnose is a fungal disease caused by Colletotrichum obiculare and affects certain cucurbits, including watermelon, squash, pumpkin, and cantaloupe melon as well as cucumber. Symptoms appear in mid to late season as rounded to irregular brown to black lesions on the leaves and stem often with a yellow halo on the leaves of cucumber. Sometimes sunken lesions 1/4-1/2″ across appear on the fruits accompanied by masses of pink spores. Other fungi and bacteria may enter the spots and destroy the fruit. The disease is especially prevalent in warm, humid, rainy weather and is spread by plant seed, soil, infected plant debris, splashing water, tools, humans, and feeding cucumber beetles. Photo Credit David B. Langston, U GA, Wikipedia
Control
- Use resistant varieties such as ‘Brickyard’ , ‘Diamondback’, and ‘Bristol F1’
- Remove infected plants immediately and dispose of them to reduce the spread of the fungus.
- Wash tools, hands, and clothing that may carry the disease.
- Use a 3 year crop rotation scheme with crops from other plant families
- Water in the morning using drip irrigation or soaker hoses, to reduce splashing and the time that moisture is on the leaves.
- Mulch plants to reduce the effects of rain splashing spores onto plants
- Increase air circulation by increasing space between plants or trimming excess foliage
- In severe cases spray with mancozeb
Karen Meyers