Tomato fruit with dark, circular, sunken spots are showing symptoms of anthracnose, caused by several species of the fungus Colletotrichum. Early symptoms appear on a ripened fruit as small, slightly sunken, water-soaked, circular spots. The lesions increase in size, become more depressed, and the central portion darkens. The darkened area contains many small, dark, fungal structures from which masses of salmon-colored spores (reproductive structures) are released in moist weather. As the fungus spreads within the fruit, a semisoft decay occurs. The fungus can infect both green and red fruit, and it can penetrate the skin of uninjured fruit. When green fruit are infected, it does not show spotting until it begins to ripen. Tomato fruit become increasingly susceptible as they approach maturity. Warm, wet weather promotes disease development. Splashing water in the form of rain or overhead irrigation favors the spread of the disease. Remove and destroy infected fruit. Rotate plantings in your vegetable garden. Weed control is important because the pathogen (fungus) has a broad host range that includes many common weeds. Regular fungicide applications can help prevent infections. Fungicide applications should begin when fruit are formed on the first cluster. Contact your local Extension office for fungicide recommendations.

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