Worldwide distribution. On tomato, and many others in the same family, including potato, capsicum, eggplant, and some wild hosts in the potato family. An important disease.
Brown spots on the older leaves with yellow margins, and dark brown rings. Leaves dry up and fall. Sunken spots on the fruit.
Wind and rain spread spores; survival in debris and seed.
Cultural control: 2-3-year rotation, avoid planting near old crops; save seed only from disease-free plants; remove 'volunteers', and weeds; check seedlings for disease; space plants (60-90cm); avoid overhead irrigation; ensure good nutrition; collect and burn debris after harvest; check for tolerant varieties.
Chemical control: protectants - copper, mancozeb, or chlorothalonil (protectants); or strobilurins (systemics).