Brown leaf spots (Alternaria porri f.sp. solani Neerg.) on tomatoes

It attacks tomatoes grown both in protected cultivation facilities and in the open field.  Small, rapidly enlarging dark brown spots with a concentric structure are formed on the leaves. The spots formed on the stems, leaf and fruit stalks are larger, also with a concentric structure. They expand rapidly, encompass the entire stem or stalk, and the vegetative part above them dries out. On the fruits, the spots are usually located around the fruit stalk, with a less pronounced concentric pattern. High relative air humidity is a favourable condition for its development.

Control

At the appearance of the first spots, treatment is carried out with Score 250 EC 0.04%, Dithane M-45 0.2%, Curzate M DF 0.25%, Ridomil Gold MZ 68 WG 0.25%, Quadris 25 SC 0.075%.