As symptoms, initially yellowish, then brownish to dark brown, roundish spots, usually 1 mm in diameter, become visible on both sides of the leaf, which rapidly spread and partially merge. On these spots, the fruiting bodies (pycnidia) of the fungus are formed on the upper and lower sides of the leaves, which are difficult to see with the naked eye due to their small size. On the stems the spots are elongated. Again, you need at least a magnifying glass to clearly see the pycnidia. On the partial fruits, which shrink somewhat when infested, small brown spots with pycnidia can be seen, especially with a magnifying glass.
Prevention and control
- Use of healthy seeds (possibly seed testing).
- Adherence to a crop rotation of at least five years
- Carry out infestation control in the stands and, if necessary, carry out treatment with plant protection products (see list of plant protection products approved in Austria)
Last updated: 09.12.2021