In this disease, Alternaria fungus attacks leaves, stems, fruits and seeds. Infection in tomato seeds may cause seedling death. On the leaves and leaflets, the signs appear as brown spots, which often have chlorotic edges. On the surface of the spots, concentric wavy circles may appear. The spots develop quickly and may even burn all the aerial parts. The symptoms of the disease are similar on the stems and leaves of tomatoes and potatoes, and the appearance of spots on the stems of potatoes and tomatoes is the same as leaf spots. It often appears on old leaves.
Symptoms:
In tomato fruit, the symptoms of the disease appear in the form of blackish-brown spots at the junction of the fruit with the fruit tail. The surface of the spots may be covered with a black coating of the fungus and become wavy.
In the potato tuber, black spots appear with a definite margin and with a few centimeters of depression in the tuber tissue. The texture under the spots is brown sponge. The diameter of the spots sometimes reaches two centimeters.
It is caused by a fungal disease (Alternaria solani).
Disease control:
1. Planting healthy or disinfected seeds.
2- Observing two or three year rotations and collecting infected plant debris and eliminating them is effective in controlling the disease.
2- Observing two or three year rotations and collecting infected plant debris and eliminating them is effective in controlling the disease.
