Spots on the leaves - Ascochitosis
A dangerous ascochitosis disease, caused by mushrooms, can affect pumpkins, melons, watermelons, peas, beans, beets, cucumbers, currants, gooseberries, and some other crops.
Ascochitosis - a disease of cultivated plants caused by imperfect fungi, most of which belong to the genus Askohita (Ascochyta).
Description of Ascochitosis
Ascochitosis is manifested by the appearance of convex spots of various shapes and colors (usually brown) with dark bordering. The spots are covered with small brown dots - the so-called pycnidia. They appear on all aerial parts of the plant - stems, leaves, fruits and seeds. On stems, the disease manifests itself in the form of small, punctate or elongated ulcers.
The most characteristic symptoms appear at the base of the stem and at the branches. Affected tissues dry out quickly, which can lead to the death of the plant. Seeds from diseased plants are weak, lightweight, with yellow or brown spots.
Ascochitosis most often affects stems and beans of peas, chickpeas, lentils, and beans. Of particular danger is peas and chickpeas. The spots on the beans are dark brown, convex. Damaged bean leaves do not form seeds.
Prevention of the disease and the fight against ascochitosis
The spread of ascochitosis contributes to humid warm weather. Plants are infected at temperatures above 4 ° C and humidity above 90%. Strong development of ascochitosis is observed with heavy rainfall and at a temperature of 20-25 ° C. With the alternation of wet and dry weather, the development of the disease slows down, and stops at a temperature above 35 degrees.
To prevent damage by fungus, it is necessary to plant only healthy seeds, observe crop rotation (returning of leguminous crops to their former place in 3-4 years), destroy crop residues, and prevent thickening of plantings.
It is important to rake and burn fallen leaves, since the fungus can remain on the plant debris for up to 2 years. A good preventive measure is the placement of legumes in non-affected crops, such as cereals. Autumn autumn plowing is recommended.
Affected parts of plants are recommended to dust with a mixture of copper sulfate and chalk, also crushed coal, spraying the crops during the growing season with fungicides.
With severe damage, diseased plants are recommended to be removed and burned.