Vascular wilt wither the cotyledons and the first present leaves of a water-melon and a melon, keeping green coloring, become thin a root neck, on root hairs there are brown stains.
The harm put Vascular wilt, in a greater degree depends on terms of its occurrence, a cultivated grade and other factors. Most strongly Vascular wilt defeats middle - and late-ripening plants.
At defeat of plants, except productivity decrease, sugar content, fragrance, juiciness and storage characteristic of fruits decrease. Vascular wilt is shown during the period from shoots before formation of the second-third present sheet, during time of ripening and maturing of fruits.
Leaves wither and adult plants, also without losing green colouring. Usually lashes of one plant, as a rule, wither simultaneously. Plants depending on a place and defeat degree perish within two-eight days after occurrence of external signs of disease. At withering of plants of a melon are marked lighter a sheet plate (chlorotic), change of its shade to grayish-silvery and spottiness of leaves.
Infecting agent is the fungus fusarium oxiporum. Infection of plants occurs through root system. Because the infection collects in soil, it is not necessary to cultivate cucurbitaceous agricultures on the same field within several years. It is not recommended to place cucurbitaceous agricultures also after a potato, a tomato and an eggplant.
Fusarium intensively grows at temperature 25 - 30°C . Its growth is slowed down at temperature above 35°C , stops at 5°C . Optimum for growth of this fungus humidity of the soil equal 50 - 80% of a full field moisture capacity. The fungus can grow and develop on the salted soils.
At excessive watering, flooding of plants, their cultivation on heavy soils with close bedded ground waters fructifying plants of a melon wither in the end of July - August.
Measures of struggle against Vascular wilt:
- Returning cucurbitaceous agricultures on a former place not earlier than in six-seven years;
- Cleaning and burning of the rests of defeated plants;
- Deep under-winter ploughing;
- Treatment of seeds with solution 40%-s' formalin within 5min and two-hour soaking;
- Crops of seeds of a water-melon on easy sandy soils and melons - on easy loamy soils with deep occurrence of ground waters;
- Crops of seeds on high ridges on which root necks of plants are above a line drench of soils;
- Steady, short watering, without excessive humidifying of soil, loosening of an irrigation furrow after each watering;
- Spraying of plants during the period of budding - the beginnings of formation of fruits with 5%-s' extract from superphosphate or a solution of chloride potassium.
