The causative agent of Mealy dew develops on leaves and stalks of a cucumber, a vegetable marrow, a pumpkin, a bush pumpkin since growth of plants. Mealy dew does the greatest harm at the raised humidity of air and sharp differences of temperatures. At defeat of plants on leaves (at first on the top party, and then and on bottom), there are mealy white stains - an infecting agent mycelium. Leaves turn yellow and dry up. Fruits on affected plants late set, often remain underdeveloped.
The infecting agent winters on the rests of sick plants, and also on other plants affected with mealy dew.
Struggle measures:
- Removal of tops of pumpkin and weed plants,
- Deep dig over soils in the autumn,
- Return of pumpkin cultures on a former place after three-five years only,
- Maintenance of normal humidity of soil,
- At occurrence of first signs of mealy dew spraying of plants by colloidal sulphur (20 g on 10 l of water in an open ground and 40 g on 10 l of water - in the protected ground).
