Gray mold or botrytis in roses.
The causative agent of gray mold is a fungus Botrytis cinerea Pers, which affects about 200 different species of plants. We rose from botrytis affected mainly buds with pedicels, the ends of young stems and leaves; in wet weather, they are covered with gray fluffy coating.
First of all this rot attacks the weakened roses, and most of all - with white and pale pink flowers. Buds on the affected botrytis roses were not disclosed, rot and fall off. On the petals appear small brown spots (sores), the leaves turn yellow and fall off, too. Botrytis affected young roots and cuttings.
Foci of infection persist in plant debris as mycelium (mycelium), which produces spores in the spring. Then spread the spores of the fungus insects and the wind. Therefore undesirable "neighbor" for the roses is, for example, strawberry, frequently ill botrytis.
Gray mold appears on roses with thickened crop or if glaze rosary made late in the evening, when the leaves do not have time to dry roses till night. Measures to combat and prevent botrytis in roses are the same as against other fungal diseases.