Avoid excessive watering. For control and treatment, spray with benomyl, captafol or vinclozolin. To get effective control, the spray must cover both upper and lower surfaces of leaves. Destroy infected plant parts. They thus reduce photosynthesis, creating a moist microenvironment on the foliage which encourages proliferation of other aerial diseases.
Control insects with insecticides such as diazinon or dimethoate.
Use fungicides like mancozeb, thiram or benomyl to control fungus. Flower turns grey or black prematurely. The causal agent is thrips in the the flower buds. Control thrips with insecticides like methamidophos, dimethoate, methiocarb. Spray fungicides like benomyl or captan to control fusarium.