Powdery Mildew General

Powdery mildew (Leveillula taurica)

Credit: Biovision-Infonet

The spots of powdery mildew appear on older leaves and are light chlorotic to bright yellow. These spots later run together and become necrotic. Whole leaf blades may collapse and dry up. On the upper leaf surface of green leaves, a fine talcum-like powder is observed. This is fungal growth.

What to do: Keep tomato fields free of weeds. Do not grow brinjals (eggplant) or tomatoes in succession.

Powdery mildew on Beans (Erysiphe polygoni)

A white powdery mould appears on the upper leaf surfaces. Severely diseased leaves turn yellow and die. Leaf petioles, stems and pods can also be affected.What to do:

• Plough under bean debris after harvest.
• Practise a 2-3 year crop rotation without legumes.
• Avoid continuous bean cropping.