Powdery mildew

The disease can infect all aerial parts: leaves, flowers and pods. Characteristic of the disease is white greyish powdery fungal growth on affected plant parts. Small chlorotic spots develop on the upper surface of leaves and the corresponding lower surface develops white greyish powdery fungal growth. With time the powdery growth covers the entire lower leaf area. Severe infection causes heavy leaf drop. The fungus develops at temperatures ranging from 20 to 35°C , but 25°C is the optimum. The fungus survives on perennial pigeon peas and volunteer plants, and on the ratoon growth of the harvested plants. Plants with thicker leaves, as most varieties in Kenya are more tolerant to the disease than those with thin succulent leaves (Indian varieties).