Risk factors

The disease causes damage mainly in hot, dry climates and its effects are exacerbated in irrigated crops. Early blight develops at temperatures between 20 and 30°C and with alternating dry and humid periods.

High temperatures (20-25°C) on sunny days and dew at night are favourable conditions for the development of the disease.

Early blight is also considered as a sign of weakness in the plant, brought about by nutritional imbalance, drought, plant senescence, insect attacks or mechanical damage.