Agricultural development in drought-prone Africa conference: In Overseas Development Adrministration: paper 5

Drought prone Africa can be largely equated with the Semi-Arid Tropics of Troll's Classification. It is the home of some 6-700 million people and is characterised by a climate in which there are 2-7 humid months and a rainfall of 500-1,500 mm. (A humid months is one in which rainfall exceeds evapotranspiration). There is an arid season of 5-10 months and this is important in the context of pests and their seasonal carryover. The erratic nature of the rainfall and high arid season temperatures are also important in the context of pests and crop protection since these obviously affect plant growth and hence food and host availability for pests.