A NEW predatory mite has proved to be a boon for Africa's cassava (a root crop) fields. Recently, scientists from the International Institute of Tropical Agriculture (IITA) in lbadan, Nigeria, announced that the battle against the green spider mite, a cassava-destroying pest, had been won two years after a predator mite, Typhlodromalus aripo, was introduced in 12 countries of west and central Africa. T aripo can reduce populations of green spider mites by as much as 90 per cent and avoids the use of pesticides.

The green spider mite, Monony-chellus tanajoa, has been for the past 20 years eating its way through Africa's cassava crop, a staple food for 200 million people. A tanajoa had come to Africa in the 1970s from South America, which is also the original home of cassava. In the absence of a natural predator, the mite had destroyed up to a third of the cassava crops in the continent. After searching for more than a decade, Steve Yaninek of the 1ITA found a solution in T aripo in Brazil. Yaninek is now marketing cassava tips infested with T aripo to countries across Africa.