Scientists have successfully used tiny wasps and an invisible fungus disease to battle pests destroying cassava crops in Africa and South America. Cassava, a starchy root crop native to Latin America, was taken across the Atlantic by Portuguese traders four centuries ago and is now a major food for more than 200 million Africans. But transported along with the crop was the mealy bug, a pest that has caused extensive damage to cassava plantations.

Scientists at the International Centre for Tropical Agriculture (CIAT) in Cali, Colombia, have found wasps that parasitise the bug. These were shipped to Africa and released. Additional natural enemies of the bug discovered in South America by CIAT were also brought to Africa.