Abstract

Cassava and sweet potatoes, important food staples for many of the poorest countries in eastern and southern Africa, are severely affected by a number of pests. The Commonwealth Institute of Biological Control, together with the Africa-wide Biological Control Program of the International Institute of Tropical Agriculture (IITA), have successfully introduced a parasitic wasp which has reduced the damage caused by the cassava mealybug, the most destructive pest. This project seeks to continue the introduction and testing of this and other parasites and predators in areas affected by the mealybug and other pests, and to assist national research programs throughout the region to develop a capacity for integrated pest management research so that they can combat future pest outbreaks.

Post-Project Summary

A standardized data collection method was developed and field-tested in both Kenya and Malawi. Rapid multiplication of high-yielding and disease-resistant sweet potatoes was carried out, and plant material distributed to farmers. Research on the development of an integrated pest management package for the control of the major sweet potato pest in East Africa, the sweet potato weevil (Cylas spp.) was carried out in Kenya. This component included life cycle and behavioral studies, pheromone extraction, bioassays application, study of cultural control methods, and isolation and laboratory testing of fungal pathogens as biological insecticides. Sweet potato pests infected with entomopathogenic fungi were collected, and an artificial diet for Cylas spp rearing was developed. Studies on the life cycle of Blosyrus spp. were started.

Other achievements included the development of photographic material for use in the identification of pests and symptoms of attack in national surveys; the release of several shipments of natural enemies for control of cassava pests; the exchange of more than 300 000 cassava and sweet potato seeds, representing more than 100 families, among collaborators; and the distribution of 30 sweet potato lines in tissue culture to national programs. By April 1991, eight national programs had evaluated both seed populations and tissue culture material, and selections from these were multiplied for distribution to farmers. Support continued in a second phase.

Recipient Institution(s)