With a more intensive, market-oriented agriculture comes the risk of more intensive pest and disease pressures. If Africa's small farmers are to be competitive over the long term, they must acquire new knowledge, skills, and tools that help meet these threats without relying excessively on agrochemicals, monocropping, or single crop varieties, which only increase the vulnerability of agriculture in the face of evolving pests and diseases and global climate change.

Experience and Achievements

CIAT has a long history of helping African farmers combat bean pests and diseases. In the African highlands, the battle has often been waged in exactly the same places where soil degradation is most advanced. This is no coincidence. High population density and land scarcity in such areas has led to nearly continuous cultivation, reducing soil fertility and leaving bean crops more vulnerable to particular pests and diseases.

Fortunately, CIAT's experience in the region has shown that researchers, working in partnership with farmers and NGOs, can develop and widely disseminate integrated pest management strategies. These rely partly on resistant germplasm but also on improved crop and soil management practices. In Rwanda and subsequently Kenya, multidisciplinary teams working under AHI have developed effective strategies for halting major outbreaks of bean root rots and bean stem maggots. Using a predictive model, other countries are anticipating these pest problems through approaches borrowed from similar environments elsewhere in the region.

In northern Tanzania farmer groups and the national bean program, with support from CIAT, are successfully combating the destructive bean foliage beetle by combining local knowledge (of biopesticides, for example) with researchers' findings on such practices as rotation of beans with maize or sunflower. The participatory methods underlying this work enable farmers to help neighboring communities adapt new technologies to their own circumstances. With support from DFID the approach is now being applied to other pest problems in several other African countries.

Battling the Whitefly

Like its research on soils, CIAT's work on integrated pest and disease management increasingly depends on multi-institutional alliances for combating major threats to agriculture in Africa and beyond. One particularly alarming problem is the whitefly and the many viruses it transmits, affecting numerous crop species across the tropics. Researchers are presenting a united front against this threat through the CIAT-coordinated Tropical Whitefly Integrated Pest Management (TWF-IPM) Project, which forms part of the CGIAR's Systemwide IPM Program.

In Africa the global initiative operates through two subprojects. One confronts whitefly-transmitted viruses affecting tomatoes and other vegetable crops in mixed cropping systems of eastern Africa, while the other deals with such viruses attacking cassava and sweet potato in nine countries across the continent.

The urgent task of the first subproject is to head off a crisis scenario of the sort that has already unfolded in Mexico and Central America, resulting in dramatic reduction of farmers' incomes from export-oriented vegetable production. Scientists are working toward this end by using common research methodologies and sharing experience across regions. In the work on cassava, IITA scientists and Ugandan colleagues have succeeded in mitigating a major food disaster in that country, caused by a severe epidemic of the whitefly-transmitted CMD. The multi-partner whitefly team is now repeating this success in Kenya and Tanzania.