Chemical ecology in IPM of important agricultural and livestock pests in sub-Saharan Africa

ICIPE, the International Centre for Insect Physiology and Ecology (www.icipe.org), a pan-African Research and Development Centre, headquartered in Nairobi, Kenya, has been working for four decades on the chemical ecology of major plant and livestock pests in Africa, with the aim of using this knowledge in developing IPM technologies. Landmark examples include the push-pull system (www.push-pull.net), an intercropping technology that involves a cereal, and two perennial companion crops (a fodder grass and a legume), and which addresses three of the main constraints of cereal production in Africa, i.e. lepidopterous stemborer, the witch weed Striga, and low soil fertility. Using push-pull small-scale farmers suppress Striga, largely control stemborers and increase cereal yields 2-4 fold. Another example is icipe’s NGU trap which attracts savannah species of tse-tse flies, Glossina spp. (Diptera: Glossinidae) using both long-range visual (combination of black and blue cloth) and short-range olfactoric attraction (cow urine mixed with acetone). It has been repeatedly used for highly successful spatial tse-tse fly eradication campaigns in Kenya and Ethiopia. A newer tse-tse control approach uses repellants, synthetic and derived from non-preferred hosts like waterbucks, incorporated into a dispenser attached to a collar that cattle are wearing around their neck. This system enables pastoralists to graze their livestock in heavily tse-tse infested areas and protects livestock also from other biting flies (Diptera: Tabanidae). These two examples illustrate how basic knowledge of the behavior and chemical ecology of insect pests can be translated into practical tools for the benefit of African agriculturalists.