Three lepidopterous stem borers were reported on maize in Ethiopia. Although complete crop loss is evident in some areas, the average yield loss of maize caused by cereal stem borers in Ethiopia can be estimated between 20 and 50%. A resource-poor farmers produce over 87% of maize, inexpensive, ecologically sound and effective cereal stem borer control methods are indispensable. To this end, surveys and field experiments were conducted in 1999 and 2000. Surveys were conducted in major maize growing areas of eastern, western, southern and northern Ethiopia. In the surveys, four stel1 borers, 20 species of parasitoids, 14 species of predators and seven entomopathogens were investigated. These natural enemies gave about 18% re<1:uction of cereal stem borers. Of these natural enemies Cotesia flavipes Cameron (Hymenoptera Braconidae) alone gave 13% reduction. Intercropping of maize with beans significantly (P<O.O1) reduced density per plant of stem borers and increased the diversity and parasitism of the parasitoids. Some maize lines were also found to be resistant to cereal stem borers. In conclusion, conservation/augmentation of the natural enemies existing in the agro-ecosystem of maize and the use of intercropping are the best options of cereal stem borer management in Ethiopia. Besides, work on varietal resistance should be continued to identify the best resistant genes which can be incorporated into commercial maize varieties with desirable agronomic traits such as high yield and disease resistance.

English

0409|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection