Addis Ababa University, Biology Department, Ethiopia
Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is an exotic stemborer introduced to Africa from Asia some eighty years ago which results in 30-50% grain losses by attacking all stages (seedling, vegetative, flowering and maturity) of the crop in the field. As the case in all exotic pest, the control of C. partellus was attempted through classical biological control by introducing an endo-larval parasitoid, Cotesia flavipes (Cameron) (Hymenoptera: Barconidae) form India and Pakistan. The field release of C. flavipes was done in most of the eastern and southern African countries where C. partellus is a very important pest. However, in Ethiopia the parasitoid established with out release. The population established in Ethiopia might be from the Somalia release of 1997 along the Shebele river. Cotesia flavipes was for the first time recorded in Ethiopia and the 2007 survey showed that the average parasitism rate was 72.5%. The rate growth in parasitism since its establishment is tremendous indicating the success of biological control in suppressing the density of C. partellus. More over, there are a number of pupal and egg parasitoids of C. partellus recorded in Ethiopia. A number of entomopathogens belonging to fungi and nematodes were also isolated from C. partellus in Ethiopia. In summery natural enemies can give sufficient control of C. partellus. However, the naturally occurring bio"=agents should be complemented with other control options such us habitat management (push"=pull) and Varietal resistance among others. Augmentative release of C. flavipes and application of conservation mechanisms should also be done.
Keywords: Ethiopia, stemborer, natural control, integrated pest management