Release and establishment of Cotesia flavipes for biological control of maize stemborers in Zimbabwe

Five populations of the crambid stemborer Chilo partellus (Swinhoe) and one of the noctuid borer Busseola fusca (Fuller) from Zimbabwe were evaluated for their suitability for immature development of the exotic braconid larval parasitoid Cotesia flavipes Cameron. Successful parasitoid development occurred only on C. partellus but parasitism as well as egg-to-adult development time did not vary among the five populations. Smallest parasitoid broods, and sex ratios as the proportion of female offspring, however, were produced with C. partellus from the Muzarabani area of Zimbabwe. Co. flavipes became successfully established in five out of eight locations, where it had been released in July 1999 and the 2004/05 summer season. Its spread and impact, however, still need to be assessed.