Abundance and diversity of lepidopteran stemborers and their parasitoids on selected wild grasses in Uganda

Surveys were conducted in four agroecological zones in Uganda to catalogue wild host plants of lepidopteran stemborers. Among those sampled, Panicum maximum, Pennisetum purpureum, Pennisetum polystachion and Sorghum arundinaceum were selected for further studies on stemborer diversity and density. Overall, stemborer incidence was low (<10.8%) with the highest infestations on S. arundinaceum. Among the 11 borer species identified, there were seven noctuids, two crambids, one pyralid and one unidentified cossid. The economically important crambid Chilo partellus and the noctuid Busseola fusca were mostly found on S. arundinaceum and were rare on the other three grass species. Braconid larval parasitoids were commonly obtained from C. partellus on S. arundinaceum and parasitoids of Sesamia spp. were most often found on P. purpureum. We concluded that in Uganda, with the exception of S. arundinaceum, wild grasses play a minor role in the seasonal persistence of C. partellus and B. fusca.