Prevalence of microorganisms in field-sampled borers on sorghum, maize, and cowpea in Western Kenya

Abstract

A survey carried out over Western Kenya in order to determine the prevalence of microorganisms in cereal stem borers and legume pod borer showed the presence of a large number of insect pathogens in the dead larvae. Larval cadavers were recovered from all sampling sites. Bacterial and fungal microorganisms were highly prevalent. Other major groups of microorganisms were also recovered, although at a low level. Viruses (polyhedral inclusion bodies and granulosis viruses) occurred at 2.7% at the Mbita Point Field Station, and 1.1% in the field. Mermithids and rhabditids occurred at 0.4% in the station and 0.6% in the field, whereas the protozoans (microsporidia and gregarines) were more prevalent in the station than in the farmers’ fields (9.4 and 1%, respectively). The spotted stalk borer, Chilo partellus was the most common borer sampled, but Busseola fusca and legume pod borer, Maruca testulalis were sampled in most sites too. Sesamia calamistis and Eldana saccharina were recorded at a low level, and C. orichalcoceliellus was recorded only at the Kenya coast.