EMMANUEL OMOGO OGAH1, ADEBAYO A. OMOLOYE2, FRANCIS E. NWILENE3
1Ebonyi State University, Crop Production and Landscape Management, Nigeria
2University of Ibadan, Crop Protection and Environmental Biology, Nigeria
3Africa Rice Center (WARDA), Entomology, Nigeria
African rice gall midge (AfRGM) is one of the major insect pests of rice in Nigeria. Its attacks could result in total crop failure. The dominant pest control strategy in the tropical rice over the past 30 yrs has been in the use of synthetic insecticide, host plant resistance and cultural control. These however have not given the desired results in the control of this insect pest. In order to alleviate growing public concern regarding the effects of synthetic pesticides on human health and environmental impact much attention has been given to biological control recently. Consequently, this study was conducted to determine the efficiency of Aprostocetus procerae in the management of AfRGM. Field evaluations of the potential of A. procerae were conducted at two locations identified as AfRGM endemic areas in Nigeria; ogidiga in southeast and Edozhigi in northcentral during 2006 and 2007 farming seasons. Sampling for O. oryzivora infestation/parasitism was conducted at monthly intervals at both locations from June through November of 2006 and 2007 using farmers' fields. For each field sampling, 50 plants were randomly selected to assess the intensity of damage due to O. oryzivora (percent tiller infestation) and dissected for percent parasitism. All screen house/laboratory evaluations of level of parasitism was conducted at IITA/AfricaRice Ibadan. The results indicated that A. procerae has very high potential for the control of AfRGM. However, the percentage parasitism of the host was low at the beginning of the season and increased significantly later in the season with a peak in October of each season. The linear functional/numerical responses to host densities exhibited by the parasitoid makes it an important factor in suppressing AfRGM population. This result suggests that the use of A. procerae is an important part of IPM programme for the management of AfRGM.
Keywords: Aprostocetus procerae, bio-control, Orseolia oryzivora