The scientific goal of this research proposal is to demonstrate that larval management using environmentally safe and efficacious microbial insecticides in rice can provide an integral part of a malaria control program. This investigation is designed to develop larval management strategies and new microbial formulations that can provide additional entomological tools to reduce malaria in conjunction with adult control, personal protection, and clinical treatment. This proposal emphasizes attacking anopheline mosquitoes before they become airborne, when they are the most concentrated, immobile and accessible, or basic Integrated Mosquito Management (IMM). The greatest barrier to initiating a larval management program is that larval ecology of African malaria vectors is a neglected area of malaria research. Thus there has also been an associated lack of research in the development and deployment of environmentally safe microbial larvicides, such as Bacillus thuriengiensis var. isrealensis (Bti) and Bacillus sphaericus (Bsph). In order to develop, implement, and maintain a mosquito management program in rice irrigation schemes, we must determine site-specific IMM critical elements; the when, where, and how to reduce adult emergence by larval management. This study will provide both the efficacy data on the impact of microbial control and critical environmental data necessary for registration of new formulations both in the US and in international locations, thus circumventing prohibitive costs to industry. To accomplish this goal, the following specific aims have been developed. 1) determine the spatial and temporal distribution and abundance of Anopheles larval habitats and their vector productivity in irrigated rice-village complexes, 2) determine the key environmental, agricultural, and ecological factors that regulate vector productivity and non-target abundance and diversity in the larval habitats, 3) develop, evaluate and register new microbial-larvicide formulation(s) designed for effective residual control of anopheline larvae, and 4) implement and evaluate the impact of an area-wide mosquito management program on the entomological parameters associated with the transmission of malaria in rice. ? ?