Trypsin Modulating Osstatic Factor (tMOF) is a deapeptide that is the physiological signal that terminates trypsin in biosynthesis in mosquito gut epithelial cells. TMOF has recently been shown to passs through adult and larval guts and circulate in the hemolymph. Prior results from our laboratoy demonstrated that feeding tMOF or TMOF that is expressed as part of the coat protein of Tobacco Mosaic virus (TMV) to mosquito larvae halted trypsin biosynthesis by gut epithelial cells causing starvation and up to 100% mortality. We now propose to further develop the TMOF tecchnology into a commercial product for use as a birational insectiocide to control mosquito populations and mosquito carryiing diseases. We will accomplish this by cloning and expressing TMOF in Chlorella cells that are ubiquitously present in water wheere mosquitoes commonly breed and serve as a native food source sor mosquito larvae. Larval death and inhibition of trypsin biosynthesis will be monitored after feeding mosquito larvae live and heat inactivated chlorella cells that synthesize TMOF and compare them with controls that do ot produce TMOF. We will also evaluate the length of time (number of generations) that the extrachromosomal element containing the TMOF generations) that the extrachromosomal element containing the TMOF genetic information is effectively reproduced by the Chlorella.