Application of Bacillus thuringiensis (H-14) to rice fields by aerial broadcast spraying of entire fields is not economically feasible for most mosquito abatement districts. This paper presents the results of tests based upon the hypothesis that water movement during flooding of rice fields would distribute B. thuringiensis (H-14) from a point-source or from a narrow band applied at the water entrance to a much larger area. Progressive development of the concept employed decreasing the amount and increasing the time of introduction at the point of water entry. The series of experiments demonstrated distribution of toxic concentrations throughout the rice pan and into pans downfield. Application by airplane along a single flight path over the point of water entrance to the field also resulted in distribution of toxic amounts of B. thuringiensis (H-14) over an expanded area.