The fungal pathogen Lagenidium giganteum (California isolate), cultured on sunflower seed extract (SFE) and agar, was introduced once (May 15) into outdoor caged replicated stagnant water pools containing all instars of larval Culex quinquefasciatus. Subsequently, first-instar larvae were added daily (May 15-September 30) to simulate natural oviposition. The fungus persisted for the entire 138-day study period, which corresponded with the season of Cx. quinquefasciatus breeding in this region of North Carolina, and recycled in the mosquito larvae producing an 82% reduction of adult mosquitoes produced in comparison to untreated pools. The cycles of fungal activity varied among the pools with 2-4 major epizootics occurring during the study period. Data are presented on the cycling of populations of fungal zoospores, mosquito larvae, pupae and adults during the entire mosquito breeding season.