In the laboratory a proprietary, neem-based insecticide formulation (NBI) was evaluated as a potential pest management tool for the western cherry fruit fly, Rhagoletis indifferens Curran (WCFF). NBI was tested for its potential effects on survival and development of juvenile WCFF. Incorporation of NBI into an artificial larval diet resulted in a decrease in the formation of pupae and subsequent adult emergence. Late third instar larvae exposed to NBI in sand were able to form puparia; however, the numbers of adults and pupae developing inside the puparia were decreased at concentrations as low as 0.05% NBI. Well-timed root drenches with NBI could control R. indifferens by disrupting pupation. Applied in this manner, NBI may provide cherry orchardists with an effective, new control tactic.