The goal of this project is to screen Arizona-native and commercially available EPN to find the best "species- match" for controlling citrus nematode, and the evaluation of the effect of different EPN concentrations and application time on the penetration and egg production of T. semipenetrans . Assessment of this information is critical for understanding EPN-citrus nematode interactions and in making predictions of the various impacts of EPN application for the control of this nematode.