Laboratory fecundity as predictor of field success in Trichogramma carverae (Hymenoptera: Trichogrammatidae)

Laboratory fecundity assessments are routinely used to determine the quality of commercially reared Trichogramma egg parasitoids before release for pest control, but there is little information on the relevance of this trait to the field success of Trichogramma. Herein, we characterize the parasitism success of strains of Trichogramma carverae Oatman & Pinto in the laboratory on a factitious (Sitotroga cerealella Olivier) and a natural (Epiphyas postvittana Walker) host. Differences in fecundity of the strains in the laboratory were consistent with a heritability of approximately 10%, allowing ranking of the strains from highest to lowest fecundity. The strains with particularly high and low fecundities were tested for successful parasitism in the field. Results of the field releases show that strain differences in laboratory fecundity did not influence field performance. The implications of this result for fecundity as a quality indicator for commercial stocks are discussed.