Host Preference and Density-based Parasitism of Three Trichogramma Parasitoid Species in Chilo partellus Swinhoe and Atherigona soccata Rondani

The efficacy of three Trichogramma parasitoid species (T. chilonis, T. minutum and T. carverae) was assessed in two important global agricultural pest species (Chilo partellus and Atherigona soccata) which may result in high densities with massive yield reductions and potentially adverse economic impacts of billions of dollars. The loss of these pests can considerably reduce the yields of agricultural produce. The overall mean parasitism of both insect species was 74.16% for T. chilonis, 58.33% for T. carverae and 50.83% for T. minutum. Significant differences in host-parasitoid interaction were observed. The highest level of parasitism was achieved by T. chilonis in both insect species, followed by T. carverae and T. minutum. Both host species encountered three parasitoids at varying ratios (host: parasitoid), indicating that increased host-parasitoid numbers led to increased parasitism. The overall parasitism in all the cages of C. partellus was 70, 66 and 58% for T. chilonis, T. carverae and T. minutum, respectively, whereas A. soccata parasitism was 70, 62 and 52%, respectively. The current findings support the recommendation to include these species in pest control programs to enhance ecosystem health.