Safety assessment of selected biopesticides and botanicals on Trichogramma spp. (Hymenoptera: Trichogrammatidae) in fields

A biological alternative to pesticides in agriculture is an important subject as it promotes environmental health. Unlike synthetic persticides, they do not harm other beneficial insects and natural enemies of pests. Here, we studied the influence of five biopesticides/botanicals [Dipel WP (Bacillus thuringiensis var. kurstaki), Myco-Jaal 10% SC (Beauvaria bassiana), entomopathogenic nematode (EPN), Steinernema feltiae), Neem azal 1% (10000 ppm azadirachtin) and Karanj oil 2% (20000 ppm karanjin)] on adult emergence and the parasitisation efficiency of Trichogramma spp. in basmati rice. Our results revealed that all the biopesticides/botanicals tested at varied doses against adult emergence of the Trichogramma spp were harmless to slightly harmful, though negative relationship between dose and the emergence was observed. Neem azal 1% @ 5.0 mL/L and karanj oil 2% @ 20.0 mL/L affected the adult emergence of Trichogramma chilonis and T. japonicum negatively. The parasitization efficiency of the surviving individuals was not affected in all the treatments. However, exposure of 2-fold doses of biopesticides i.e., neem azal 1% @ 10.0 mL/L and karanj oil 2% @ 40.0 mL/L, significantly disrupted the adult emergence of T. chilonis and T. japonicum though, the surviving individuals showed the same oviposition ability resulting in successful parasitism. The order of toxicity of different biopesticides/botanicals against Trichogrammatids was Neem azal 1% > Karanj oil 2%> Dipel WP > EPN > Myco-Jaal 10% SC.