摘要：The effects of lower doses including 0.4x, 0.2x, 0.08x, 0.04x, and 0.02x field recommended dose (x) of insecticide fipronil on the emergence of Trichogramma chilonis (Ishii) from the treated larval, and pupal stage of parasitoid within the host eggs of Sitotroga cerealella Olivier , and parasitism of the females T. chilonis were assessed under laboratory conditions. Both 0.4x and 0.2x doses of fipronil led to complete failure of emergence, while the remaining three doses demonstrated ≤ 25.61% emergence in the larval treatment. However, pupal treatment indicated comparatively less toxicity to the parasitoids, i.e., the 0.4x dose showed 3.40%, while both 0.2x and 0.08% doses revealed emergence 29.05, and 39.65%, respectively. Both the lower most doses including 0.04x and 0.02x showed emergence 61.81 and 73.51%, respectively. Fipronil also affected parasitism of the previously treated host eggs of Sitotroga cerealella Olivier, and led to increase in parasitism capacity when dose shifted from high rate toward lower rate: all the used doses demonstrated mean parasitism ranging from 5 to 10.7 except 0.4x dose.
