Parasitism ofHeliothis1Eggs After Field Releases ofTrichogramma pretiosum2in Cotton34

Abstract

Individual releases of 19,000–387,500 Trichogramma adults per acre on up to 48 acres of cotton at College Station, Tex., resulted in parasitism of Heliothis eggs averaging from 33–81%, with some movement of parasites up to 400 ft within 2 days. Subsequent generations of Trichogramma were not produced in the field due to mortality, apparently caused by drift of methyl parathion (ultra-low volume) which killed 75% of the adult Trichogramma at distances of up to one mile downwind from sprayed fields.