Abstract
Three low-level releases of Trichogramma pretiosum (Riley), two at 12,500 and one at 37,500 per ha, at 7-day intervals, did not increase early season Heliothis spp. egg parasitism over that in untreated fields at Natchitoches, La., in 1978. Peak parasitism levels were 59.3 and 40.6% in control and release fields, respectively, but declined before peak egg deposition. Peak natural levels of Trichogramma spp. parasitism in the first Heliothis spp. egg generation in cotton in 1979 at Bossier City and St. Joseph, La., were 89 and 62%, respectively.