Percentage hatch, chewing predation,Chrysopasp. predation, other sucking predation, and parasitism byTrichogrammasp. of egg masses of first-generationOstrinia nubilalis(H¨bner) were estimated in spring chisel plow, ridge tillage, and no-tillage maize,Zea maysL., in southeastern Minnesota during 1986 and 1987. Tillage plots were split with and without terbufos application and with and withoutBacillus thuringiensis-permethrin application in all combinations. Egg masses from laboratory rearedO. nubilaliswere exposed to natural enemies in the field eight times during the oviposition period of first-generationO. nubilalis, and population densities ofColeomegilla maculataDeGeer were estimated. Parasitism was 0.6% and predation was low during 1986. During 1987, chewing predation was highest in the chisel-plow system and lowest in the no-tillage system;Chrysopasp. predation was lowest in the chisel-plow system and highest in the no-tillage system.C. maculatapopulation densities were highest in the chisel-plow system and lowest in the no-tillage system, and chewing predation was positively related toC. maculatadensity. Predation by other unknown chewing predators was also higher in the chisel-plow system and lowest in the no-tillage system. The inverse relation between chewing andChrysopasp. predation was probably related to species specific responses to the tillage environments.