Populations of the bollworm,Heliothis zea(Boddie), and the tobacco budworm,H. virescens(F.), and 8 arthropod predators were studied following in-furrow and sidedress applications of aldicarb and foliar applications of monocrotophos to cotton. In 3 field tests, the arthropod predator populations were reduced but there were increases inHeliothisspp. infestations. The reduction in predator populations apparently was not great enough to cause all of the increases inHeliothisspp. that occurred. When tobacco budworm moths were given a choice between cotton in field cages treated with a sidedress application of aldicarb and foliar applications of monocrotophos and untreated cotton, the moths preferred to oviposit on the cotton treated with the insecticides.