Parasitism of Heliothis zea and H. virescens (Lepidoptera: Noctuidae) Larvae in Wild and Cultivated Host Plants in the Delta of Mississipp 1

Abstract

Bollworm, Heliothis zea (Boddie), and tobacco budworm, H. virescens (F.) larvae were collected at weekly intervals from 6 April through 28 August 1981 from several species of wild and cultivated host plants in the delta of Mississippi. The species, seasonal occurrence, and abundance of Heliothis larvae and their larval parasites in each species of host plant were determined. Four species of parasites, Microplitts croceipes (Cresson), Cotesia (= Apanteles) marginiventris (Cresson), Cardiochiles nigriceps Vierick, and Campoletis sonorensis (Cameron) were reared from Heliothis larvae. The highest and lowest numbers of species of parasites and percentage of parasitism of Heliothis larvae occurred in species of early season wild host plants. M. croceipes parasitized larger numbers of Heliothis spp. larvae in more species of host plants and was active over a longer period than any other parasite species. The decline in the incidence of parasitism of Heliothis in cotton, Gossypium hirsutum L., and soybeans, Glycine max (L.) Merr., during mid- and late season may have resulted from the rapid and vast expansion in host plant habitat and from applications of insecticides.