Host Suitability and Parasitic Activity of Local Groups of Habrobracon hebetor (Say, 1836) (Hymenoptera: Braconidae) as a Factor in the Management of Lepidopteran Pest Populations in Corn Agroecosystems

Habrobracon hebetor (Say, 1836) (Hymenoptera: Braconidae) is one of the most significant parasitoids of Lepidoptera in agroecosystems, whose role in the biological control and management of pest populations requires a detailed study of the ecological and biological characteristics of local populations. The paper presents the results of a study of the biological features of natural ectoparasitoid populations captured on corn crops in two districts of the Krasnodar Territory (Russia). The host range and parasitic activity of isolated populations against Lepidoptera caterpillars from the families Noctuidae, Pyralidae, and Tortricidae have been evaluated under laboratory conditions. It has been established that there are pronounced differences in host suitability within H. hebetor: one population (pyralid-leafroller) effectively infects the European corn borer, pulse pod borer moth, and leafroller moths, but does not infect the cotton bollworm; the other (owlet-pyralid) actively parasitizes the cotton bollworm, European corn borer, and pulse pod borer moth. High paralyzing activity (up to 100%) and parasitization (up to 91%) have been shown in relation to caterpillars of middle and older ages. In comparative field observations under release conditions, at a release rate of 1400 individuals/ha, damage by the European corn borer was observed in 16% of corn plants in the treated plot compared with 40% in the control plot. Damage by the cotton bollworm was observed in 13% of corn ears in the treated plot compared with 65.0% in the control plot. The data obtained indicate the potential of using local populations of H. hebetor as effective bioagents for biological control of economically significant Lepidoptera pests in agrocenoses.