Flight activity ofHeliothis virescens (F.) females (Lepidoptera: Noctuidae) with reference to host-plant volatiles

Heliothis virescens (F.) females responded positively via upwind flight in laboratory assays to volatiles emitted from methylńe chloride washes of fresh whole leaves of host plants including cotton, tobacco, and a weed species,Desmodium tortuosum (Swartz) de Candolle. Except forD. tortuosum, the response increased positively with dose; the steepest slope occurred with an extract of cotton squares (flower buds). Almost all of the moths that landed on the extract dispenser also oviposited. Moths simulated by extracts from cotton squares exhibited a full array of behaviors (upwind flight, contact with the dispenser, examination of the cloth substrate with antennae, and oviposition) expected of gravid individuals seeking sites to propagate the species.