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The ecdysteroid titers of insect growth regulator (IGR)-treated and untreated large milkweed bug nymphs, Oncopeltus fasciatus (Dallas) (Heteroptera: Lygaeidae), were determined by radioimmunoassay. All of the IGRs tested affected the ecdysteroid levels and the ecdysis of both sexes in some way. AI3-63604, a juvenile hormone mimic, accelerated ecdysteroid production and its subsequent decline, shortened the stadium, and induced a supernumerary nymphal molt. Diflubenzuron had no effect on the onset of ecdysteroid production but slightly retarded the decline in ecdysteroid titers before adult ecdysis, and the ecdysis was incomplete. Ecdysteroid production was delayed and erratic in nymphs treated with azadirachtin and AI3-63967, but the effect on ecdysis was different for each compound. Azadirachtin caused incomplete adult ecdysis, whereas AI3-63967 completely prevented any attempts at ecdysis. The large peak of exdysteroid activity associated with apolysis was absent in starved insects, and they made no attempt to ecdyse.

Two sex pheromones have been isolated from the female southern armyworm moth, Prodenia eridania (Cramer), and identified as cis-9-tetradecen-1-ol acetate, identical with the sex pheromone of the fall armyworm moth, Spodoptera frugiperda (J. E. Smith), and cis-9,trans-12-tetradecadien-1-ol acetate.