PINK-BOLLWORM (LEPIDOPTERA, GELECHIIDAE), CABBAGE-LOOPER, AND BEET ARMYWORM (LEPIDOPTERA, NOCTUIDAE) PUPAL SUSCEPTIBILITY TO STEINERNEMATIDNEMATODES (RHABDITIDA, STEINERNEMATIDAE)

Laboratory studies were conducted to determine the susceptibility of p ink bollworm, Pectinophora gossypiella (Saunders), cabbage looper, Tri choplusia ni (Hubner), and beet armyworm, Spodoptera exigua (Hubner), pupae to 2 species of entomopathogenic nematodes, Steinernema riobravi s Cabanillas, Poinar and Raulston and S. carpocapsae (Weiser). Uninjur ed pink bollworm pupae or pupae with a completely formed integument we re not susceptible to nematode infection (>95% moth emergence). Pink b ollworm pupae with pin-inflicted punctures, injuries from handling or incomplete integument formation, were susceptible to nematode infectio n. Uninjured cabbage looper and beet armyworm pupae were susceptible t o infection by both nematode species. Spiracular orifices of cabbage l ooper and beet armyworm were elliptical in shape and larger than the c ircular shaped pink bollworm spiracular orifices. Spiracular orifice s urface areas of cabbage looper pupae were larger than beet armyworm su rface areas and beet armyworm were larger than those of pink bollworm. The results suggest a partial explanation for the lack of susceptibil ity of pink bollworm pupae to nematode infection.