PARASITISM OF PICKLEWORM AND MELONWORM (LEPIDOPTERA, PYRALIDAE) BY CARDIOCHILES-DIAPHANIAE (HYMENOPTERA, BRACONIDAE)

Pickelworm, Diaphania nitidalis (Stoll), and melonworm, Diaphania hyal inata (L.), larvae were susceptible to parasitism by Cardiochiles diap haniae Marsh. Melonworm larvae were more susceptible to parasitism tha n pickleworm, but both exhibited reduced weight gain and head capsule growth in later stadia compared with nonparasitized conspecifics and t hen perished following initiation of wandering before pupal molt. Melo nworm larvae parasitized when in advanced stadia achieved a greater fi nal weight than larvae parasitized when young. Parasitoid larval devel opment time was longest following parasitization of young melonworm, b ut not significantly different in melonworm larvae parasitized in midd le or later instars. Compared with nonparasitized melonworm larvae, th e prepupal wandering stage was abbreviated in melonworm larvae parasit ized when young, and extended in melonworm larvae parasitized in later instars. Overall, parasitoid development time was significantly longe r in pickleworm hosts than melonworm. Adult parasitoid weight increase d with host age at the time of parasitization when melonworm served as host and was highest in middle-instar larvae when pickle-worm served as host. C. diaphaniae developing in pickleworm larvae weighed signifi cantly more than those developing in melonworm larvae.