PHENOLOGY AND PARASITISM OF HARLEQUIN BUGS, MURGANTIA-HISTRIONICA (HAHN) (HEMIPTERA, PENTATOMIDAE), IN SOUTHWEST VIRGINIA

Field plots containing broccoli, mustard, and rape were sampled weekly between June and October in 1994 and 1995 to determine parasitism and phenology of the harlequin bug, Murgantia histrionica (Hahn) (Hemipte ra: Pentatomidae). Naturally-occurring. wild turnips also were sampled in early spring 1995 for harlequin bugs before cultivated crops were planted. Weekly samples of harlequin bug adults, egg masses, and nymph s were field collected and returned to the laboratory. They were maint ained in the laboratory until emergence to recover parasitoids and to determine the parasitization rates. No adult or nymphal parasitoids we re recovered. Two species, Trissolcus murgantiae Ashmead (Hymenoptera: Scelionidae) and Ooencyrtus johnsoni Howard (Hymenoptera: Encyrtidae) , were identified as egg parasitoids, The overall parasitization rates for 1994 and 1995 were 8% and 37%, respectively. Trissolcus murgantia e was more common than O. johnsoni and accounted for 87% and 96% of th e parasitization, respectively, This is the first record of T. murgant iae in Virginia. The harlequin bugs had two and a partial third genera tion a year. Overwintered adults oviposited on wild turnips, where the first generation completed development. The subsequent generation mig rated to cultivated plants in June and July. The second generation com pleted development on cultivated crops producing the adults which over winter.