Incidence of parasitism of pentatomid (Heteroptera) pests of soybean in South Carolina with a review of studies in other states

The incidence of egg and adult parasitism of the most common phytophagous Pentatomidae in soybean was determined in separate surveys between 1975 and 1978 in South Carolina. Parasitism of egg masses of Nezara viridula (L.) by Trissolcus basalis (Wollaston) at Blackville (central Coastal Plain) ranged from 0%-50% (n = 9 masses). Parasitism of egg masses of Acrosternum hilare (Say) by Trissolcus edessae Fouts ranged from 13%-80% (n = 9 masses). Eggs of Euschistus spp. and Thyanta custator accera McAtee were attacked by T. basalis, T. euschisti (Ashmead) and Telenomus podisi Ashmead at Blackville and only by T. euschisti at Pendleton (Piedmont). Parasitism of adult N. viridula by Trichopoda pennipes (F.) in 1975 ranged from 37%-65% at Blackville, 3-13% at Barnwell, 0%-25% at Williams (upper Coastal Plain), and 43%-82% at Dale (lower Coastal Plain) during 4-6 wk sampling periods. Overall parasitism of adult A. hilare by T. pennipes ranged from 0%-54%. Euclytia flava (Townsend) and Euthera tentatrix Lowe emerged from adult T. c. accerra. Prior to entering overwintering sites, adult N. viridula with attached T. pennipes eggs during October and November averaged 53% on Cassia occidentalis L., 38% on Vigna unguiculata (L.) Walpers, and 57% on Crotalaria spectabilis Roth (n = 1,030): An average of 22.3% (n = 112) of overwintering adult N. viridula had at least one T. pennipes egg attached to the cuticle. Species composition of parasitoids was compared with results from related surveys in other southern states. Surveys from Florida, Kentucky, Louisiana, North Carolina, and South Carolina yielded 16 species of parasitoids recorded from 14 species of adult pentatomids; 14 species of parasitoids emerged from eggs of 12 pentatomid species. Trissolcus basalis apparently does not occur outside the range of N. viridula. Trichopoda pennipes is more important on the exotic host N. viridula than its primary native host A. hilare.