Seasonal Occurrence, Development and Preference of Riptortus pedestris on Hairy Vetch

The seasonal occurrence of Riptortus pedestris Fabricius was investigated using pheromone traps baited with its aggregation pheromone in the fields with various crop composition (mixture culture of barley and hairy vetch in Asan, Chungnam; monoculture of hairy vetch in Yuseung, Daejeon) from mid-May to mid-July of seed gathering season in 2010. The invasion of R. pedestris into the experimental fields began to increase rapidly from late-June in which period hairy vetch and barley reach the beginning of seed formation stage. After seed gathering season in mid-July, the invasion rate of R. pedestris decreased, and the activity was continually observed till early-November. In addition to dominant R. pedestris species, 33 species of hemiptera including Apolyaus watajii, Dolycoris baccarum, Adelphocoris suturalis, and Yemma exlis were collected, which indicated abundant species diversity in the hairy vetch fields. In the laboratory, R. pedestris did not developed successfully to adult stage on food sources of hairy vetch, with decreasing survival rate after 4th instar and the failure of emergence to adult stage. Also, R. pedestris showed higher preference on soybeans than hairy vetch. Consequently, hairy vetch may be not true host for the development and survival of R. pedestris. It is considered that R. pedestris is a temporary visitor at the season of seed formation in hairy vetch fields.