EFFECTIVENESS OF DIFFERENT SEED BAITS AND BAITING METHODS FOR WIREWORMS (COLEOPTERA, ELATERIDAE) IN SWEET-POTATO

Several baits an baiting techniques were compared in fields of sweetpotato, Ipomoea batatas (L.) Lam., for sampling wireworms of different species: Conoderus scissus Schaeffer, C. rudis (Brown), C. amplicollis (Gyllenhal), and C. falli Lane. The baits were seeds of corn, wheat, a corn-wheat mixture, rape, cowpea, sorghum, and triticale. These baits were compared with nonbaited soil samples. The relative performance of different baits varied with condition of the baits and length of exposure. The com-wheat mixture attracted more wireworms than the other baits. In the baits, significantly more wireworms were found in the 0-10-cm profile than in the 10-20 and 20-30-cm profiles. No definite relationship was observed between kind of seed bait and wireworm species. Baits removed 1 wk after emergence contained significantly more wireworms than similar baits removed 2 and 3 wk after emergence in fields dominated by C. scissus and C. amplicollis. In a field dominated by C. rudis, more wireworms were found following increased exposure of the bait. Bait plants were equally effective following placement in the field at either 1 or 2 wk after germination. Two-week-old bait plants were less effective except the corn-wheat mixture, which was equally effective 3 wk after germination.