Evaluation of Entomopathogenic Nematodes, Steinernema carpocapsae (Steinernematidae) and Heterorhabditis bacteriophora (Hetrorhabditidae) against Rice Stem Borer Chilo suppressalis (Walker) (Lepidoptera: Pyralidae)

이화명나방 유충에 대한 곤충병원성 선충 Steinernema carpocapsae(Steinernematidiae)와 Heterorhabditis bacteriophora(Heterohabditidae)의 살충효과

The entomopathogenic nematodes, Steinernema carpocapsae and Heterorhabditis bacteriophoTa, were laboratory tested for the control of rice stem borer Chilo suppressalis. When 8 cm long of two rice stems infected by rice stem borers were treated with S. carpocapsae by spray application to the concentrations of 250, 500, 1,000, or 2,000 nematodes/ml, 68.6 $\pm$ 10.0-94.9 $\pm$ 2.6 % control was obtained. When 8 cm long of rice stems infected by rice stem borers were treated with H. bacteriophoTa by spray application to the concentrations of 100, 200, 400, or 800 nematodes/ ml, 91.4 $\pm$ 0.7-100 % control was obtained. On the other hand, when 8 cm long of three rice stems were treated with H. bacteriophora by dipping application to the concentrations of 100 or 200 nematodes/ml, 46.2 $\pm$ 4.7-63.1 $\pm$ 4.7 % control was obtained. Because the moist habitat of rice stems were favorable to nematode survival and searching abilities, entomopathogenic nematode, were confirmed to be a potential biological control agents against rice stem borers.

이화명나방 유충을 방제할 목적으로 이화명충이 가해한 벼 줄기에 곤충병원성선충인 Steinernema carpocapsae와 Heterorhabditis bacteriophora를 살포한 결과 효과가 좋았다. 8cm 길이의 벼 줄기 2본에 S. carpocapsae 250, 500, 1,000, 2,000마리/ml를 살포한 결과 68.6$\pm$10.0~94.9$\pm$2.6%의 치사율을 얻었으며 H. bacteriophora 100, 200, 400, 800마리 ml살포구에서는 91.4$\pm$0.7~100%의 방제를 얻었다. 그러나 3본의 벼줄기를 H.bacteriophora 현탁액에 침적한 경우는 100마리/ml 구에서는 42.6$\pm$4.7%, 200마리/ml구에서는 63.1$\pm$4.7%로 선충의 현탁액을 살포하는 것보다는 치사율이 낮아 효과가 적었다. 벼 줄기는 선충의 생존과 기주 탐색에 좋은 환경을 유지해 주어 곤충병원 성선충은 이화명충의 방제에 유용한 생물적 인자로 확인 되었다.