Seasonal Occurrence of Campoletis chlorideae Uchida and Its Control Efficacy on the Oriental Tobacco Budworm, Helicoverpa assulta (Guenee), in Tobacco Fields in Suwon

수원지방 담배포장에서의 Campoleits chlorideae의 발생소장과 담배나방 방제효율

The occurrence of Oriental Tobacco Budworm (OTB), Helicoverpa assulta (Guenee), larvae in early and late planted tobacco fields showed tow or three distinct peaks. The parasitoid, Campoletis chlorideae Uchida, occurred for a short period with one peak following th second peak of OTB in early planted fields. However, in late planted fields, the parasitoid occurred as long as the OTB larvae were abundant. The OTB larval density was higher in late planted fields than in early planted fields. Among four varieties of tobacco, the OBT larval occurrence was relatively high on NC-744 throughout the season. However, more parasitoid cocoons were found in Burleyf-21 and NC-82. The seasonal occurrence of the larval parasitoid, C. chlorideae, assessed by an OTB larval release and recovery method, continued from late June to early September and relatively higher abundance was noticed from early July to late August. In a field cage evaluation of C. chlorideae as a biological control agent of OTB larvae, higher rate of C. chlorideae release (4 females/2$\m^2$) resulted in higher larval parasitism (86.1%) and less leaf damage (8.7%) in tobacco. The leaf damage by OTB larvae was significantly high in the untreatment plot (23.2%) and the lowest damage (1.6%) was recorded in the chemical treatment plot.

담배포장에서 담배나방의 발생은 조식 및 만식 재배구 모두에서 2 또는 3개의 뚜렷한 최성기를 보였다. 반면에 Campoleitis chlorideae는 담배 조식구에서는 담배나방의 두번째 최성기 직후 짧은 기간동안 발생하였으며 만식구에서는 담배나방 유웅이 존재하는 한 발생하였다. 만식구에서의 담배나방 발생은 조식구에서보다 많았다. 4가지 담배 품종중 NC-744에서 담배나방 유충의 발생이 비교적 컸다. 그러나, 기생벌의 발생은 Burley-21과 NC-82에서 많았다. 담배나방 유충의 포장에서의 인위적인 방사 및 재포획법에 의한 결과는 C. chlorideae의 활동은 6월말부터 9월초까지 보였으며 7월초 부터 8월말까지는 비교적 높은 밀도로 발생하였다. C. chlorideae의 담배나방에 대한 생물적방제 수단으로서의 가치평가를 위한 포장내 소규모 케이지 실험결과 방사밀도가 높을수록(암컷 4마리/2 $m^3$) 유충기생률이 높고(86.1%) 담배잎의 피해는 감소함을 보였다.(8.7%) 무처리구에서의 담배잎의 피해는 상당히 높았으며(23.2%) 살충제처리구에서 피해가 가장 낮았다.(1.6%)