In organic agriculture, various cover-crops have been used to control weeds. In this study, we have investigated the effect of Vicia tetrasperma (L.) Schred. (Eolchigiwandu) which is native to on major insect pests of pepper. Redpepper seedlings at 8 leaves stage were transplanted in 20th May 2009 into experimental field located in the farm of the department of agricultural biology, Suwon, Korea. A cover-crop cultivation plot was compared with a control plot mulched by black plastic-film. Density of aphids and damaged fruits by oriental tobacco budworm, Helicoverpa assulta, were surveyed ten times from 21 days after transplanting (DAT) to 82 DAT. Fifty and forty pepper plants were sampled to count the density of aphids and damaged fruits by oriental tobacco budworm per a plant, respectively. In current study, three aphid species namely, cotton aphid, Aphis gossypii, green peach aphid, Myzus persicae, potato aphid, Macrosiphum euphorbiae were collected. Overally, the density of aphids on pepper in the control plot was higher than the cover-crop plot. Especially, aphid density increased up to 67.44±26.8 in early stage of control plot, whereas aphid was not found in cover-crop plot. The rate of fruit damage by oriental tobacco budworm was significantly higher in the cover-crop plot than the control plot in early stage of pepper, however damaged fruit rate of pepper in the control plot was significantly higher since the middle of July.