緑肥用オオムギを間作した露地ネギ圃場のネギおよびオオムギにおけるアザミウマ類（アザミウマ目：アザミウマ科）およびキイカブリダニ（ダニ目：カブリダニ科）の発生消長

抄録

We investigated the density fluctuation of Thrips tabaci Lindeman and Gynaeseius liturivorus (Ehara) on Welsh onion and Anaphothrips obscurus (Müller) and G. liturivorus on intercropping barley‘Hyakumangoku’ in 2013 and 2014 in Chiba Prefecture, Japan. Gynaeseius liturivorus densities on barley increased in late July after peak abundance of A. obscurus. Densities of G. liturivorus and T. tabaci on Welsh onion intercropping with barley in late July was significantly higher and lower than on Welsh onion without barley (=control), respectively. Barley plants sowed in late May or early June in this experiment withered in late August. Gynaeseius liturivorus densities on Welsh onion intercropping with barley rapidly decreased after barley plants withered, and it shifted similarly or lower than on control Welsh onion in October to November. Thrips tabaci densities on Welsh onion intercropping with barley shifted equally on control Welsh onion after October. These results indicated that intercropping barley increases G. liturivorus density and decreases T. tabaci density on Welsh onion in late July. However, we need techniques to maintain high G. liturivorus density to control and lower T. tabaci density after intercropping barley plants withered.