Discovery of an additional winter host of the soybean pod gall midge, Asphondylia yushimai (Diptera: Cecidomyiidae) in Japan

Asphondylia yushimai, the soybean pod gall midge, completes its annual lifecycle with host alternation between fabaceous plants as summer hosts and Prunus zippeliana (Rosaceae) as a winter host. In the Tohoku District (northern Japan), however, A. yushimai needs an alternative winter host or hosts because the evergreen winter host, P zippeliana, is not distributed in northern Japan. To find additional winter host plants of A. yushimai, five unidentified species of Japanese Asphondylia inducing galls on respective host plants in the winter season were examined based on DNA analysis, morphological observation, and ecological and distributional information. We concluded that Osmanthus heterophyllus (Oleaceae) is a winter host of A. yushimai. This paper reports these findings together with some biological and phenological information on A. yushimai and the winter host. Information on winter hosts will help to discover new control measures against A. yushimai.