1. National Institute of Agro-Environmental Sciences, Tsukuba 305-8604, Japan.
2. National Institute of Sericultural and Entomological Science, Tsukuba 305-8634, Japan.
3. Yokohama Plant Protection Station 5–57, Kitanaka-dori, Naka-ku, Yokohama, Kanagawa 231-0003, Japan.