(p-146)ENVIRONMENTAL STRESS OF MULBERRY LEAVES: FEEDING RESPONSE IN THE LARVAE OF SILKWORM, Bombyx mori

Mitsuo Yazawa, Yoshiko Hirose, Tohru Shimizu, Shigenobu Yoshida, and Ritsuko Hinomoto (Murakami)

National Institute of Sericultural and Entomological Science, 1-2, Ohwashi, Tsukuba, Ibaraki 305, Japan.

1. Damage by diseases of mulberry leaves caused a reduced feeding response in Bombyx mori larvae (ca18% reduction in consumption, as compared with control). Sucrose content of the foliage decreased after infection with pathogens. Feeding response tests in amount of feces or body weights, sucrose concentration (ca. » 46mg/g) showed a reduced response to disease of sucrose contents of the leaves.
2. Ultraviolet irradiation of mulberry leaves caused a reduced feeding response in B. mori larvae (ca. 22% reduction in consumption, as compared with control). Sucrose content of the foliage decreased after exposure to UV irradiation (0.5mW/cm2) for 1hr. As a result, we concluded that the reduced feeding response in B. mori larvae is due to the decreased sucrose content of the mulberry leaves after infection with pathogens or exposure to UV irradiation.