害虫の疾病に関する研究(第2報) : ニカメイガ幼虫における黄きよう病の病徴について

In winter, 1957, experiments were made to observe the symptoms of the rice stem borer, Chilo suppressalis WALKER exhibited by inoculation of the conidia of Isaria farinosa (DICKS.) FR., and to examine the relation between these symptoms and the environmental temperature.
The symptoms were found in the following order.
1) Formation of black spots : the larvae infected with the conidia developed black spots, which centered mainly in their abdomens and legs.
2) Coloration : the color of the body infected turned red. This change began at the caudal part and gradually extended all over the body.
3) Development of aerial hyphae : after the coloration, aerial hyphae appeared at the caudal part and joints, and gradually covered the whole body.
At more than 20℃ no statistical difference was observed in the duratioh of any coloration hyphal development. The duration, however, was prolonged at 16℃ or 12℃.