2005 年 2005 巻 52 号 p. 115-118
The effects of several insecticides on the predacious natural enemy, Pseudoscymnus hareja (Weise), of the white peach scale, Pseudaulacaspis pentagona (Targioni), were evaluated by laboratory experiments. The larvae of P. hareja for tests were collected from tea fields, these insects were contacted with tea branches dipped in insecticides diluted with water to ordinary use concentration. Imidacloprid and bifenthrin were very harmful and killed all larvae, acetamiprid and acephate were moderately harmful and their emergence rates of treated larvae were 43.7% and 37.5%, respectively. Fenpyroximate+buprofezin mixture, methidathion and chlorphenapyr were almost safe and their emergence rates of treated larvae were from 70.6% to 86.2%. Pyriproxyfen was safe to the larvae and all became to pupae, however, it strongly prevented emergence.