Study on Identification and Best Control Period of Scale Insect (Homoptera, Diaspididae) in Northern Sichuan

Walnut scale insects are seriously harmful in some areas of northern Sichuan, mainly harming the trunk and branches of walnut trees, as well as petioles and veins when the situation is serious. Through morphological and molecular identification, the insect was identified as the Pseudaulacaspis pentagona (Targioni-Tozzetti) and it occurred twice a year in this area. The juvenile nymphs period was from early April to mid-May and from mid-September to mid-October, which was the best time to control this insect in the area.