山楂园东方灰蚧的防治答山东省高请县读者董昌佐东方灰蚧在山楂上主要危害幼树，在虫口密度较小的情况下，可不进行化学防治，而注意保护瓢虫、草蛉、寄生蜂等天敌。虫口密度较大时，可采用触杀作用强的敌杀死等药剂防治。药剂防治的关键时期：一是越冬代若虫出蛰盛期；二... Hawthorn Park Oriental gray scale prevention and control answer Gaozhu County, Shandong Province, the reader Dong Changzuo Oriental gray scale in the hawthorn on the main harm to saplings in the case of population density is small, without chemical control, but pay attention to the protection of ladybugs, Caochao, parasitic Bee and other natural enemies. Insect mouth density, can be used to kill the enemy to kill and other agents to prevent. Pharmacy prevention and control of a crucial period: First, overwintering generation nymph out of stagnation; two ...