山楂粉蝶害虫分布在内蒙、河北、山西、陕西等省。危害桃、杏、李、梨、苹果等多种树木。一年一代,以三龄幼虫越冬。呼市地区四月中旬开始取食,四月下旬到五月上旬食量逐渐增大,严重时,常将树叶吃光,造成大量减产。1982年5月下旬,在内蒙土右旗果园发现大量山楂粉蝶蛹不能按时羽化,体壁破裂时流出褐色或粉白色体液。经检验证明:其病因是由于感染一种核型多角体病毒所致。有 Hawthorn Verbena pests are distributed in Inner Mongolia, Hebei, Shanxi, Shaanxi and other provinces. Endangered peach, apricot, plum, pear, apple and other trees. One generation, the third instar larvae wintering. Hohhot region began feeding in mid-April, early April to early May gradually increased appetite, often, often leaves eaten, resulting in a large number of cut. In late May 1982, a large number of hawthorn chrysalis pupae were found in Tuobei Banner orchards of Inner Mongolia, and were not able to emerge on time. Brown or white body fluids were shed when the body wall ruptured. Proved by the test: its cause is due to infection with a nuclear polyhedrosis virus. Have