三化螟种群数量消长原因及防治对策咸宁地区植保站（４３７０００）余学宏三化螟是湖北省水稻上主要害虫之一，一年发生３～４代，以３、４代为主害代，其危害损失轻则５％左右，重则２０％以上。湖北省稻区三化螟种群数量变动，经历了由轻到重，再由重到轻的过程，但近年... The population and growth of the stem borer, its causes and countermeasures Xianning Prefecture Plant Protection Station (437000) Yu Xuehong The stem borer is one of the major pests on rice in Hubei Province. It takes 3 to 4 generations a year, Less about 5% loss, while more than 20%. Hubei Province rice borer population changes, experienced from light to heavy, then heavy to light process, but in recent years ...