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粘虫是我县三麦后期的重要害虫,过去一直提倡在幼虫二、三龄盛期防治,结果农药的施用面积很大,既增加成本,又污染了环境。通过几年的摸索试验,我们提出:粘虫防治适期可推迟至幼虫四龄盛期。并经一九八四、一九八五两年大面积的实践证明是可行的。一、推迟防治适期的依据(一)粘虫生命表研究结果表明,粘虫在本地区累计死亡率为百分之九十九点八六,其中卵至四龄幼虫期的累计死亡率达百分之九十三点九三。将防治适期推迟至四龄幼虫盛期。可以充分利用四龄前的种群高死亡率,从而压缩化学防治面积,提高生态、经济效益。
Mythimna separata is an important insect pest in the late stage of Sanmai County. In the past, it was advocated in the second and third instar stages of larvae. As a result, pesticide application area was large, which not only increased costs but also polluted the environment. After several years of groping experiments, we propose that the control of the armyworm may be postponed until the fourth instar of the larva. After a large area of practice in 1984 and 1985, it proved feasible. First, postponed the basis for prevention and control (a) the armyworm life table results show that the armyworm cumulative mortality in the region was 99.86%, of which egg to fourth instar larvae of the cumulative mortality of up to 93.93%. The control period is postponed until the fourth instar larvae. It can make full use of the high mortality rate of the population before the fourth instar to compress the chemical control area and improve the ecological and economic benefits.