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大避债蛾是常见林木害虫,近几年来徐州地区发生面积大,为害严重,我们对此虫的生活习性和发生规律进行了观察和研究,积累了一些资料。我县1979年对此虫进行了飞机防治,同时也开展了此虫预测预报,为大而积飞机防治提供了可靠依据。 一、预测预报 1.根据越冬前后林间虫口密度预测1979年第一代虫口数量:1978年11月和1979年3月在林间进行虫情调查,结果表明,越冬幼虫死亡率较低为39.1％,越冬后雌性幼虫和雄性幼虫为1:2.56,越冬后平均虫口密度为8.37头/株,平均每株雌虫为3.41头。根据以往观察资料,越冬后老熟幼虫和蛹期(4—5月份)天敌甚少,其死亡率不会超过50％。
Large shelter moth is a common forest pests, Xuzhou area occurred in recent years, a large area, serious damage, we have to observe the habits and occurrence of pests observed and accumulated some information. In 1979, the county carried out the prevention and control of this pest, and also carried out the prediction and forecast of this pest, which provided a reliable basis for the prevention and control of large-scale aircraft. I. Forecast 1. According to the population density of the forest before and after winter forecast The number of the first generation of insect population in 1979: In November 1978 and March 1979 in the forest for insect investigation, the results showed that the mortality of overwintering larvae was 39.1 %. After overwintering, the female larvae and male larvae were 1: 2.56. The average population density after overwintering was 8.37 per plant, with an average of 3.41 per female. According to past observations, overwintering larvae and pupal stage (April-May) very few natural enemies, the mortality rate will not exceed 50%.