【摘要】 对棉铃虫种群动态的多年研究证明 ,棉铃虫年发生世代从 3.3代增加到 4.5代 ,年平均百株累计卵量增加了 4倍。主害代明显后延多发 ,完全 5代出现率已达 2 2 % ,大发生频率巨增。更多还原

【Abstract】 The studies on population dynamic of Helicoverpa armigera Hubner in many years showed that the mean annual generetions has gone up from 3.3 to 4.5 and ovipositing amount on 100 cotton plants incrsased by 400%.Main injurious generations were obvious succeeding and occurring frequently and the arising rate of complete-five-generations had reached 22%,frequency of large-occurring rose greatly.更多还原