美国白蛾在辽宁发生三代的调查及原因

近年来 ,由于受气候条件的影响 ,在辽宁全省范围内普遍发生第 3代美国白蛾Hyphantria cunea。其原因是 :早春温度变化大 ,降水多影响越冬蛹羽化 ,使成虫发生不整齐 ,高峰期不明显 ;幼虫期低温、多雨使孵化期加长 ,幼虫暴食期遇高温 ,使各虫态发育加快 ,期距缩短 ,但对幼虫和卵的发育基本没有影响。因此气温是导致第 3代美国白蛾发生的重要条件。夏季持续高温 ,秋季降温缓慢是决定第 3代美国白蛾出现早晚、数量多少的关键

Investigation and analysis on the occarrance of the third generation of Hyphantria cunea

In recent years,the third generation in Hyphantria cunea occurred widely in Liaoning.The influence of temperature variation in early spring and heavy rains on the emergence of overwintering pupae caused the irregular development of adults and no obvious peak period.Low temperature and heavy rains prolong the hatch stage of larva and high temperature makes the stages shot. So the temperature is the main factor of the third generation occurrence.Continous high temperature in summer and slow drop in temperature in fall are the key factors cleciding appearing time and quantity of the third generation.