湘北烟区烟青虫发生情况研究

Stuay on the occurrence of Heliothis assulta (Gueuee) in northern Hunan

烟青虫在湘北烟区1年发生5代，第一至四代危害烟草，第五代在其他作物上取食。自然条件下，世代重叠比较明显，幼虫发生与危害最大的是第一代，危害时期是5月下旬至6月下旬，同时，还得出了烟青虫各代的发生期、历期及其发育起点温度和有效积温。

The tobacco budworms, Heliothis assulta (Guenee) is occurred five generationt a year inuorthern Hunan. Its first to fourth generation harms tobacco and the fifth eatting on other crops.Under field condition, it has been relatively marked overlapping genetations. In first generation fromlast ten days of May to last ten days of June is the largest amount of larvae and period of seriousdamages. We have also studied the occurrence time, duration, developmental zero and effective accumulative temperature of tobacco budworms for each generation.