亚洲玉米螟越冬关键生物控制因子研究

连续4年对沈阳地区亚洲玉米螟Ostrinia furnacalis(Guenée)越冬幼虫越冬后存活及发育情况研究表明,亚洲玉米螟幼虫越冬死亡率在45%～65%之间;白僵菌Beauvaria bassiana、寄蝇和茧蜂是导致亚洲玉米螟幼虫越冬死亡的主要病原菌和天敌种类,3类生物致死因子的综合控制力为22.50%～34.11%;3种生物致死因子年度间组成比例变异较大,存在互补和竞争效应,越冬后发生时期不同,白僵菌主要发生于发蛾高峰期前,茧蜂羽化期在发蛾高峰期后,寄蝇羽化期晚于白僵菌而早于茧蜂,白僵菌有越冬后再次侵染越冬代幼虫的条件;亚洲玉米螟室温下羽化期为18 d左右,雄蛾羽化和结束时间早于雌蛾,雌雄性比年度间差异较大。

Key Lethal Factors of Overwintering Generation Larvae in the Asian Corn Borer (Ostrinia furnacalis)

Survival and development of overwintering larvae of the Asian corn borer (ACB), Ostrinia furnacalis, was surveyed in the Aprils of 2009 to 2012 to clarify the key lethal factors and the development trends after winter in Shenyang area. Results showed that mortality of ACB overwintering larvae ranged between 45%-65%, resulting from biotic and abiotic factors. The main natural biocontrol elements of the overwintering larvae were the white muscardine fungus (Beauvaria bassiana), a braconid wasp (Macrocentrus cingulum) and a tachinid fly (Lydella grisescens), which resulted in mortality ranged between 22.50%-34.11%. The three natural elements accounted for varied ACB mortality among years, but a complementary or competitive effect could be noticed. The occurrence of the three natural enemies was different, white muscardine appeared before peak of moth eclosion, braconid wasp appeared after the peak of moth eclosion, and the tachinid fly came in between. White muscardine fungus has the potential to infect other healthy overwintering larvae. Eclosion period of the Asian corn borer at room temperature was around 18 d, eclosion start and end were earlier in male than in female. The sex ratio varied among years.