石林县玉米田草地贪夜蛾幼虫种群动态及玉米品种抗性研究

Population Dynamics of Spodoptera frugiperda in Maize Field and Resistance of Maize Varieties in Shilin County

【目的】明确草地贪夜蛾[Spodoptera frugiperda(J.E.Smith)]种群动态及发生规律、筛选具有抗虫性的玉米种质资源,有助于对其进行有效防控。【方法】通过5点取样法对30个玉米品种进行了定期、定点、定株的田间系统调查,记录草地贪夜蛾幼虫种群数量、为害部位和龄期,明确幼虫种群数量动态、垂直分布动态、空间分布型及不同玉米品种对草地贪夜蛾种群的抗性。【结果】草地贪夜蛾在玉米整个生育期均能造成危害,抽雄期种群数量达到最高,随着果穗成熟种群数量逐渐减少;不同玉米品种上草地贪夜蛾幼虫种群数量消长趋势大体一致,但发生数量存在差异。不同玉米生育期,幼虫种群在玉米上的垂直分布情况不同,喇叭口期为害上部心叶,抽雄期及以后为害雌穗及其苞叶。草地贪夜蛾种群在玉米抽雄期呈聚集分布,聚集原因为自然因子引起,其他生育期呈均匀分布,总体上呈聚集−扩散−聚集的趋势。受害最轻的品种瑞白6号与受害最重的品种TR151之间的虫情指数相差3.5倍以上。【结论】草地贪夜蛾在玉米整个生育期均能造成危害,发生高峰期为8月上旬玉米抽雄期;不同玉米品种草地贪夜蛾种群数量存在显著差异。研究结果可为石林县草地贪夜蛾种群数量的预测、预报和防控提供依据。

[Purpose]To determine the population dynamics and occurrence rules of Spodoptera frugiperda(J.E.Smith),screening the germplasm resources with insect resistance to help effectively control S.frugiperda.[Methods]A field systematic survey was regularly conducted on 30 maize varieties using a 5-point sampling method with fixed points and plants.The population number,damage location and age of S.frugiperda larvae were recorded,and the dynamics of the larval population,vertical distribution,spatial distribution,and the resistance of different maize varieties on S.frugiperda population were determined.[Results]S.frugiperda was harmful to maize during the whole growth period.The population reached the highest level in tasseling stage,and gradually de-creased with the maturing of the ear.The number of larvae in different maize varieties showed the same trend,but the number of larvae was different.The vertical distribution of larva population on maize was different at different growth stages.The upper heart leaf was harmed at trumpet stage,and the female ear and its bracts were harmed at tasseling stage and later stage.The population of S.fru-giperda showed an aggregation distribution in the maize tasseling stage,which was caused by natural factors.The population of S.frugiperda showed a uniform distribution in other growth stages,form-ing a trend of aggregation-diffusion-aggregation in general.There was a difference of more than 3.5 times between the least damaged variety Ruibai No.6 and the most damaged variety TR151.[Conclusion]S.frugiperda can cause damage throughout the maize growth stage,and its occur-rence peak is the tasseling stage in early August;the population number of S.frugiperda is signific-antly different among different maize varieties.The results of study are beneficial to the prediction and control of S.frugiperda population in Shilin County.