运用通径分析法探讨了影响第2代玉米螟种群动态的影响因素 ,结果证明 ,影响第2代玉米螟幼虫发生量的关键因素首先是7月26日至31日的降水日数 ,降水日数长短与第2代玉米螟幼虫发生为害程度呈负相关 ;其次为卵期赤眼蜂的寄生率 ,该因素是控制第2代玉米螟种群数量的关键因素之一。8日降水日数多有利于第2代玉米螟幼虫的发生 The path analysis method was used to explore the influencing factors on the population dynamics of the second generation corn borer. The results showed that the key factors influencing the second generation corn borer larvae were the precipitation days from July 26 to 31 and the days of precipitation Which was negatively correlated with the degree of damage to the 2nd generation corn borer larvae, followed by the parasitism rate of Trichogramma ostriniae, which was one of the key factors controlling the population of the 2nd generation corn borer. The number of precipitation days on the 8th is more conducive to the second generation of corn borer larvae