草地贪夜蛾幼虫在玉米和小麦上的取食和生长发育特性比较

【目的】评估草地贪夜蛾Spodoptera frugiperda转移至小麦上为害和暴发的风险。【方法】采用室内饲养观察与调查统计的方法,测定和比较了23℃下草地贪夜蛾在玉米和小麦上的取食和生长发育特性及种群生命表参数。【结果】草地贪夜蛾在小麦上可以完成世代,其3龄后幼虫取食小麦的取食量及体重指标显著地高于同处理后时间在玉米上取食的;而食物利用效率、幼虫存活率、幼虫发育历期、卵孵化率均显著低于取食玉米的。取食玉米和取食小麦的草地贪夜蛾的平均蛹重、产卵前期、单雌产卵量等指标间无显著差异。另外,生命表参数比较结果表明,取食玉米和取食小麦的草地贪夜蛾的平均世代周期(T)、内禀增长率(r_m)和周限增长率(λ)间均无显著差异,取食玉米的草地贪夜蛾的净增殖率(R_0)为303.55±2.04,显著高于取食小麦的。【结论】草地贪夜蛾取食小麦时,生长发育速度快,能够完成世代生活史,但其食物利用效率、种群繁殖能力等却均低于取食玉米时,说明草地贪夜蛾更适宜在玉米上取食为害,存在转移至小麦为害的风险,但考虑到虫源、自然温度等条件,草地贪夜蛾在小麦上暴发的风险较小。本研究结果为明确草地贪夜蛾在小麦上为害和暴发的风险以及草地贪夜蛾的科学防控提供了理论依据。

Comparison of the feeding and growth characteristics of larvae of the fall armyworm,Spodoptera frugiperda(Lepidoptera: Noctuidae), on corn and wheat

【Aim】 To assess the risk of damage and outbreak caused by the fall armyworm, Spodoptera frugiperda, shifted to wheat. 【Methods】 The feeding and growth characteristics and population life table parameters of S. frugiperda on corn and wheat under 23℃ in the laboratory were determined and compared by indoor breeding and survey statistics. 【Results】 S. frugiperda could complete its life cycle on wheat, and the food intake and body weight of larvae after the 3rd instar fed on wheat were significantly higher than those fed on corn at the same time after treatment, but the food utilization efficiency, larval survival, larval duration, and egg hatching rate fed on wheat were significantly lower than those fed on corn. There were no significant differences in such indexes as the average pupal weight, pre-oviposition period, and number of eggs laid per female of S. frugiperda fed on corn and wheat. In addition, the comparison of life table parameters showed that there were no significant differences in the mean generation time (T), intrinsic rate of increase (r_m), and finite rate of increase (λ) of S. frugiperda fed on corn and wheat, but the net reproductive rate (R₀) of S. frugiperda fed on corn was 303.55±2.04, which was significantly higher than that fed on wheat. 【Conclusion】 S. frugiperda fed on wheat grows and develops fast and can complete the life cycle. However, the food utilization efficiency and population reproductive ability of S. frugiperda fed on wheat are lower than those on corn, suggesting that S. frugiperda is more suitable for feeding on corn. There is a risk of shifting to damage wheat by S. frugiperda. But considering the source of the pest, natural temperature and other conditions, S. frugiperda is less likely to have an outbreak during damaging wheat. The results of this study provide basic data for clarifying the risk of S. frugiperda damage and outbreak on wheat and the scientific control of S. frugiperda.