黄淮海夏玉米区草地贪夜蛾为害籽粒玉米的产量损失与防治阈值

Yield losses and control thresholds of fall armyworm Spodoptera frugiperda on grain corn in Huang-Huai-Hai summer corn region

为确定我国草地贪夜蛾Spodoptera frugiperda重点防范区——黄淮海夏玉米区该虫为害籽粒玉米的防治阈值,于2020—2021年分别在籽粒玉米小喇叭口期(6~8叶)、大喇叭口期(8~10叶)和抽雄吐丝期(12~14叶),通过人工接草地贪夜蛾2龄幼虫进行田间试验,分析不同虫口密度和为害株率下玉米的产量损失,并确定相应防治阈值。结果显示,草地贪夜蛾2龄幼虫密度为2~12头/株时,小喇叭口期、大喇叭口期和抽雄吐丝期的玉米产量损失率分别为16.78%~31.91%、10.45%~25.14%和15.71%~29.17%,在3个玉米生育期对草地贪夜蛾的防治阈值分别为2龄幼虫55~67头/百株、97~118头/百株和59~71头/百株;当草地贪夜蛾2龄幼虫为害株率为5%~60%时,小喇叭口期、大喇叭口期和抽雄吐丝期的玉米产量损失率分别为8.81%~22.43%、4.83%~17.75%和8.16%~20.43%,在3个玉米生育期对草地贪夜蛾的防治阈值为害株率分别为4.24%~5.22%、7.61%~9.49%和4.46%~5.55%。表明黄淮海夏玉米区草地贪夜蛾在不同生育期为害籽粒玉米的产量损失和防治阈值不同。

In order to investigate the yield losses and control thresholds of fall armyworm Spodoptera frugiperda on corn in the key prevention area of Huang-Huai-Hai summer corn region, the second instar larvae of different densities were used to artificially infest corn in the field during 2020—2021 at early whorl stage(6-8 leaves), late whorl stage(8-10 leaves) and tassel and silk stage(12-14 leaves), respectively, and the yield loss caused by S. frugiperda and control thresholds under different larval densities and different infection percentages were studied. The results showed that the yield loss rates were16.78%-31.91%, 10.45%-25.14% and 15.71%-29.17% for 2 to 12 individuals/plant at early whorl stage, late whorl stage, tassel and silk stage, respectively. The control thresholds were 55-67, 97-118and 59-71 individuals per 100 plants, respectively. The yield loss rate were 8.81%-22.43%, 4.83%-17.75% and 8.16%-20.43% under different infection percentages(5%-60%) at early whorl stage, late whorl stage, tassel and silk stage, respectively. The control thresholds were 4.24%-5.22%, 7.61%-9.49% and 4.46%-5.55%(infection percentages), respectively. The yield losses and control thresholds of S. frugiperda were different in different growth stages of maize in Huang-Huai-Hai summer maize region.