不同作业方式和施药模式下杀虫剂对褐飞虱的防治效果

为探讨植保无人机施药沉积利用率高但防治效果不稳定的问题，利用液相色谱串联质谱法测定植保无人机和背负式喷雾器喷施后药液在水稻植株上的农药沉积率，选择烯啶虫胺、吡蚜酮、呋虫胺和毒死蜱4种杀虫剂分别对分蘖期和拔节期水稻进行不同施药模式的室内喷施试验，以模拟分析水稻非靶标部位的农药沉积对褐飞虱防治效果的影响。结果表明，植保无人机喷施后水稻中上部的农药沉积率为34.83%，显著高于背负式喷雾器的农药沉积率（15.30%），但药后7 d的校正防治效果分别为61.4%和64.4%，两者之间差异不显著。烯啶虫胺、呋虫胺和吡蚜酮3种内吸性杀虫剂室内模拟喷施后1 d和4 d均为直接喷施处理的水稻基部农药含量最高，且该处理药后1、4和7 d的校正死亡率最高，分别为23.33%~70.00%、46.67%~80.42%和70.00%~87.50%；其次为遮挡茎部喷施处理，而水中加药和叶片受药处理的防治效果最差。对于兼有触杀和熏蒸毒性的有机磷类杀虫剂毒死蜱，水中加药处理和直接喷施处理药后1、2和4 d的校正死亡率均在98.33%以上，显著高于其他2种处理。表明不同杀虫剂的吸收传导特性不同，这直接影响其能否到达水稻基部，进而影响其对褐飞虱的防治效果。

Control efficacies of insecticides against the brown planthopper Nilaparvata lugens under various field operation modes and indoor application patterns of insecticide spraying

To explore the problem of higher utilization rates of pesticides with unstable control efficacies using the agricultural unmanned aerial vehicle (UAV) sprayer, the deposition rates of pesticides on rice plants were determined with liquid chromatography-tandem mass spectrometry after the field spraying operations by UAV and knapsack power sprayer (KPS), respectively. Four insecticides (nitenpyram, pymetrozine, dinotefuran and chlorpyrifos) were selected to carry out the laboratory experiments of insecticide spraying through various application patterns for the simulation analysis of the effects of off-target pesticide deposits on the control efficacies of insecticides against the brown planthopper Nilaparvata lugens in paddy fields. The results showed that the deposition rate of pesticide on the middle-upper section of rice plants was 34.83% by UAV application, which was significantly higher than KPS (15.30%). However, their corrected control efficacies on the seventh day after treatment (DAT) were 61.4% and 64.4%, respectively, and no significant differences existed between these two operation modes. In the laboratory simulation applications of insecticide spraying, the maximum pesticide contents assessed in the base samples of rice plant were observed in the direct spraying treatments for all three systemic insecticides (nitenpyram, dinotefuran and pymetrozine) on both first DAT and fourth DAT. Their corresponding corrected mortalities were also the highest in all treatments on first DAT (23.33%-70.00%), fourth DAT (46.67%-80.42%) and seventh DAT (70.00%-87.50%), respectively. The spraying with rice stem bottom covered ranked second, while the treatments of spraying leaves and adding insecticides into water had lower mortalities. For the organophosphate insecticide chlorpyrifos with contact toxicity and fumigant action, both spraying directly and adding the insecticide into water resulted in more than 98.33% corrected mortalities on first DAT, second DAT and fourth DAT, respectively, which were remarkably higher than those of the other two treatments. As observed, different insecticides had different characteristics of uptake and translocation, which directly influence whether they could be transferred to the rice stems, thus affecting their control efficacies against N. lugens.