烟田中静电喷雾和电动喷雾下噻虫嗪的防效及对昆虫群落的影响

【目的】探明静电喷雾与电动喷雾对噻虫嗪防治害虫效果及烟田昆虫群落的影响,为静电喷雾在烟草上的推广应用提供理论依据。【方法】利用静电喷雾与电动喷雾法喷施0.66 g·L~(-1)25%噻虫嗪水分散粒剂,施药1、3、7 d后,测定2种方法对烟蚜与斜纹夜蛾的防治效果、在烟株与土壤中的沉积以及对昆虫群落的影响。【结果】喷施25%噻虫嗪水分散粒剂1、3、7 d后,静电喷雾对烟蚜和斜纹夜蛾的防治效果均显著高于电动喷雾的防治效果,且防治效果均随时间的推移而升高。噻虫嗪在静电喷雾处理区烟叶上的沉积量高于电动喷雾处理区烟叶上的沉积量,而在静电喷雾处理区土壤中的沉积量低于电动喷雾处理区土壤中的沉积量,且都随时间的推移而降低。静电喷雾与电动喷雾均引起烟田昆虫群落的变化,静电喷雾引起的害虫和中性昆虫的数量变化大于电动喷雾,但天敌昆虫的数量变化小于电动喷雾,且静电喷雾区烟田的物种丰富度明显高于电动喷雾区,可见静电喷雾施药对烟田昆虫群落的影响小于电动喷雾施药。静电喷雾的S_t/S_i与S_n/S_p比值明显高于电动喷雾,说明静电喷雾烟田中昆虫群落稳定性高于电动喷雾烟田中昆虫群落的稳定性。【结论】相比电动喷雾,静电喷雾能够提高噻虫嗪在烟叶上的沉积量,从而提高噻虫嗪对害虫的防治效果,同时减少噻虫嗪在土壤中的沉积量,提高噻虫嗪的生态安全性,因此,静电喷雾在烟草病虫害防治上具有较好的应用前景。

Effects of electrostatic spraying and electric spraying on thiamethoxam control and insect community in tobacco fields

Aim] To investigate the effects of electrostatic and electric spraying of thiamethoxam on pest control and the insect communities in tobacco fields and provide a theoretical basis for the application of electrostatic spraying on tobacco.Method] The control efficiency of thiamethoxam against Myzus persicae and Spodoptera litura, its deposition on tobacco plants and on soil, and its effects on the insect community were determined after spraying 25% thiamethoxam (0.66 g·L^-1) 1, 3 or 7 days with an electrostatic and an electric sprayer.Result] One, 3 or 7 d after spraying thiamethoxam oxazine, the electrostatic spraying of thiamethoxam oxazine had significantly higher control effects on M. persicae and S. litura than electric spraying, and these control effects increased over time. The amount of thiamethoxam deposited on the tobacco leaves in the electrostatic spray treatment area was higher than in the electric spray treatment area, while the amount of thiamethoxam deposited in the soil in the electrostatic spray treatment area was lower than that in the electric spray treatment area, and both decreased with time. Both electrostatic and electric spraying caused changes in the insect communities in the tobacco fields. The changes in the numbers of pests and neutral insects caused by the electrostatic spraying were greater than those caused by the electric spraying. However, the change in the number of natural enemy insects caused by electrostatic spraying was less than that caused by electric spraying, and the species richness in the electrostatic spray zone of the tobacco fields was obviously higher than that in the electric spray zone. The visible effect of electrostatic spraying of the pesticide on the insect community in the tobacco fields was less than that of electric spraying. The S_t/S_i and S_n/S_p ratios of the electrostatic spray treatment were significantly higher than those of the electric spray treatment, which indicated that the stability of the insect community in the electrostatic sprayed tobacco field was higher than that in the electric sprayed tobacco field.Conclusion] Compared with electric spraying, electrostatic spraying can increase thiamethoxam oxazine precipitation and, thus, enhance the pest control effect, while simultaneously reducing its soil deposition, thus, improving its ecological safety. Therefore, electrostatic spraying has good application prospects for tobacco pest control.