关键词: 超低容量喷雾器, 白纹伊蚊, 杀虫剂, 稀释倍数, 雾滴粒径, 防控效果

Abstract: Objective To test the control effects against mosquitoes of ultra-low volume (ULV) spraying of insecticide formulations at various dilution rates and droplet sizes as well as the effective utilization rate of insecticides at various droplet sizes,and to provide a scientific basis for the use of ULV spraying and insecticides.Methods A laser particle size analyzer was used to measure the particle size and differential and cumulative particle-size distributions of ULV spray droplets of insecticide formulations.The control efficacy against Aedes albopictus of Aqua Resigen (S-bioallethrin+permethrin,104 g/L) sprayed at various dilution rates and droplet sizes was tested by hanging cage method under field indoor conditions.SAS 9.2 software was used for one-way analysis of variance.Results When using the ULV1 sprayer to apply Aqua Resigen after 10-,30-,and 50-fold dilution under the label-recommended dose of 0.012 5 mL/m³,the 24-h mortalities of Ae.albopictus were 74.03%,72.95%,and 79.82%,respectively,with no statistical difference (F=0.260,P=0.781).When the sprayer was changed from ULV1 to ULV2 to decrease the droplet size from 80.89µm to 38.28µm,the effective utilization rate of Aqua Resigen was increased from 20.48% to 76.89%,and the mortality was increased from 74.03% to 99.47%.When the test dose of Aqua Resigen was reduced to 0.006 25 mL/m³,ULV2 spraying conferred a 24-h mortality of Ae.albopictus of 98.27%.Conclusion Within a certain dose range,the dilution rate for ULV spraying of the insecticide formulation can be adjusted according to actual needs,which has little impact on the control of mosquitoes.However,the size of ULV spray droplets greatly affects the performance of the insecticide formulation.Increasing the proportion of droplets smaller than 50 μm can improve the control effect and reduce the waste of insecticides.

Key words: Ultra-low volume sprayer, Aedes albopictus, Insecticide formulation, Dilution rate, Droplet size, Control efficacy