50%呋虫胺对入侵害虫扶桑绵粉蚧的室内毒力及田间药效

Virulence and Field Efficacy of 50%Dinotefuran Water Dispersible Granules on the Invasive Pest,Phenacoccus solenopsis Tinsley

【目的】为评估50%呋虫胺水分散粒剂对扶桑绵粉蚧的防治效果。【方法】采用喷雾法进行50%呋虫胺水分散粒剂的室内生物测定和田间药效试验。【结果】3龄幼虫、成虫的致死中浓度LC50值分别为25.8297 mg/L、49.5898 mg/L,显示了对扶桑绵粉蚧有较强的毒力。田间药效试验显示,相同的处理时间,呋虫胺对扶桑绵粉蚧的防效与浓度呈正相关;C1(0.125 g/L)、C2(0.167 g/L)处理在药后7 d达到最高防效,14 d后防效下降;C3(0.2 g/L)、C4(0.25 g/L)和C5(0.5 g/L)防效与药剂浓度和处理时间呈正相关,C5的防治效果最好,药后3 d、7 d的校正防效显著高于其他浓度的同期效果,药后14 d的防效为92.08%,显著高于C1、C2和C3,与C4差异不显著。【结论】研究表明,50%呋虫胺水分散粒剂可有效防治扶桑绵粉蚧。在进行防治时,综合考虑防治效果、防治成本及生态环境保护等因素,建议使用C4进行防治,当绵粉蚧虫口基数较大时,可在药后10~14 d进行2次用药。

[Objective]This study was conducted to evaluate effects of 50%dinotefuran water dispersible granules on Phenacoccus solenopsis Tinsley.[Method]Indoor virulence and field efficacy experiments of 50%dinotefuran water dispersed granule were carried out by spraying method.[Result]The LC50 values of the 3rd instar larvae and adults of mealybugs were 25.8297 mg/L and 49.5898 mg/L,respectively,indicating the pesticide had strong virulence to mealybugs.Field experiments showed that the efficacy of dinotefuran on P.solenopsis was positively correlated with the concentration at the same time,with the best after 7 days at the treatment of C1(0.125 g/L)and C2(0.167 g/L),and then decreased after 14 days.The efficacy of C3(0.2 g/L),C4(0.25 g/L)and C5(0.5 g/L)was positively corrected with the concentration and treatment time.It had the best efficacy under the treatment of C5(0.5 g/L),which was significantly higher than that of other concentration at 3 days and 7days after treatment.The efficacy of 14 days after treatment was 92.08%,which was significantly higher than that of C1(0.125 g/L),C2(0.167 g/L)and C3(0.2 g/L),and was not significantly different from that of C4(0.25 g/L).[Conclusion]Studies have shown that 50%dinotefuran water dispersible granules can control P.solenopsis effectively.Considering the prevention and efficacy,costs,and ecological environmental protection,it is recommended to use C4(0.25 g/L)to control mealybugs in the field.While,when the number of the pest becomes large,secondary medication can be used after 10 to 14 days.