噻虫嗪对丽蚜小蜂寄生烟粉虱的影响
Effects of thiamethoxam on the parasitism of Encarsia formosa Gahan against Bemisia tabaci Gennadius

为了明确噻虫嗪对烟粉虱天敌昆虫丽蚜小蜂Encarsia formosa的影响,在室内模拟田间噻虫嗪灌根和叶面喷雾2种施药方式,研究了施药后丽蚜小蜂的直接死亡率及其寄生Q型烟粉虱的生物学参数.结果表明,经噻虫嗪叶面喷雾后,丽蚜小蜂的死亡率高达98.10%,显著高于其它处理,丽蚜小蜂对烟粉虱若虫的寄生率为5.26%,显著低于其它处理;与清水对照相比,经噻虫嗪处理后丽蚜小蜂对烟粉虱的致死率降低,且叶面喷雾处理大于灌根处理;噻虫嗪灌根和叶面喷雾处理对丽蚜小蜂的羽化率和发育历期均显著影响,但均能显著缩短丽蚜小蜂成虫的寿命.研究表明,噻虫嗪灌根施药方式对丽蚜小蜂的死亡率及寄生率影响较小,可将噻虫嗪灌根施药方式与释放丽蚜小蜂相结合以防治烟粉虱.
In order to explore the effects of thiamethoxam on the parasitism of Encarsia formosa Gahan against Bemisia tabaci (Gennadius), the mortality of E. formosa with foliar spray and systemic treatments of thiamethoxam were studied in the laboratory, and the parasitic parameters of E. formosa against B. tabaci Q biotype were analyzed. The results showed that the mortality of E. formosa was 98.10% under the foliar spray with thiamethoxam, significantly higher than that of other treatments. The parasitism rate of E. formosa against B. tabaci was 5.26% under the foliar spray, significantly lower than that of other treatments. Compared to the control, thiamethoxam could reduce the mortality of B. tabaci parasitized by E. formosa, and the foliar spray with thiamethoxam had higher influence than the systemic treatment. Thiamethoxam had no significant effects on the emergence rate or developmental duration of E. formosa, but significantly shortened the longevity of E. formosa adults. The results indicated that the systemic treatment had little effect on the mortality and parasitism rate of E. formosa, and systemic treatment of thiamethoxam could be applied in coordination with E. formosa to control B. tabaci.