亞滅培對荔枝細蛾田間防治效果評估

Evaluation of the control effect of acetamiprid on litchi fruit borer (Conopomorpha sinensis Bradley) in the field

荔枝細蛾是荔枝栽培過程的一種重要害蟲。為評估亞滅培應用於荔枝，對於荔枝細蛾是否具良好防治成效，本研究於高雄市大樹區，以20%亞滅培水溶性粉劑2,000、4,000及5,000倍稀釋藥液對荔枝細蛾進行防治（效果）評估，並以2.8%第滅寧乳劑作為對照藥劑。本研究除了調查鮮果受荔枝細蛾危害比率（以下簡稱受害率），亦針對鮮果落果率與受害率，以及地上落果中的荔枝細蛾羽化成蟲數進行評估。結果顯示，各處理植株雌花謝花後7-10天的小果，即逐漸受到荔枝細蛾危害，且不施藥對照組自施藥前至施藥後第5週，其受害率逐漸提高。於第3次施藥後，亞滅培處理組的受害率顯著低於第滅寧與不施藥對照組。第4次施藥後28天，第滅寧處理組受害率已高達52%，但20%亞滅培水溶性粉劑2,000、4,000及5,000倍稀釋處理組的受害率僅介於5.5%～8%，且無顯著差異。此外，本研究亦發現荔枝的落果率與受害率成正相關。依研究結果建議施用20%亞滅培水溶性粉劑4,000倍，於荔枝雌花謝花後7-10天內著手進行防治。

Litchi fruit borer moth (Conopomorpha sinensis Bradley) is the most important pest of litchi cultivation in Taiwan. To evaluate the efficacy of acetamiprid against C. sinensis, a field experiment was conducted to evaluate the effect of 20% acetamiprid water-soluble power (SP) on C. sinensis of litchi, in Dashu District, Kaohsiung City. Three dilution treatments (2,000, 4,000, and 5,000) of the 20% acetamiprid SP were applied, while the 2.8% deltamethrin emulsifiable concentrate (EC) was applied as a control. The litchi fruit infestation rate and fallen rate caused by C. sinensis, and its adult emergence rate in the fallen fruit were surveyed. The results showed that the small fruits, 7-10 days after the female flower faded, began to be infested by the C. sinensis in each treatment, and the infestation rate gradually raised through five consecutive weeks. After the 3^(rd) application, the infestation rate of the acetamiprid treatment was significantly lower than the deltamethrin and pesticide-free control groups. Twenty-eight days after the 4^(th) application, the infestation rate of the deltamethrin treatment reached 52%, while the infestation rate of the three dilution factors of 20% acetamiprid was 5.5% - 8%. The current study also revealed a positive correlation between the infestation rate and the fallen fruit rate. In summary, the current study recommended that adopting the 4,000 times dilution treatment of 20% acetamiprid SP within 7-10 days after the litchi female faded flowers would be an ideal management protocol of C. sinensis.