覆盆子酮衍生物對瓜實蠅之誘引效力評估及安定性改良

Abstract

瓜實蠅 [melon fly, Bactrocera cucurbitae (Coquillett)] 為葫蘆科作物之重要害蟲，目前在台灣主要使用克蠅 (cuelure) 做為誘引防治資材，但部份文獻指出其有效距離及田間誘殺效能皆未臻理想，故本研究針對另一誘雄物質 raspberry ketone formate (RKF) 進行誘引效能測試及安定性改良。效能評估部分以網籠試驗測試 1、5、10 及 20 日齡雄蟲之被誘引率，結果顯示兩誘引劑於各日齡之誘捕率間無顯著差異，且 24 小時內對未性成熟雄蟲之誘捕率即高於 50%；另標放再捕試驗第 3 天之結果中，於 5、10、20 及 25 m 距離下 RKF 之回捕率均顯著優於克蠅，但至試驗第 7 天時僅於 5 m 及 20 m 距離下具顯著差異。RKF 水解特性探討部分，利用水分滴定儀及高效液相層析儀分析含水量及純度變化，結果指出添加水分含量與樣品靜置室溫 7 天後之 RKF 含量成負相關，而與 RKF 之分解產物覆盆子酮含量成正相關；水解產生之不純物則以網籠試驗進行測試，結果顯示添加 0.1、1、2 及 4% (w/w) 之甲酸或乙酸，對 RKF 及克蠅的誘引效果無顯著影響。安定性提升方面，添加乾燥劑或脫水劑後進行加速儲藏試驗以測試安定效果，結果顯示於閉瓶環境下對安定性無明顯助益；而以開瓶老化試驗測試添加植物油保護劑後 RKF 之分解情形，顯示 10% 及 5% RKF 配方之分解率明顯降低，且可保持 12 週無結晶狀態。田間試驗結果則顯示，10% RKF 植物油安定配方於 8 週試驗期間內之誘引效能顯著高於 50% RKF 及無添加植物油之克蠅與 RKF，但於競爭試驗中與 5% RKF 間則無顯著差異。綜合以上研究結果，RKF 於25 m 釋放距離下之誘殺能力可達克蠅的 1.3 倍，且對性成熟前之雄蟲可產生誘引反應，而經過植物油調配後，可延長誘殺劑使用壽命避免產生結晶、穩定誘引效果並降低 RKF 使用量，具有應用於田間防治作業之價值。

The melon fly, Bactrocera cucurbitae (Coquillett), is an invasive pest of Cucurbitaceae crops worldwide. Currently, cuelure is the main attractant used for male melon flies in attract-and-kill bait traps in Taiwan. However, some studies have indicated that the effective distance and the control efficiency of cuelure to melon flies are not good enough. In order to improve the effectiveness of control programs, the efficacy evaluation and stability elevation of another male lure, raspberry ketone formate (RKF), for melon fly will be studied here. For the efficacy evaluation experiments, rates of melon fly captured in cage experiments were above 50% at 24 hours before the flies had sexually matured, and there were no significant differences among the capture rates of 1, 5, 10, and 20 day-old flies for cuelure or RKF. The results of the mark-release-recapture experiment showed that RKF had a higher accumulated recapture rate on the 3rd day than cuelure at released distances of 5, 10, 20, and 25 m, but the differentiation of capture rates at each released distance were reduced on the 7th day. Investigation of the hydrolytic properties of RKF using moisture and purity analysis showed that, the water content of RKF samples could promote RKF hydrolysis. In addition, when hydrolytic products formic acids and acetic acids were added into RKF and cuelure individually, the results showed no negative effects on capture efficiency at concentrations of 0.1, 1, 2, and 4%. For the stability elevation experiments, adding desiccants showed no significant effects on reducing RKF degradation by accelerated storage method. Nevertheless, adding plant oil could inhibit the crystallization and RKF degradation over the course of 12 weeks, when the proportion of RKF in samples were 5% and 10%. Finally, the RKF formulation at 10% concentration presented the highest effectiveness of those treatments during the 8-week field test. To conclude, the results of the study showed that RKF had higher efficacy than cuelure over long distances, and both lures presented attractiveness to newly emerged male melon flies. Moreover, the longevity, attractive effectiveness, and economic efficiency could be elevated by adding plant oil.