柑橘類揮發物誘引柑橘木蝨的可能配方探討

Abstract

亞洲柑橘木蝨 (Diaphorina citri Kuwayama) 為柑橘黃龍病的主要傳播媒介，其傳播黃龍病造成柑橘產業重大損失。本研究嘗試找尋木蝨具偏好性的化合物以製作誘引劑，期望能將誘引劑結合黃色黏板，以提升黃色黏板偵測木蝨族群之靈敏度與可信度，冀能使氣味結合黃色黏板成為高效誘殺器，進一步解決亞洲柑橘木蝨在防治時機與藥劑使用上的問題。試驗首先選擇 4 種氣味 (兩種柑橘類精油與兩種離體植株嫩葉) 之揮發物作為誘引氣味基礎資材，利用 Y 型管測試柑橘木蝨之偏好性，再以氣相層析質譜儀 (GC-MS) 進行樣本化合物分析，嘗試尋找最有潛力之誘引成份以進行後續分析，最終再以黃色黏板結合具顯著偏好性資材以半田間方式測試其誘捕率。試驗結果顯示，四種柑橘類氣味中柑橘木蝨僅以 62.18% 選擇顯著偏好甜橙精油的揮發物，以甜橙精油主要八種揮發化合物依照 GC-MS 分析比例，配製的 4 種濃度人造氣味柑橘木蝨皆不具偏好性，且僅以 100 ppm 濃度樣本效果較為正向，因此以其配置法為基礎，依序個別剃除其中 1 種化合物，發現柑橘木蝨以 37.43% 與 37.14% 的選擇率顯著不偏好個別剃除檸檬烯 (Limonene) 與瓦倫烯 (Valencene) 後混合物的氣味，推測此兩種化合物可能為關鍵化合物，之後分別以原始 100 ppm 混合物中相對單獨檸檬烯 (Limonene)、單獨瓦倫烯 (Valencene) 的含有量另外配置 1000 ppm~1 ppm 四種序列稀釋濃度混合物進行木蝨偏好性測試，結果發現柑橘木蝨僅以 62.64% 對 100 ppm 之檸檬烯與瓦倫烯混合物產生顯著偏好；黃色黏板結合甜橙精油或 100 ppm 之檸檬烯與瓦倫烯混合物進行組合試驗，結果顯示甜橙精油組黃色黏板捕捉量在 7.5 hr 後開始有捕捉數量的顯著差異並維持至試驗結束，而 100 ppm 檸檬烯與瓦倫烯混合物則在 3.5 hr 後開始有捕捉數量的顯著差異並維持至試驗結束。顯示甜橙精油揮發物中的檸檬烯與瓦倫烯化合物具有發展誘引劑的可能性，可作為後續開發柑橘木蝨誘引劑之基礎。

The Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) is the main vector of Huanglongbing (HLB), the disease responsible for the severe destruction of citrus industry in many countries. This study aims to investigate attractive compounds for combination with yellow sticky trap to improve the control efficiency of ACPs. Four odors of citrus (two essential oils and two young leaves of citrus) were subjected to GC-MS analysis and Y-tube olfactometer bioassay to test the response of ACPs to individual odors. The results showed sweet orange essential oil is a better odor which could significantly attract more ACPs (62.18%). The main eight components derived from sweet orange essential oil were then chose to blend mixtures with various concentrations for Y-tube olfactometer bioassay and the results suggested that 100 ppm mixture better attracts ACPs. After the single compound removal experiment, Limonene and Valencene in sweet orange essential oil were identified as the key components which could attract over 60% ACPs (attract only 37.43% and 37.14% ACPs when Limonene and Valencene were removed from the blend mixtures respectively). Further test showed that 62.64% ACPs were attracted to 100 ppm mixture of Limonene and Valencene. Semi-field studies revealed that yellow sticky trap combined with sweet orange essential oil or mixture of Limonene and Valencene could steadily attract more ACPs after 7.5 hours and 3.5 hours respectively. To sum up, sweet orange essential oils or its components Limonene and Valencene were the potential candidates for development of ACPs attractant.