柑橘嫩葉揮發物具誘引柑橘木蝨潛力之研究

Abstract

亞洲柑橘木蝨 (Diaphorina citri Kuwayama) 為柑橘黃龍病的媒介昆蟲，感染黃龍病的植株目前仍無藥劑根治，因此預防植株患病更為重要，台灣已建立健康種苗制度，並持續推行，能避免黃龍病經嫁接傳播；國內外針對媒介昆蟲，研究各種防治方法，仍無良好監測方式，有效預防木蝨，因此，本研究目的為人造誘引木蝨物質，希望能結合黃色黏板，改善田間監測方式。室內試驗結果顯示，不同柑橘品種的嫩葉中，木蝨最偏好椪柑，其次為柳丁，藉由 GC-MS 分析柑橘嫩葉成分，再次確認椪柑與其他品種嫩葉成分有別，後續則藉由 Y-型管，進行揮發物的偏好性試驗。首先，測試木蝨對柑橘嫩葉成分的單一揮發物之偏好性，雖然超過 50% 的木蝨選擇α-蒎烯 (α-pinene)、傘花烴 (p-cymene) 和β-羅勒烯 (β-ocimene)，經統計無顯著差異，因此將多種揮發物進行混合，模擬椪柑嫩葉的揮發物種類和比例，配製人造誘引劑 1，與控制組比較後，無顯著差異；更改配方的揮發物種類和調整比例與濃度，配製人造誘引劑 2 進行試驗，63.9% 的木蝨選擇以橄欖油作為溶劑的人造誘引劑 2，統計上仍未達顯著差異。人造誘引劑偏好性試驗結果雖然不理想，但確實觀察到木蝨傾向選擇人造誘引劑的現象，說明以嗅覺刺激作為開發木蝨誘引劑的方式仍可行，只是有待更進一步的實驗，提高誘引劑的吸引程度。

Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an important vector of Huanglongbing (HLB), a phloem-restricted bacterial disease that hammered citrus industry worldwide. To date, there is no chemical cure for the infected citrus crops. Prevention is therefore far more important than cure concerning HLB. Taiwan has established healthy seedling system, which meant to cut off HLB transmission via grafting. Nevertheless, citrus orchids are vulnerable to HLB by insect vector, ACP. Chemical control is the common way to deal with ACP, but excessive use of insecticide not only give rise to resistance, but also damage environment. Improvement of current monitor methods may lead to better understanding of ACP colony distribution in citrus orchards. With enhanced monitor method, the use of insecticide will be more efficient. Our goal is thus analyzing volatile organic compounds (VOCs) from citrus young leaves, and by combining VOCs that attracts ACP, we hope to find mixtures that can be used along with yellow sticky traps. We first looked into ACP preference of young leaves on different citrus cultivars. Meanwhile, we analyzed VOCs from young leaves and compared with the result of ACP preference. Ponkan is the most preferred cultivar, and the content of its young leaves also showed clear difference with other cultivars. Then, based on the information above, we formulated two mixtures, artificial attractant 1, and 2. After preference tests using Y-tube olfactometer, even 63.9% of ACP chose artificial attractant 2, there is no analytic significant difference. The results are negative though, still prove the possibility of making mixtures that attract ACP based on VOCs from citrus young leaves.