應用本土分離光桿菌防治入侵紅火蟻

Application of Photorhabdus luminescens on control of the invasive fire ant Solenopsis invicta

李其龍(Chi-Lung Lee)

指導教授 ： 楊景程

國立臺灣大學/生物資源暨農學院/植物醫學碩士學位學程/碩士(2016年)

https://doi.org/10.6342/NTU201610079

摘要

入侵紅火蟻 (Solenopsis invicta，以下簡稱火蟻) 於 2003 年底確認立足臺灣，目前於雙北、桃園、新竹及宜蘭等地區造成危害。本研究欲以本土短尾異小桿線蟲 (Heterorhabditis bravicaudis) 腸道中分離之光桿菌 (Photorhabdus luminescens) 作為資材，採用光桿菌產生之毒性蛋白質進行生物防治測試。口服毒性試驗中，火蟻累計平均死亡率與培養菌液內之總蛋白質濃度相關。總蛋白質濃度 0.5 mg/mL處理組於 9 日後可造成火蟻累計平均 63.84 % 之死亡率；0.25 mg/mL處理組可造成 56.25 %；0.125 、0.05 mg/mL處理組及對照組分別為 31.62、23.40 及 10.86 %。震盪培養完畢後之菌液於室溫下 (26 ℃) 存放，可保有約兩週之殺蟲效力 (火蟻累計平均死亡率 39.93 %)，效力隨存放時間下降，放置 100 日則完全無殺蟲毒性。不同分子量蛋白質餵食試驗中，大於 100 kDa 組及 10-100 kDa 組殺蟲效力 (36.49 及 50.16 %) 與對照組 (6.75 %) 具顯著差異；兩不同大小蛋白質組間則無差異。應用試驗方面，以震盪培養菌液稀釋後澆灌土壤，發現火蟻在處理組與澆灌水之對照組之選擇偏好上無顯著差異，並顯示土壤處理無法對火蟻產生忌避性。以殼芯比 2:1、濃度 1.4 % 海藻酸鈉水溶液、濃度 5 % 氯化鈣水溶液加上 10 % 砂糖配置完成之膠囊，即能吸引火蟻前來取食。餵食 100 粒膠囊後 18 日能造成火蟻 33.31 % 之累計平均死亡率，較餵食 25 粒處理組及對照組顯著 (致死率 16.40 及 12.70 %)，顯示火蟻之死亡率亦受培養菌液劑量影響。未來若欲以此資材及劑型對火蟻進行防治，除需評估施用量並提高膠囊誘引效力與致死力，亦可整合其他防治措施，建立適用於臺灣之火蟻管理架構。

關鍵字

生物防治 ； 膠囊 ； 微膠囊化 ； 光桿菌 ； 入侵紅火蟻

並列摘要

Since first report in late 2003, the invasive fire ant, Solenopsis invicta, has spread at least half of northern Taiwan despite intensive control effort involving bait broadcasting and individual mound injection. Considering limited resources, developing alternative control methods that are more economical is urgently needed. The present study therefore aims to evaluate biocontrol potential of Photorhabdus luminescens, a symbiotic bacterium in entomopathogenic nematode Heterorhabditis brevicaudis. During proliferation P. luminescens yields toxic proteins that possess insecticidal activities, thus serving as biopesticide for pest control. The P. luminescens broth of different protein concentrations (0.5, 0.25, 0.125 and 0.05 mg/mL) were fed to colonies of S. invicta, accumulated mortalities are generally concentration-dependent, except for those treated with the broth containing 0.125 and 0.05 mg/ml protein which showed no difference with control. Control effect of broth is relevant to preserved days under room temperature. Broth preserved for 15 days could cause 39.93 % mortality; 100-day preservation broth displayed no controlling effort. Oral toxicity treatments of different protein molecular weights (greater than 100 kDa and 10–100 kDa) are not significantly with each other. To employ this liquid-based agent, direct broth application and broth embedding measures can be adopted. Behavioral tests showed that ground-dwelling S. invicta displayed no significant preference on control soil over those treated with P. luminescens broth, indicating negligible repellency of the broth. A bait delivery system was designed using microencapsulation where the broth is surrounded by a coating to retain its physical and chemical property. Capsules (4 mm in diameter) were prepared with a formula of core-shell ratio of 2:1, 1.4 % sodium alginate solution, 5 % calcium chloride solution and 10 % sucrose. Treatment of 100 microcapsules application caused significantly higher accumulated mortality (33.31 %), implying that broth dosage is responsible for fire ant mortality as well. When executing this strategy against fire ants, the amount of applied capsules must be evaluated; improvements of attractiveness and lethality are also required. Besides, other control methods can be combined as well to establish an integrated pest management framework.

並列關鍵字

biocontrol ； microencapsulation ； Photorhabdus luminescens ； Solenopsis invicta

參考文獻

施錫彬、蘇冠中。2006。餌劑對入侵紅火蟻防治試驗。桃園農業改良場研究彙報 60: 25-30。

曾鈺芳。2013。評估本土分離光桿菌防治入侵紅火蟻之潛力。國立臺灣大學植物醫學碩士學位學程碩士論文。

卡雷納。2010。以入侵紅火蟻 (膜翅目：蟻科) 覓食習性為基礎研發其抗水性防治餌劑。國立臺灣大學昆蟲學研究所博士論文。

張佑慈。2007。本土光桿菌 0805-P5G 蛋白質分解酵素的純化、特性分析和殺蟲活性測試。亞洲大學生物科技學系碩士班碩士論文。

彭婉堯。2010。本土光桿菌 0805-P5G prtA 基因選殖與在大腸桿菌之表現。朝陽科技大學應用化學系碩士班碩士論文。