植物醫學重要診治案例及樹木傷口棲息菌之研究

台大植物醫學碩士學位學程最主要目的是培養出能夠服務農民、改善農業及樹木產業的植醫及樹醫專業人才。本論文以此為目標分為兩大部分：一是植醫及樹醫相關診治案例實作記錄及報告；二是城巿樹木傷口棲息菌之研究。重要植物疫病蟲害診治案例包含雲林、屏東、台北等地區之農業病蟲害案例與台北地區之樹木診治病例。如銹病、白粉病、灰黴病、炭疽病等病害，並使用水瓊脂平台法之藥劑測試方法尋求最佳之處方。蚜蟲、蟎類、粉蝨等蟲害則多使用葉面噴施之方法進行防治之測試。樹木之褐根病及靈芝根基腐等係以莖部淺孔注射作為醫療方法；松樹之松斑天牛以因滅汀與芬普尼進行莖部注射；櫻花流膠以待克利主劑進行流膠部位之注射。另樹木之傷口腐朽則以外科手術進行清創、藥劑之除菌除蟲，再經抗風性RC修補及表面修復。各診治案例皆有藥劑測試之結果與診治後之改善狀況及未來之建議，為日後植醫及樹醫服務累積一定之診治能力及經驗。樹木傷口棲息菌之研究以採集台北地區之八種常見公園及行道樹種之高部位修剪傷口樣本進行分離，包括艷紫荊、台灣欒、阿勃勒、青剛櫟、光蠟樹、榕樹、樟樹及台灣櫸。各以四種培養基，包括馬鈴薯葡萄糖瓊脂培養基(PDA)、酸化PDA、麥芽瓊脂培養基(MEA)及MA+4選擇性培養基進行組織分離及菌量測定。共分離出110個菌株，經固體培養基之體外分泌酵素能力測定，得知其中54個菌株同時具有纖維素與木質素分解能力，可能為軟腐菌或白腐菌。另23個菌株只有纖維素分解能力；9個菌株只有木質素分解能力。經ITS與LSU序列進行分子鑑定與形態對比，54個菌株中以子囊菌佔大多數，達85%。又自54個菌株中，挑選較好培養的12個菌株進行3種樹木木片培養之木材腐朽能力測試，經培養30日後可測得其乾重損失率即為木材腐朽率。結果發現屬於擔子菌之2菌株木片乾重損失率較高達14-16%，子囊菌者則木片乾重損失率約為6-8%，即亦有相當的木片腐朽能力，並能在木片上長出產孢結構。自八種常見公園及行道樹種之高部位修剪傷口進行組織分離、鑑定及菌量測定之結果，發現除了台灣櫸以外，其他7種之傷口棲息菌中，皆以子囊菌為主流，其種數約佔90%，總菌量也佔9成以上，唯在台灣櫸中，子囊菌種數只佔6成，菌量則佔8成以上，種數之多寡與菌量兩者是造成傷口腐朽程度之關鍵。本研究挑選54個菌株中之7個菌株(SR01、SR02、SR10、SR18、SR24、SR30、SR35)進行藥劑測試，選用24.9%待克利乳劑、75%四氯異苯腈可濕性粉劑、25%普克利乳劑、50%蓋普丹可濕性粉劑、25%三泰芬可濕性粉劑、50倍波爾多液。使用含藥培養基與PD3A平台上菌液與藥劑直接接觸之兩種方法進行測試。發現含藥培養基之測試法易受藥劑劑型的影響，菌液與藥劑直接接觸之藥劑測試法則較便利及與可信。結果發現待克利與普克利對於分離之樹木棲息菌有較好之抑制效果，抑制率可達100%和95%。三泰芬於擔子菌有較高於子囊菌之抑制率。而對新北巿新莊林道於2018年施用三泰芬石灰合劑進行傷口保護之腐朽程度調查，發現其腐朽程度皆屬輕度，可以證明其具腐朽預防之藥效。

關鍵字

診治案例；修剪傷口；樹木注射；水瓊脂平台；木材腐朽菌；軟腐菌

並列摘要

The main purpose of the Master Program for Plant Medicine of National Taiwan University is to train professional plant doctor and tree doctor who can serve farmers and the tree industry to improve the plant health. This dissertation is divided into two parts for this purpose: the first is the 50 case reports each with diagnosis and treatment of important plant diseases, tree pests or non-infectious plant diseases; the second is the in-depth research on tree wound inhabiting fungi in urban forest. The important case reports of diagnosis and treatment include crop diseases and insect pests cases in Yunlin, Pingtung, Taipei and other areas and tree diagnosis and treatment cases in Taipei or other area. Major cases are rust, powdery mildew, gray mold, and anthracnose etc. The study uses the water agar platform method to screen the best agent for controlling the pathogens. Aphids, mites, whiteflies and other pests are controlled by conventional foliar spraying. The brown root rot and Ganoderma root and butt rots were cured by shallow-hole trunk injection with difenoconazole as principal fungicide. The Whu-she blood-spotted long-horned Beetle was treated by injecting emamectin benzoate or fipronil as principal insecticide into the stem. The cherry gummosis disease was cured by injecting principal difenoconazole into the gumming points of tree stem. Tree wounds are surgically treated by wound-cleaning, pesticide application to remove the wood rot fungi and insects, then refilled with wind-resistant RC structure and remodelled with natural tree bark. Each diagnosis and treatment case has the results of the controlling test or improving situation and the recommendation for future works, which will accumulate certain diagnosis and treatment ability or experience for the future plant medicine and tree medicine services. For the study of tree wound inhabiting fungi, pruning wound samples from eight common tree species in Taipei areas were investigated, collected and the containing fungi were isolated. They are Hong Kong orchid tree, flame gold-rain tree, golden shower tree, ring-cupped oak, Formosan ash, small-leafed banyan, camphor tree, and Taiwan zelkova. Four culturing media including the potato dextrose agar (PDA), acidified PDA, malt agar medium, and MA+4 selective medium were used for isolating all the available fungi in the wounds. A total of 110 fungal isolates were obtained, among them 54 isolates showing decomposition abilities for both cellulose and lignin, similar to the white rot or soft rot fungi. While 23 isolates can decompose only the cellulose, and 9 isolates can decompose only the lignin. Molecular identification by PCR and ITS or LSU sequencing together with morphological comparison of the 54 soft rot isolates showed that Ascomycetes groups accounted for 85% of them. The major 12 isolates from these 54 ones were cultured on sterilized wood chips of three tree species for 30 days to determine their wood decomposition ability. Results showed that two Basidiomycetes isolates can decompose the wood chip with about 14-16% dry weight loss, while the major Ascomycetes isolates can decompose the wood chip with about 6-8% dry weight loss, expressing their realistic wood rotting ability. From the isolation and identification results of wound rot fungi on eight common tree species in Taipei areas, we find that Ascomycetes fungi are the dominant group, occupying 90 % of the fungal species, except on the Taiwan zelkova tree wounds which is only 60%. On the basis of propagule density in wound, the Ascomycetes fungi are also the dominant group, occupying over 90 % of the propagule, even on the Taiwan zelkova tree wounds is over 80%. The species and propagule dominance of Ascomycetes fungi in tree wounds indicate that they play very important roles in wound rotting in the urban tree ecosystem. Among the 54 soft rot isolates, 7 of them (SR01, SR02, SR10, SR18, SR24, SR30, SR35) were selected for fungicide testing. Six fungicide including 24.9% difenoconazole, 75% chlorothalonil WP, 25% propiconazole, 50 % captan WP, 25% triadimefon WP, and Bordeaux mixture (50X), were selected for the experiments. Two methods were conducted in the test, including the poisoned food medium method and the PD3A platform method in which the fungal mycelial suspension is directly mixed with the fungicide on the harder PDA platform. Results showed that the fungal response in poisoned food medium could be affected by the formulation type of the fungicide. While the PD3A platform method showed the more convenient and reliable results. From the testing we find that difenoconazole and propiconazole have better inhibitory effect on most of the test isolates, with inhibition rate reaching 100% and 95%, respectively. The triadimefon showed a higher inhibition ability to Basidiomycetes isolates than the Ascomycetes isolates. A special investigation of wound protectant field trial at Shin-Chung district, New Taipei City, showed that the application of triadimefon-lime mixture on pruned wounds in 2018 expressed good protection results so far as the wound rot level are lower than those without the protectant.