樹幹及根部淺孔注入殺菌劑混合物用於治療樹木褐根病之研究

Shallow-hole trunk and root injection with a fungicide-containing mixture for controlling brown root rot disease in trees

由於樹木褐根病菌（Phellinus noxius）在亞熱帶及熱帶地區十分猖獗且可危害200種以上的樹木，因此本團隊歷經多年在臺灣植物及樹木醫學學會的支持之下，嘗試研發出一種簡易的樹木藥劑注射法，用以治療此一重大樹木病害。主要的注射藥劑配方BR5，是含有待克利或普克利殺真菌劑，並添加殺蟲劑、抗細菌抗生素、營養劑及界面活性劑所組成。該配方在田間經以淺孔注射之方法，測試是否能有效抑制樹木褐根病的病情。田間最初之試驗是選擇染病初期、根部或莖基部出現新鮮菌絲面的鳳凰木（Delonix regia）及榕樹（Ficus microcarpa），對其菌絲面四周進行淺孔注射，發現可於1個月內完全抑制菌絲面之生長。其後即應用於台中市進行6株染病受保護榕樹之治療試驗，經過3年共5療程之注射，證明可治癒病樹。另一田間注射防治實驗是在台中港榕樹公園，對2株染病多年之大榕樹進行BR5注射治療，共3年3療程，亦證明可讓樹木保持健康，雖然仍有微量病菌殘存於病根或莖基部。本研究並將含有待克利及普克利之殺真菌劑注射於4株大榕樹之莖基部，發現該2藥劑在注射5至15日後可向下移行至少15至30公分，且達到有效抑菌之高濃度，證明淺孔注射可以讓樹皮、韌皮部篩管、形成層、初生木質部等同時接觸藥劑，故讓藥劑有向下移行之分量，並因此可成功抑制根部之病害。雖然本項樹幹及根部淺孔注入殺菌劑混合物用於治療樹木褐根病之方法在技術上十分簡易，但因樹木注射造成的輕微傷口若操作不當仍有感染雜菌之機會，且BR5藥劑的調配及不同樹種注射點的選擇等皆屬專業，故建議仍應由專業之樹木醫師或人員執行相關之樹木注射醫療作業。

"Because the pathogen Phellinus noxius of brown root rot (BRR) disease can infect more than 200 tree species in tropical and subtropical areas, over many years, we have developed a simple tree injection method for curing this disease, under the support from Plant and Tree Medicine Society of Taiwan. BR5, an injection solution mixture containing the fungicide difenoconazole or propiconazole, together with an insecticide, antibiotic, nutrients, and a surfactant, was tested for its ability to effectively inhibit the BRR fungus when injected using a shallow-hole method. Field experiments showed that within 1 month, the BR5 mixture had inhibited the growth of vigorous mycelial mats on roots of the flame tree (Delonix regia) and on the butt of the small-leafed banyan tree (Ficus microcarpa). Subsequent experiments of shallow-hole injection with six large specimens of the small-leafed banyan in the early disease stage in Taichung were also very successful after 3 years and five cycles of shallow-hole injection with BR5. Field experiments on two rare huge specimens of the small-leafed banyan at Taichung Harbor Park also exhibited good results as both of them remained healthy after three cycles of injection in 3 years, although the remained pathogen still coexisted in the tree trunk or roots. Results of a fungicide distribution study on four small-leafed banyan trees showed that after injection of propiconazole and difenoconazole at basal stem, it had moved downwards by at least 15 and 30 cm during the period 5~15 days post-injection, with an effective concentration against the BRR fungus. The advantage of this shallow-hole trunk injection method is that it simultaneously exposes the shallow layers of the bark, phloem, cambium, and xylem to the injected liquid after the injection. This should make translocation of the fungicide through the phloem possible and assist its downward movement to the roots to inhibit the pathogen. The procedures for a shallow-hole injection are very simple. However, concerns about adverse effects of a tree injection such as wound contamination and other side effects should be fully considered. The preparation of BR5 in situ and injection point selection for different tree species also need a lot of training. Therefore, we suggest that such a tree injection method should only be carried out by well-trained personnel or a tree doctor."