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Study on survival of Phellinus noxius in the field and diseased tissue
brown root rot disease,Phellinus noxius,survival,fungicides injection,fungicides drenching,soil amendment,
|Publication Year :||2018|
|Abstract:||由 Phellinus noxius 引起之樹木褐根病為台灣最重要之樹木病害之一，除造成樹木萎凋死亡及經濟損失外，亦會威脅民眾生命及財產安全，是迫切需要防治及管理的樹木病害。褐根病菌殘存於木材組織作為感染源為樹木褐根病傳播的主要途徑之一，因此降低或除滅土壤及病組織中殘存之病原菌為褐根病管理中相當重要的課題。本研究旨在篩選防治褐根病可用的新藥劑，並探討藥劑注射、土壤藥劑澆灌或土壤改良劑處理對於褐根病菌殘存之影響。本研究將馬拉巴栗幼苗接種褐根病菌 PN401 菌株，用來模擬藥劑注射及殘存試驗。馬拉巴栗接種褐根病菌並發病後，埋在 BVB 栽培介質中1個月，仍可自組織再分離到褐根病菌。六種供試藥劑分別為亞派占、亞托環克座、貝芬四克利、白列克收欣、三泰隆及普克利。經稀釋平板法測試，有效成分濃度10 ppm 之亞派占、亞托環克座、貝芬四克利、三泰隆和普克利對褐根病菌菌絲生長抑制率可達100%，白列克收欣在1000 ppm 時抑制率僅77.4%。馬拉巴栗接種褐根病前，將六種受試藥劑稀釋1000倍進行預防注射，以亞派占、亞托環克座、白列克收欣及三泰隆較能有效抑制褐根病菌感染。而在治療性注射試驗中，任何藥劑經1000倍或100倍稀釋後注射，均無法有效防治褐根病。將馬拉巴栗接種褐根病後剖半作為模擬殘根，埋入 BVB 栽培介質並進行土壤藥劑澆灌、土壤改良劑及淹水處理，其中以淹水處理效果最佳，兩批次試驗分別於7天及3天後偵測不到褐根病菌殘存，菜籽粕處理效果次之，在第二批次試驗中於3天後檢測不到褐根病菌殘存。將罹病之田間榕樹殘根埋入 BVB 栽培介質，並進行亞派占、貝芬四克利、萄萄糖-麩胺酸之澆灌、菜籽粕混拌及淹水處理，其中仍以淹水處理之效果最佳，處理後1個月即無褐根病菌殘存，其他處理則無顯著之效果。田間褐根病病株經藥劑注射後，經採樣發現莖基部組織中褐根病菌之殘存率有下降之趨勢，但無法將褐根病菌完全除滅。罹病樹頭及病區土壤經藥劑澆灌處理，經採樣檢測褐根病菌殘存率亦有下降之趨勢，其中麵包樹樹頭基部在處理後近10個月已分離不到褐根病菌，但樹頭地下根部組織中褐根病菌之殘存情行仍屬未知，有待進一步研究探討。|
Brown root rot disease caused by Phellinus noxius is one of the most important tree diseases in Taiwan. In addition to causing decline of trees and economic loss, brown root rot disease also posts threat to people’s lives and property, which make it urgently needed for disease management. Long-term survival of P. noxius in infested wood tissue as primary inoculum is one of the main pathway for disease spreading. Therefore, it is critical for brown root rot disease management to reduce or eradicate the survival of P. noxius in infested tissue and soil. This study is aimed at selecting new fungicide available for disease control and evaluating the effects of trunk injection, soil drenching and soil amendment on survival of P. noxius. Seedlings of Malabar chestnut (Pachira aquatica) were inoculated with P. noxius (isolate PN401) for fungicides injection test and survival test in this study. P. noxius could be isolated from diseased tissue of Malabar chestnut which had buried in BVB substrates for 1 month. Fungicides including isopyrazam, azoxystrobin + cyproconazole, carbendazim + tetraconazole, boscalid + kresoxim-methyl, triadimenol and propiconazole are tested for their inhibition on P. noxius in this study. Mycelial growth of P. noxius was completely inhibited on the dilution PDA plate with 10 ppm isopyrazam, azoxystrobin + cyproconazole, carbendazim + tetraconazole, triadimenol or propiconazole, while the inhibition rate of mycelial growth only reached 77.4% on dilution plate with 1000 ppm boscalid + kresoxim-methyl. The 1000-fold dilution of each tested fungicide was preventively injected into the basal stem of malabar chestnut before inoculation with P. noxius. Isopyrazam, azoxystrobin + cyproconazole, boscalid + kresoxim-methyl or triadimenol treatment showed good control efficacy for P. noxius, while therapeutical injection after inoculation with the same fungicides showed no effect on disease control. Malabar chestnut stem infected with P. noxius was bisected, buried in BVB substrates and treated with fungicides drenching, soil amendment, or flooding. Flooding treatment showed the most effective on eradicating P. noxius which could not be isolated from infested tissue after 7 days or 3 days in two replicate tests. Rapeseed meal treatment also showed good effectiveness and eradicated P. noxius in 3 days in one replicate test. Root debris of Chinese banyan (Ficus microcarpa) infested with brown disease in fields was collected, buried in BVB substrates and treated with suspension of isopyrazam, carbendazim + tetraconazole, glucose-glutamate solution, rapeseed meal or flooding. The flooding treatment still showed the most effective on eradicating P. noxius which could not be isolated from root tissue after 1 month treatment, while other treatment showed no significant effects. Trees in fields were injected with fungicides for controlling brown root rot disease and tissue at basal stem was sampled. After injection, the survival rate of P. noxius in diseased tissue was reduced gradually but not eradicated. Diseased stumps and soil were drenched with fungicides and sampled. Results showed that the survival of P. noxius at stumps also reduced. At the stump of Artocarpus altilis, P. noxius could not even be detected. However, survival of P. noxius at deep root tissue is still unknown and should be studied in the future.
|Appears in Collections:||植物醫學碩士學位學程|
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