|Title:||褐根病之發生、診斷鑑定及防治||Other Titles:||Occurrence, diagnosis and control of brown root rot||Authors:||蔡志濃
|Keywords:||褐根病;生態;防治策略;Phellinus noxius;Phellinus noxius;brown root rot;phylogenetic assay;disease control||Issue Date:||Dec-2010||Publisher:||農業試驗所||Start page/Pages:||147-163||Source:||農業試驗所特刊第149號||Conference:||近年來我國重大作物病害之發生及其診斷、監測與防治研討會專刊||Abstract:||
近年來，台灣許多重要經濟果樹、觀賞植物與林木常發生生長衰退、落葉、萎凋而終至枯死之現象。已證實主要原因為罹患褐根病(brown root rot)，病害由Phellinus noxius (Corner) G. H. Cunningham 引起。Phellinus spp. 分類地位屬擔子菌門， 層菌綱(Hymenomycetes) ， 無褶菌目(Aphyllophorales)，刺革菌科(Hymenochaetaceae)，木層孔菌屬(Phellinus)。在分類上分為5 個群(group)，目前有154 個種(species)和67 個變種(form and varieties)。本菌菌絲不具扣子體，在馬鈴薯葡萄糖瓊脂（PDA）上生長時，菌絲初為白色，而後轉成深淺不規則之褐色塊狀。部份菌絲會斷裂成斷生孢子(arthrospores)或特化成褐色的鹿角菌絲（trichocyst），生長溫度為10～36 ℃，最適生長溫度為28～32 ℃，最適生長酸鹼值為pH 4.5～7.0。P. noxius 在自然界於感染的植物上很少形成子實體，於發現之寄主中僅在九種寄主植物上發現子實體，分別為龍眼、荔枝、番荔枝、木麻黃、鳳凰木、樟樹、榕樹、印度橡膠樹及山刈葉等，子實體為不規則之覆瓦狀，反轉孔面朝上，菌絲層初為乳白色至黃褐色，而後褐化成黑褐色或深灰褐色。擔孢子無色透明、單室、橢圓形，大小3.8-6.3 x 1.5-5.0 μm。褐根病的病徵可分為慢性與急性立枯兩種，與其他病菌引起的立枯病徵相似；而根部病徵特異，罹病木材變褐色，腐朽後並長出褐色網狀線紋。病根的表皮上覆有褐色菌絲塊，並黏沾土塊石粒，故稱為褐根病。褐根病菌為多犯性，寄主範圍廣泛，在台灣之寄主記錄超過130 餘種，無論是果園、觀光區、校園、行道樹、或是住家庭院，經常可見到該病害的蹤影。褐根病主要靠健康根與病根的接觸、種苗帶菌、或帶菌病土傳播，病菌可在殘根中存活5-10 年以上。1991-2006 年自台灣各地的33 種寄主植物收集到80 株 P. noxius 菌株。經rDNA 序列分析比對發現，主要分為2 種序列型態，63 個菌株為 type L，序列長度為614 bp 以及17 個菌株為type S 長度606 bp。在菌株親緣分析方面：P. noxius 各菌株間之親緣性距離較近，相同度(identity)皆在99%以上。進一步依據ITS 區域設計專一性引子對， 正向引子PN-1F (5’-agtttgcgctcatccatctc-3’) 和反向引子PN-2R ( 5’-agccgacttacgccagcag-3’)，利用PCR 技術針對供試之P. noxius 菌株進行分子診斷，均可增幅出414 bp 或422 bp 長度之序列片段；其它菌株皆無法增幅出任何片段，且靈敏度可達0.01 ng。進一步以龍眼樹及相思樹根部組織進行田間試驗，亦可在罹病植株增幅出預期之片段。因此本研究所設計之引子對PN-1F/PN-2R 能用來快速診斷褐根病與輔助鑑定P. noxius。試驗室篩選45 種藥劑，選出抑制褐根病菌菌絲生長較佳之藥劑七種， 包括滅普寧(Mepronil) 、普克利(Propiconazole)、三泰芬(Triadimefon)、撲克拉(Prochloraz)、佈生(TCMTB)、依滅列(Imazalil)、三得芬(Tridemorph)等。另外利用尿素3000 ppm 及淹水處理亦能有效防治褐根病。於南投水里地區一發病的葡萄園進行田間試驗，處理方法為，每株3 年生的葡萄灌注三泰芬＋尿素＋碳酸鈣、撲克拉＋尿素＋碳酸鈣溶液，每種藥劑的用量均為每株10 g，將藥劑溶水中，沿根圈樹冠灌注，每三個月灌注一次，防治效果顯著。
In recent years, Phellinus noxius was found to be widespread and destructive on many tree species throughout Taiwan. The disease causes considerable economic losses to growers each year. Phellinus spp. are the members of Basidiomycetes, and they consist 5 groups, 154 species, 67 forms and varieties. The fungus produces a brown colony on potato dextrose agar (PDA) with irregular dark brown lines or patches permeating the culture. Arthrospores and thichocytes, but not clamp connections, are commonly produced in culture. P. noxius is a high-temperature organism (10-36℃) with optimal growth near 28-32 ℃. The fungus prefers acidic conditions and is capable of growth at pH 4.5-7.0. P. noxius produces thin, hard, uneven basidiocarps similar to those found in nature. They are initially yellowish-brown with a white margin and later become brown and then dark gray. In addition to basidiospores, there are scant hymenial setae and narrow setal hyphae inside the basidiocarp. Fruiting body was not common in nature; It has only been founded on infected longan, litchi, sugar apple , bull oak, flame tree, camphor tree, small-leaved banyan, Indian rubber, and Taiwan melicope. Basidiospore produced on artificial saw dust medium is hyaline, single cell, oval, size 3.8-6.3 X 1.5-5.0 μm. Disease symptom of brown root rot were classed into rapid decline and slow decline. Root infected with P. noxius initially exhibits a brown discoloration of the wood just beneath the bark. In advanced stages of decay, the wood develops a soft, stringy white rot with a conspicuous network of brown zone lines. The outer bark surface appears rough because it is covered with a layer of adhering soil particles and brown fungal mycelia. The inner bark is covered with white to brownish mycelial mat. P. noxius has a wide host range; it has been reported on more than 200 plant species in the world and over 130 plant species in Taiwan containing many fruit tree, ornamental tree and forest tree. P. noxius causes decline and death of ornamental trees planted on campuses, sightseeing places, and parks, and around private and public buildings. Nucleotide sequences of ITS1, 5.8S and ITS2 of 80 strains of Phellinus noxius obtained from 33 tree species at different geographic locations in Taiwan from 1991 to 2006 were analyzed. These strains were divided into two ITS types based on the nucleotide length, type L with 614 bp and types S with 606 bp. Majority of the strains belonged to type L. Both type L and type S were present at most counties of Taiwan. In order to develop a pair of specific primers for rapid and accurate diagnosis of the disease associated with the pathogen in the fields, the ribosomal DNA (rDNA) sequences in internal transcript spacer (ITS, including ITS1/5.8S/ITS2) regions from P. noxius and several other soil-borne fungi were studied. Based on the ITS sequences, a set of primers PN-1F/PN-2R was designed. The forward primer PN-1F sequence is “5’-agtttgcgctcatccatctc-3’ ” and the reverse primer PN-2R is “5’-agccgacttacgccagcag-3’ ”. Using PN-1F/PN-2R primers for PCR amplification under a setup condition and the fungal genomic DNA as templates, a distinct 414 bp or 422 bp fragment were amplified form P. noxius, whereas no PCR products can be amplified from other soil-borne fungi tested. The PCR could amplify the fragments recognizable within 3-4 hr when concentration of
purified DNA was higher or equal to 0.01 ng. Meanwhile, similar amplified fragments were obtained when the diseased root tissues of Dimocarpus longana and Acasia confusa from P. noxius infested fields were used as templates. Results presented here suggest that the primer pairs PN-1F/PN-2R can be efficiency in auxiliary identifying P. noxius and accurately and rapidly detecting disease caused by the pathogen in the field. In order to search of effective control measures, potato dextrose agar amended with individual chemical was used to evaluate the effects of different concentrations of synthetic chemicals on suppression of P. noxius. Among the 45 chemicals tested against P. noxius, 25% propiconazole EC was most effective, completely inhibiting the mycelial growth at the active ingredient dosage of 10 ppm. Bordeaux mixtures were also very effective in inhibiting mycelial growth. Another study was conducted to determine survival of P. noxius in infected stems of loquat buried in soil amended with fungicides, fertilizers, or by flooding. Results showed that treatment of soil with urea at 2.0 g/L soil or flooding of soil for 10 days completely eliminated the pathogen in the stems. A field trial was carried out on 3-5 year-old grapes in a field naturally infested with P. noxius in Shuili, Nantou. Results showed that soil drenching every 3 months with the solution containing 10 g 5% triadimefon+10 g urea+10 g CaCO3 in 1 L of water was the most effective treatment with no infected grapevines developed in all the 60 plants after treating for 2.5 years. In contrast, 6 of 42 (14.3%) tested plants in the untreated control were killed by P. noxius in 2.5 years.
|Appears in Collections:||植物病理組|
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