臺灣水稻稻麴病之發生與防治藥劑之篩選
Other Title
The Occurrence and Fungicide Efficacy Screening for the Control of Rice False Smut in Taiwan
Journal
台灣農業研究
Journal Volume
74
Journal Issue
1
Start Page
63
End Page
79
ISSN
2790-086X
Date Issued
2025-03-06
Author(s)
Abstract
水稻稻麴病 (Ustilaginoidea virens) 為臺灣水稻次要病害，偶於田間發生，近年來隨著友善耕種觀念普及，水稻有機栽培面積逐年增加，加上受到氣候變遷影響，稻麴病在世界各地均有越來越頻繁且嚴重發生之趨勢，除了影響水稻產量與品質外，其產生之毒素亦可能威脅稻米品質與安全。由於本病害在臺灣發生之相關報告極為有限，本研究於 2022–2023 年在嘉義縣民雄鄉有機水稻田進行 2 年 4 期作之水稻稻麴病害發生率調查，結果顯示稻麴病分別於 2022 年 1期稻作與 2023 年 2期稻作發生，其中又以 2022 年病害發生率較為嚴重，稻欉罹病率最高達 27.5–30.7%，罹病穗率為 9.6–10.6%，罹病穗之稻麴數以 1–2 粒占多數，且多分布於稻穗中下段。另外，自田間所分離之 9 株稻麴病菌菌株，以 potato sucrose agar (PSA) 培養基培養時，其產孢能力、菌落型態及生長速度彼此間具有差異性，其中 6 菌株在 2–4 wk 陸續產生厚膜孢子，但有 3 菌株則完全不產生孢子。進一步挑選 6 株菌落型態不同之菌株進行核酸定序，結果顯示，6 菌株之 internal transcribed spacer (ITS) 序列彼此相同，而與美國國家生物科技資訊中心 (National Center for Biotechnology Information; NCBI) 基因資料庫比對結果則與 U. virens 菌株 118-CLR-KA-40 的 ITS 序列 (Accession no. OL744511) 有高達 99.69%之相似度，鑑定本菌為 U. virens。以交配型基因座 (mating type locus) 之專一性引子對增幅，發現本研究所收集的菌株為 MAT1-1 交配型，並未發現有 MAT1-2 交配型的存在。另挑選其中產孢較穩定之 RSB-5 與 RSB-9分離株進行溫度試驗，結果顯示 25℃為最適合菌絲生長與厚膜孢子發芽之溫度條件。以目前推薦在水稻真菌性病害防治之藥劑對 RSB-5 與 RSB-9 進行室內菌絲生長與孢子發芽抑制試驗，結果顯示百克敏、鋅錳乃浦、克熱淨及免賴得對供試菌株之菌絲生長抑制率最佳，嘉賜黴素抑制率最低；百克敏、甲基多保淨、鋅錳乃浦、克熱淨及免賴得對厚膜孢子具有 100% 發芽抑制率，而嘉賜三賽唑與嘉賜黴素則抑制效果低。綜合以上結果，在水稻孕穗期以百克敏、鋅錳乃浦、克熱淨及免賴得等殺菌劑輪流施藥防治，應可減低稻麴病的危害。
Rice false smut (Ustilaginoidea virens), traditionally a minor disease in Taiwan, has recently become more prevalent due to the increase in organic farming practices and the impact of climate change. This disease not only affects rice yield and quality but also poses a significant threat to food safety due to the mycotoxins. Given the limited reports on the occurrence of this disease in Taiwan, this study was conducted by a comprehensive two-year, four-crop survey of rice false smut incidence in organic rice fields in Minxiong Township, Chiayi County, from 2022 to 2023. The results indicated that rice false smut was present in the first crop of 2022 and the second crop of 2023, with the highest incidence recorded in 2022. The highest hill infection rates ranged from 27.5% to 30.7%, with panicle infection rates between 9.6% and 10.6%. Most infected panicles had 1−2 smut balls, primarily located in the middle to lower parts of the panicle. Nine isolates of U. virens were obtained from the field and cultured on potato sucrose agar (PSA), showing variability in sporulation capacity, colony appear-ance, and mycelial growth rate. Six isolates produced chlamydospores within 2−4 wk, while the other three did not. Genetic sequencing of six isolates revealed identical ITS sequences, 99.69% similar to U. virens isolate 118-CLR-KA-40 (Accession no. OL744511), confirming the identification. Mating type analysis indicated all isolates were belonged to the MAT1-1 type. The study also evaluated the effects of temperature on mycelial growth and chlamydospore germination of the two stable isolates, RSB-5 and RSB-9, with optimal growth and germination at 25℃. Based on the fungicide efficacy tests of mycelial gtrowh and chlamydospore germination of the RSB-5 and RSB-9 isolates, pyraclostrobin, mancozeb, iminoctadine tris, and benomyl showed effective mycelial growth inhibition rates for both isolates, while kasugamycin exhibited the lowest inhibition rate. Additionally, pyraclostrobin, thiophanate-methyl, mancozeb, iminoctadine tris, and benomyl achieved 100% inhibition of chlam-ydospore germination, whereas kasugamycin + tricyclazole and kasugamycin had lower inhibitory effects. These findings suggest that a rotation of pyraclostrobin, thiophanate-methyl, mancozeb, imi-noctadine tris, and benomyl during the booting stage of rice could effectively reduce the impact of rice false smut.
Subjects
水稻
稻麴病
病害防治
Rice
Ustilaginoidea virens
Disease control
Publisher
農業部農業試驗所
Type
journal article
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