- 期刊
敏豆苗腐病菌Pythium myriotylum之耐高溫性及對5種殺菌劑之感受性評估
Kidney Bean (Phaseolus vulgaris Linn.) Root Rot and the Susceptibility of thermo-tolerant Pythium myriotylum to Five Fungicides in Taiwan
摘要
敏豆為我國中低海拔山區夏季重要的蔬菜作物，在2021年於南投信義地區試驗田首次分離發現新興腐黴病菌Pythium myriotylum對敏豆造成苗腐病害。經實驗室分離純化病原菌後，以科霍氏法則（Koch's postulates）確認其病原性，並進一步測試其基本性狀與對國內各作物卵菌綱病害防治用藥之感受性。結果發現該病原菌株在35°C時生長速度最快，且於35°C也有助於對敏豆苗期之侵染速率，但40°C時，菌絲生長速率略降。此外以目前推薦防治卵菌綱5種藥劑包括：亞托敏、普拔克、依得利、達滅芬及賽座滅等，對常見因腐黴病原菌（Pythium spp.）引起之苗腐病與本次分離之病原菌進行實驗室藥劑感受性評估試驗，結果顯示上述5種藥劑中以依得利對病原菌的抑制效果最佳，在推薦稀釋倍數下可達100%抑制率，而其餘4種藥劑則對供試病原菌有不同的感受性，如達滅芬對此菌菌絲生長抑制率皆低於20%，顯示所測驗之病原菌可能對部分藥劑具有抗性。未來如要進一步瞭解田間病原菌對現行藥劑之感受性情形，應進一步擴大收集不同地區病原菌菌株進行評估。
並列摘要
Kidney bean (Phaseolus vulgaris Linn.) is an important summer vegetable crop in Taiwan. In 2021, Pythium myrotylum was first reported in Nantou County which caused root rot disease of kidney beans. The pathogen was isolated and determined to meet Koch's postulates, thereby confirming its pathogenicity. In this study, we evaluated the susceptibility of the Pythium myriotylum S13 isolate to fungicides commonly used to control Oomycetes. We determined that Pythium myrotylum (1) grew most rapidly and (2) exhibited higher kidney bean infection rates at 35°C. We also evaluated the susceptibility of Pythium aphanidermatum (also the causal agent of seedling rot) and Pythium myrotylum to fungicides currently used to control these pathogens (according to a literature review), including azoxystrobin, propamocarb, etridiazole, dimethomorph, and cyazofamid. Results showed that etridiazole had the best inhibitory effect, for example, the inhibition rate of mycelial growth of tested pathogens by dimethomorph is less than 20%, while the pathogens showed different susceptibilities to the other four fungicides. This finding indicates that Pythium myrotylum might have resistance against some fungicides. In conclusion, to better understand the susceptibility of Pythium spp. to currently-used fungicides, further study should be conducted on more isolates collected from different fields.