腐霉菌Pythium splendens引起之馬拉巴栗苗木病害

安寶貞(P. J. Ann) ； 陳麗鈴(L. L. Chern) ； 蘇俊峯(J. F. Su) ； 楊正偉(C. W. Yang) ； 蔡惠玲(H. L. Tsai) ； 蔡幸君(H. C. Tsay) ； 蔡志濃(J. N. Tsai) ； 謝廷芳(T. F. Hsieh)

《植物病理學會刊》 23卷3&4期 (2014/09) Pp. 285-292

https://doi.org/10.6649/PPB.201409_23(3_4).0006

摘要

自2011至2013年，經由田間、編辮場及集貨場調查，腐霉菌主要為害馬拉巴栗（Pachira macrocarpa）的編辮苗及集貨場貨品，造成苗木失編與外銷貨品腐敗。腐霉病菌經由切根傷口入侵，造成根部與莖基部組織褐化腐敗，導致部分或全部編辮苗的死亡，在降雨季節，發病率可達30-50%，甚而更高。此外，病菌可為害苗圃幼苗根系，在發病初期，植株地上部病徵不明顯，嚴重時下位葉黃化落葉繼而死亡，而地下部罹病主根則凹陷、縊縮，且罹病組織褐化腐敗。目前自苗圃、編辮場及集貨場等26個場地檢測得腐霉菌，共分離得腐霉菌26株，均鑑定為Pythium splendens。該菌不產生孢囊，只形成球狀厚膜孢子。單株培養不形成有性世代，為異絲型，藏卵器球形或近似球形，每個藏卵器可被1-3個藏經器附著。在8-35℃下皆可生長，最適生長溫度為28℃。接種結果顯示，腐霉菌不易侵入健康苗木組織，但可由傷口入侵，在24-28℃下發病嚴重，為造成編辮苗失編的主要原因之一。本文為世界首度報導證實P. splendens可為害馬拉巴栗。

關鍵字

馬拉巴栗 ； 腐霉根腐病

並列摘要

Based on the survey in the fields, braiding houses and packaging houses from 2011 to 2013 in Taiwan, a Pythium species was found to cause the major diseases of Malabar chestnut (Pachira macrocarpa) including braided seedling root rot and commodity root rot. The pathogen infected seedlings through the wounded root systems causing death of part or all of the braided seedlings. During raining season, the disease incidences of braiding seedlings might up to 30-50% or more and caused serious economic loss. Pythium species also attacked the underground parts of seedlings resulting in the main root constricted and browning, leaf yellowing and premature falling, and seedling death in the nursery stage. A total of 26 Pythium isolates was obtained from 26 locations including nurseries, braiding houses and packaging houses. All isolates were identified as P. splendens. The pathogen did not form sporangia in cultures but produced numerous chlamydospores. The mycelium of pathogen could grow at temperature ranging from 8-35℃ with optimum growth at 28℃. The result of inoculation test showed that P. splendens was one of the major causal microorganisms causing root rot of braided Malabar chestnut seedlings via wounded treatments. It caused disease at 12-32℃ with optimum temperature at 24-28℃. The root rot disease of Malabar chestnut braided seedling caused by P. splendens has not been reported in any other countries prior to this report.

並列關鍵字

Pachira macrocarpa ； Malabar chestnut ； braided seedling root rot ； Pythium splendens