Rhizoctonia solani 各菌絲融合羣對馬鈴薯之侵害情形

Abstract

馬鈴薯「五豐」及「克難」兩品種對Rhizoctonia solani 引起之黑痣病均屬感病性。生育後期（80 ~95 天）田間發病率「五豐」為31.2 士3.2 % ，收穫前「五豐」為52.7 士7 %，「克難」為16.4 士3.7 %。R. solani 各菌絲融合群（TRAG）侵害馬鈴薯之比率為：TRAG 1佔9.3 % , 主要由莖部侵入後蔓延至莖基部及塊莖上；TRAG 2 佔11.1 % ，本群病原性較弱，主要危害莖部；TRAG 3 及TRAG 4 各佔39.9 與38.9 % ，均可分另別由莖、莖基部及種薯侵入為害。 Potato cultivars, such as Wu-feng and Ko-nan, were susceptible to black scurf caused by Rhizoctonia solani Kűhn. A survey carried out in the 1977/1978 period indicated that there were 31.2 ± 3.2% and 52.7±7% of disease for the variety Wu-feng at the late growth period and the time prior to harvest, respectively. While there were 16. 4±3.7% of disease for the variety Ko-nan at the time prior to harvest. Of those diseased potatoes, about 9.3% were caused by isolates of anastomosis group 1 (TRAG 1) which infected stems and eventually extended to stem bases and tubers, about 11.1% were incited by isolates of anastomosis group 2 ( TRAG 2) which showed weeker pathogenicity and were only able to infect stems, and about 39.8 and 38.9% were incited by isolates of anastomosis groups 3 and 4 (TRAG 3 and 4), respectively. Both TRAG 3 and TRAG 4 could infect stems, stem bases and tubers.