1978年静岡県のイチゴ品種麗紅,宝交早生に萎ちょう,枯死する株の発生が認められた。発病株はクラウン,葉柄基部およびクラウンに接続する根が褐変枯死し,罹病組織からPhytophthora属菌が分離された。分離菌株の形態的特徴,生育温度,電気泳動パターン,接種試験の結果,本菌はPhytophthora nicotianae var. parasiticaと同定された。分離菌225株は全てmating type A2であった。本病は本邦で未報告の病害であるのでイチゴ疫病としたい。
Verticillium dahliae Klebahn was isolated from various crops in Hokkaido. Most of the Verticillium isolates that had previously been identified as V. albo-atrum Reinke and Berth. or Verticillium sp. by other workers were also reidentified as V. dahliae Klebahn due to presence of microsclerotia, wide host range, possibility of growth at 30 C, and hyaline basal cells of conidiophore.
Verticillium dahliae was found to be the cause of Verticillium black-spot disease of radish (Raphanus sativus L.), which has not been described up to this time. Diseased plants exhibited black discoloration of the xylem of the tap root and inconspicuous yellowing of the lower leaves. Inoculation experiments indicated that the fungus was also pathogenic to turnip, egg-plant, strawberry, tomato and cucumber.