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Sensitivity of Chinese Isolates of Plasmopara viticola to Metalaxyl and Dimethomorph
Author(s) -
Sun Haiyan,
Wang Hancheng,
Stammler Gerd,
Ma Jianxia,
Liu Jianmei,
Zhou Mingguo
Publication year - 2010
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.2009.01633.x
Subject(s) - metalaxyl , plasmopara viticola , biology , fungicide , ec50 , downy mildew , phycomycetes , botany , horticulture , inoculation , in vitro , biochemistry
During 2007 and 2008, 392 isolates of Plasmopara viticola were collected from 11 regions in seven provinces in China, and their sensitivities to metalaxyl and dimethomorph were determined by the floating leaf disk technique. Among all isolates, 13% were classified as sensitive, 26% as low‐level resistant, and 61% as resistant to metalaxyl. Of the 392, 85 were from vineyards never treated with carboxylic acid amide fungicides; these isolates were used to determine the baseline sensitivity to dimethomorph, and their EC 50 values ranged from 0.01 to 0.21 (mean ± SD, 0.11 ± 0.04) μg/ml. The other 307 isolates were completely inhibited by a single discriminatory dose of 1.6 μg/ml of dimethomorph.