Abstract
Sensitivity of Corynespora cassicola, causal agent of Corynespora leaf spot of cucumber, isolated from cucumber plants in Okayama Prefecture to thiophanate-methyl (T) and diethofencarb (D), and azoxystrobin (A) was investigated using the minimum inhibitory concentration (MIC) method and a bioassay. With the MIC method, 29 isolates among 193 isolates were highly resistant to both T and D. In the bioassay test, an isolate resistant to A was isolated from cucumber plants in a field. This report is the first on isolates of the causal fungus that are highly resistant to both T and D and the second report on isolates resistant to A.
