Metalaxyl-Resistant Strains of Pseudoperonospora cubensis in Cucumber Greenhouses of Southern Greece. S. G. Georgopoulos, Laboratory of Plant Pathology, Athens College of Agricultural Sciences, Votanikos, Athens 301, Greece. A. C. Grigoriu, Laboratory of Plant Pathology, Athens College of Agricultural Sciences, Votanikos, Athens 301, Greece. Plant Dis. 65:729-731. Accepted for publication 20 December 1980. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-729.

No systemic or translaminar activity of metalaxyl against three strains of Pseudoperonospora cubensis could be demonstrated in artificially inoculated cucumber leaves, although the fungicide concentrations were several times higher than recommended. Some protective action was noticed but was unsatisfactory compared to that of a standard protectant. The strains appear to possess stable metalaxyl resistance.