Susceptibility level of cucumber downy mildew (Pseudoperonospora cubensis) to metalaxyl

Level of susceptibility of Pseudoperonospora cubensis isolate from Ratkovo to metalaxyl in concentrations 50, 100, 200, 400 and 800 ?g/ml was investigated. The trials were conducted on cotyledon and fully developed young leaves using cucumber cultivar Haros. Reduced level of susceptibility was detected in metalaxyl concentrations of 50, 100 and 200 ?g/ml because the intensity of sporulation in these treatments was on the same level as in control. Sporulation was also observed on developed leaves treated with metalaxyl in concentrations of 400 and 800 ?g/ml.