In green house trial, all tested cucumber cultivars were differed in their response to downy mildew disease Beto Star cultivar exhibited the highest percentage of infection (74.84%) and considered the highest susceptible genotype tested, while Shourk cv. was the least susceptible one (33.71%). All commercial biocides applicator as protected treatment reduced downy mildew disease severity in both Tokh and Sakha locations. Rhizo-N resulted in the highest efficacy in controlling the downy mildew disease (62.65 and 61.17%), while Plant Guard was the lowest  in this respect, in comparison with Shampion fungicide . In addition, all bioagent treatments, which reduced downy mildew infection significantly improved the plant growth and increased the plant height, the number of flowers and fruit yield, when  they were sprayed as protected treatments. Rizo-N exhibited the best effective one , where it resulted increasing in plant height, number of flowers and fruit yield( 286cm/ plant , 91.90/plant and 49.94 kg/polt), respectively followed by Shampion fungicide and Blight Stop ,while Plant Guard was the least effective one . The curated commercial biocides treatment showed the lowest efficacy in controlling the downy mildew disease and plant growth parameters compared with Equagen Pro fungicide resulted in the highest efficacy in controlling the disease and increased plant height, number of flowers and yield at Tokh and Sakha, respectively. Infected cucumber leaves exhibited more activity of oxidative enzymes than healthy in both treatments of biocides as protected or curetted. On the other hand ,activity of the determined enzymes were decreased when Equagen Pro fungicide was used curetted treatment compared  to the other biocides .