Four bioagents, i.e. Bacillus megaterium, B. pumilus, B. subtilis and B. thuringiensis, and four resistance inducers (RI), i.e. chitosan, humic acid, potassium monophosphate and salicylic acid as well as cow full cream, skim and milk whey caused significant reduction in the germinated conidia of Golovinomyces cichoracearum var. cichoracearum (D.C.) Heluta (syn. Erysiphe cichoracearum D.C.), the causal of cucumber powdery mildew compared to the check treatment. This reduction was increased with increasing the tested concentration. In greenhouse experiment, spraying the tested bioagents and RI as well as cow full cream, skim and whey milk resulted in different decrements in the disease severity and increments in plant length as well as foliage fresh and dry weight. Field experiments during 2013 and 2014 growing seasons revealed that spraying of B. subtilis, potassium monophosphate and cow whey milk, individually or in combinations, caused significant reduction in the disease severity with significant increase in the fruit yield. Spraying these compounds individually was less efficient in this regard compared with spraying them in combinations. Combination of B. subtilis + potassium monophosphate + cow whey milk recorded more disease reduction and yield increase. Therefore, the reference fungicide was mostly efficient as the combined treatment.