Under greenhouse and artificial soil infestation conditions, application of Plant Guard (5 ml/l), Clean roots (4 g/l), Root Most (10 ml/l) and Multi VAM (50 ml/l) reduced the incidence of white rot disease of onion (cv. Giza 20) than the control free treatment. Under field and natural soil infestation conditions, disease reduction was also higher than the control treatment when Root Most, Multi VAM, Plant Guard, Clean roots and Alga 600 were applied, individually at 2009/10 season. Folicur fungicide (20 ml/l) reduced the disease incidence by 72.6%. Yield production was responded positively to the commercial compounds application. Root Most and Multi VAM recorded the highest yield production in both 2009/10 and 2010/11 growing seasons. They were more effective for yield increments than Folicur. Activity of peroxidase and catalase enzymes in onion plant tissues were highly increased in response to different treatments application. On the other hand, polyphenol oxidase activity was severely decreased than control, as a result of various compound applications. The total phenolic compounds were increased in onion tissues of the plants treated with each of the tested compounds.