Field experiments were carried out under natural infection of basil downy mildew in the Experimental Farm of Sids Agricultural Research Station, Agric. Res. Center, Beni-Sweif governorate during 2015 and 2016 growing seasons in order to evaluate the efficacy of different compounds of resistance inducers, mineral salts and antitranspirants applied on sweet basil plants (Balady variety) as foliar spray combined with two rates of nitrogen fertilizer for controlling basil downy mildew caused by Peronospora belbahrii. In general, all treatments had a positive effect on the reduction of disease severity with significant increase in fresh and dry weights of herb and essential oil yield at the end of experiment. The high efficacies of the tested compounds were observed when nitrogen was applied at the recommended rate. Chitosan (0.05 %), di-potassium phosphate (20 mM) and potassium silicate (20 mM) in addition to the fungicide Stone 50 % were the most effective in this concern. Furthermore, plants sprayed with each of chitosan, di-potassium phosphate and potassium silicate showed significant increases in the defence-related enzymes, peroxidase (POD) and phenylalanine ammonia-lyase (PAL) as compared with the untreated basil plants