The effects of essential oils of clove and fennel seeds and their major components as foliar spray were screened for inducing resistance against Potato Virus Y in vivo in both systemic and local lesion hosts at different concentrations. Clove oil at conc. of 15% gave the highest inhibitory effect against PVY infection than fennel oil. The inhibition percentages were 85, 80 % in pepper as a systemic host and up to 90, 87 %, respectively in Chenopodium amaranticolor as a local lesion host when applied 48 hrs before virus inoculation. Whereas, the inhibitory effect was less pronounced when essential oils were sprayed on the tested plants 24 hrs before virus inoculation. However, the severity of symptoms was assessed by visual inspection. ELISA test was used to confirm the results in all cases. When the major components of essential oils were applied individually, Eugenol gave the highest inhibitory effect (90%) on PVY- systemically infected pepper plants and 91.8% on Ch. amaranticolor as local infected plants when applied 48 hrs before virus inoculation followed by Anethol. While, Limonene was less effective in reduce PVY infection. Considerable increase in total protein content in pepper plants sprayed with essential oils and their major components before virus inoculation was recorded compared with healthy and infected control plants. Moreover, SDS-PAGE revealed a new protein band 20 KDa which was found only in pepper plants sprayed with clove oil at conc. of 15%. Also new proteins 19, 20 KDa and 25 KDa were found only in pepper plants sprayed with Eugenol. It has been suggested that, the induced proteins may help to limit virus spread or multiplication.