Chitosan has also been extensively utilized as a foliar treatment to control the growth, spread and development of many diseases involving viruses, bacteria, fungi and pests [20]. It has also been used to increase yield and tuber quality of micropropagated greenhouse-grown potatoes [56]. Similarly, Faoro et al. [57] showed that the use of chitosan applied as a foliar spray on barley reduced locally and systemically the infection by powdery mildew pathogen Blumeria graminis f. sp. hordei.