Eficacy of Trichoderma harzianum, T. hamatum, T. viride, and Chaetomium sp. as foliar spray against purple blotch of onion (Allium cepa) was evaluated. The fungicides Blight stop (bio) and Luna Experience SC (chemical) at certain doses were used as a check. All treatments recorded the highest efficacy percentage for reducing severity of purple blotch compared to control, where it gave 88.85 and 69.76% after four and seven sprays respectively. Trichoderma
harzianum was the superior treatment more than Blight stop as a check. On the other hand, Chaetomium sp. showed the lowest effect. Also, all treatments increased onion yield, plant height, number of leaves and fresh weight/plant, total carbohydrates, total nitrogen an dtotal soluble solids as compared to non-treated plants.