BioBudsanswered grow question 4 years ago It look likes mildew: several solutions: lower humidity, defoliate, ventilate, dont let leaves/ buds / stems touch. One can spray lightly with several solutions on the market or hydrogen peroxyde or more organically with neem oil, a nettle fermented tea, or a tea made from horsetail. But fix humidity and foliage first. dont touch leaves after touching patchy bits. Contagious.