powdery mildew close-up on burlap

leaf nature green tree plant soil rock flower grass wildlife insect branch trunk autumn wood invertebrate geology powdery mildew close hessian burlap close-up fungal fungi disease spores erysiphales pathogen humidity fungicide common visible detail macro natural biology botanical danger damage gardening greenhouse harmful infest spoilt crop nuisance destructive foliage spread infect watering wet conditions squash problem close- infected leaves