Powdery mildew
underside of the leaf. On the upper side, yellow spots are noticeable. In case of a severe epidemic, the fluffy colonies also appear on the upper side of the [...] and makes it harder for the fungi to enter the leaves To reduce chances of powdery mildew in greenhouses, it is advised to first ventilate by only opening [...] extremely sensitive to water and ‘hides’ on the underside of the leaves. Therefore, this is where the colonies mostly occur in these crops. In covered roses