Differentiating Powdery Mildew from False Powdery Mildew

Abstract

ABSTRACT This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring color illustrations of signs and symptoms. The fungus Trichothecium roseum produces a white fuzz that covers branches, leaves, and flowering tops of hemp. These symptoms have been confused with true powdery mildew, caused by Sphaerotheca macularis. We illustrate the differences between disease caused by Trichothecium roseum (henceforth dubbed “false powdery mildew”) and disease caused by Sphaerotheca macularis.