A Decade of Hop Powdery Mildew in the Pacific Northwest

Fig. 2. Healthy hop cones (A, shown here), and cones with reddish-brown discoloration caused by powdery mildew (B and C). Mycelia of the fungus is visible on the cone in C.



Image from Plant Health Progress article:
A Decade of Hop Powdery Mildew in the Pacific Northwest