First Report of Powdery Mildew of Periwinkle Caused by <i>Golovinomyces orontii</i> in North America

Fig. 2. Golovinomyces orontii appressorium formed on Vinca major. Scale bar = 15 mm.



Image from Plant Health Progress article:
First Report of Powdery Mildew of Periwinkle Caused by Golovinomyces orontii in North America