Cause The fungus Golovinomyces sp. (possible G. oronii or G. vincae) was found on Vinca minor plants in western Oregon in 2019. Disease distribution was on leaves of landscape plants under eves of a home. Plants in the open or under cedar trees were not obviously infected.
Symptoms Thin, white to gray mycelial mats or colonies were seen on both leaf surfaces.
Cultural control
- Remove and destroy infected plants or plant parts.
Chemical control
- Pageant at 12 to 18 oz/100 gal water. Do not use with organosilicone-based adjuvants. Group 7 + 11 fungicide. 12-hr reentry.
- Seido at 4 to 5 fl oz/100 gal water plus an adjuvant. Group 50 fungicide. 4-hr reentry.
- Terraguard SC at 4 to 8 fl oz/100 gal water. Group 3 fungicide. 12-hr reentry.