I have 7 PJM rhododendrons planted along the east side of my house in NE Portland. This summer I identified lace bug too late for the spring drench. They have been sprayed by me twice and twice by com Erica, sprayer. They now look as I’d they have a fungus. Portland nursery looked at some branches as did Master Gardeners (via internet). Both really did ‘t Know what was wrong. Does your website have pictures of possible Rhodie diseases? I can’t find any .
Multnomah County Oregon rhododendron
Thank you for your question. This diagnostic handbook lists diseases that are known to occur here on rhododendrons and azaleas: https://pnwhandbooks.org/plantdisease/host-and-disease-descriptions?title=rhododendron You can go through them and compare your plants’ symptoms, although you may need to go to a different web page for photos: https://pnwhandbooks.org/plantdisease/host-and-disease-descriptions?title=rhododendron You can also submit a sample to the OSU Plant Clinic for ID: https://bpp.oregonstate.edu/plant-clinic Good luck!