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Rhododendron Pathogen #922756

Asked December 09, 2025, 12:17 AM EST

Hi, I recently had a client ask me about a white spots on his leaves (see pictures) and I was wondering if this might be microsphaera or some other identifiable pathogen? In any case is this something that needs to be/can be treated? Thanks

Benton County Oregon

Expert Response

That's a bad infestation of azalea lace bug. Look on the undersides of the leaves and you will see black spots of frass and over-wintering eggs. Yes, it needs treating, it will only get worse if you don't. Here's a link to the azalea lace bug page on SolvePestProblems, a site you may want to bookmark. We are still building it out, but it has good information on dealing with many garden pests and diseases.
https://solvepestproblems.oregonstate.edu/plant-problems/azalea-rhododendron/lace-bugs
Signe Danler, Online Home Horticulture Instructor Replied December 10, 2025, 2:29 PM EST

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