Azalea lace bugs were first documented in Oregon in 2009, but they were not a huge problem until 2012-13. Lace bugs are now very widespread and most everyone who owns azaleas in Portland (some rhododendrons are affected too) has a lace bug problem. Because of this, azaleas can no longer be considered carefree, inexpensive plants.
Lace bugs suck chlorophyll out of leaves, impairing the plant’s ability to make nutrients from sunlight. Damage from adult azalea lace bugs makes leaves look stippled with yellow or white on top and black or brown spots (bug poo) on the underside of leaves.
Begin treatment when nymphs are visible. Start looking for them in early May on the undersides of leaves. Nymphs are up to 1⁄4” long and translucent with bits of yellow-green. If you’re having trouble seeing them, hold leaves up to a light and look for nymph shadows.
Insecticides will help control lace bugs, but may also harm beneficial insects and bees. Apply only to non-blooming plants, in early morning or evening when bees are not present.
Listed from least toxic to beneficial insects, bees, pets, and humans to most toxic:
OSU on Azalea Lace Bugs
How Colony Collapse Disorder Works
Lace bugs are fairly new in the Pacific Northwest so local research on the subject is new and ongoing. Azalea lace bug has been present on the East Coast for longer, and research has been done to find resistant varieties.
If you are considering planting azaleas in your yard, selecting plants from these lists may save you a headache later. Keep in mind, “bug-resistant” does not equal “bug-proof,” but these varieties should fare better.
The Best Practices approach, sometimes called Integrated Pest Management (IPM) is an environmentally sensitive approach to dealing with garden pests. Printable pdfs can be found on each page.