Azalea Lace bug
I have reviewed the fact sheets on azalea lace bug and am wondering, if the plants are not treated, what the long-term impact on mature landscape rhododendrons is expected to be? I understand that this insect harms the plants (and makes them unsightly) but it is unclear if their feeding will ultimately result in the decline and death of landscape rhododendron plants? Also just curious if this insect pest is a big problem for the native wild rhodendrons that grow hereabouts?
Multnomah County Oregon
Thank you for your question. The feeding of the nymphs deprives the plant of food (through photosynthesis), and, if left unchecked, can result in the decline of the plant, leaving it leafless and/or susceptible to infections and other insect infestations. . It is less common on rhododendron plants, perhaps because their leaves have a thicker coating, making the bugs' stylets less effective. However, a rhododendron leaf bug has been found in the East, but they have fewer rhododendron plants than do we here in the Pacific Northwest.
Here is are a couple of articles on them that you may already have found: http://oregonstate.edu/dept/nurspest/Azalea_lacebug.pdf
It may also be that native forests have other factors present to curtain these bugs' impact: "Lace bugs. Azalea lace bug, Staphanitis pyroides, feeds on azalea and rhododendron and causes the leaves to become discolored with white stipples. With up to four generations a year, entire plants can appear as if the leaves were bleached. In nature these plants are found in the forest understory. Studies conducted in Maryland indicate that outbreaks were most common when azaleas were isolated, or the landscape was sparseley planted. In more complex habitats, where flowers were present, and plants were shaded by tall trees, natural enemies were more abundant and lace bug problems were far less numerous. Lace bugs also grew from egg to adult more slowly in these shaded sites." (http://www.entomology.wisc.edu/mbcn/fea512.html)
I hope this is helpful to you.