Azalea lace bugs are the most common insect pest of azaleas. Most azaleas harbor some lace bugs and light infestations cause no real harm, but when present in high numbers, azalea lace bugs are a major problem, causing leaves to be bleached or bronzed and causing plants to grow and bloom poorly. Both adults and immatures (nymphs) cause damage by sucking sap from the undersides of leaves.
Heavy, damaging infestations of lace bugs are most likely to occur on azaleas growing in full sun or on plants that are stressed by drought or other factors. Also, some varieties are more susceptible than others. Once plants are severely damaged, it can take some time for them to recover.
Avoid excessive lace bug damage to azaleas in your landscape by making it a point to regularly check the undersides of leaves for adults or nymphs. You won’t be able to find these through the winter months, because lace bugs overwinter as eggs inserted into the leaf tissue, although the brown fecal spots left from the previous growing season will remain on the undersides of leaves as a sign of infestation. Begin scouting in early spring and consider treating if you start finding significant numbers of lace bugs and damage symptoms. Also, some plantings have a history of recurring lace bug infestations, and these are candidates for early preventive treatments. Soil-applied systemic insecticides usually provide season-long control, and, although somewhat costly, these are a good choice for treating plantings that routinely suffer heavy attack.
Control: For fast-acting control of heavy lace bug infestations spray with a foliar applied systemic insecticide such as acephate (Bonide Systemic Insect Control) or imidacloprid + cyfluthrin (BioAdvanced Complete Insect Killer). For long-lasting preventive control use a soil-applied systemic treatment such as imidacloprid (BioAdvanced Tree and Shrub Insect Control). For best control of severe infestations do both; spray with acephate and apply a soil treatment of imidacloprid. Be sure to follow label precautions for protecting pollinators.
See Extension Publication 2369, Insect Pests of Ornamental Plants in the Home Landscape, page 17-18 and pages 38-40 for more information. http://extension.msstate.edu/sites/default/files/publications/publications/p2369.pdf
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
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