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There are several species of lace bug that infest ornamental shrubs & trees in our area. While often found “in the wild”, their damage is minimal and they are well controlled by natural predators, in the landscape their numbers can become damaging on their favored host plants. Lace bug damage is common on azaleas, Japanese andromeda, mountain laurel, rhododendron, cotoneaster, Indian hawthorn and pyracantha.
Damage consists of tiny white speckles that indicate feeding damage. This damage can become so dense that the speckles coalesce, giving a bleached-out appearance to the leaves. Once damaged, leaves do not recover.
Along with the feeding marks, the presence of dark, shiny specks of fecal matter on the underside of the leaves is indicative of lace bug. The bugs themselves are small with lacy, semi-transparent wings and can be difficult to see. You may see glints moving around the leaf as light is reflected from their shiny wings.
Non-chemical controls begin with proper plant selection and location. It has been noted that mixed plantings are less affected by lace bug than mass plantings of the same plant. Plants stressed by drought or excessive sun exposure tend to be more affected. To minimize lace bug damage, plant in mixed groupings if possible and do not exceed plant's preferred sun exposure.
Systemic pesticides or horticultural soaps or oils which have reduced risk to beneficial insects are preferred, as a healthy population of predator insects can greatly help in keeping lace bugs under control. Systemic pesticides can be applied in spring, and reapplied if needed as the product directs. Begin applying non-systemic spray pesticides as crawlers are seen in spring, and repeat at 7-10 day intervals, or as your chosen pesticide directs. For pesticide sprays, a thorough coating of the underside of the leaf is important to contact the insects. Eggs can also be smothered in winter with dormant oil sprays.
**Always read and follow label directions for all pesticides.**