Key Features
- Leaf discoloration
- Black fecal pellets
- Small, lacy-winged bugs
Symptoms
Lacebugs injure leaves and suck out green liquid from leaf undersides and leave behind white spots. The accumulation of white feeding spots on leaves can give them a bleached white appearance or cause them to drop prematurely. Lacebugs leave black spots or tar-like excrement on leaves as they feed. Black oval eggs laid into the leaf tissue are visible to the naked eye. Adults have clear, lace-like flat wings. The immature stages (nymphs) are black and spiny. Though damage may superficially resemble spider mites, no webs are present on leaf undersides.
Biology
Many lacebug species are restricted to a single kind of plant. They have from 1 to 3 generations a year depending on species and temperature. Species life cycles fall into two categories. Lacebugs that feed on evergreen hosts such azalea and rhododendron winter as eggs in leaf tissue. Lacebugs that feed on deciduous hosts winter as adults in bark crevices and other sheltered areas. They emerge in spring soon after leaves break bud. Eggs are laid into leaf tissue and appear to be leathery and black. Spiny immature lacebugs (nymphs) take about 30 days to become adults.
Management Recommendations
Lacebugs tend to be problematic in open sunny areas where natural enemies lack the resources they need to keep the pest from becoming a problem. Lacebugs can be controlled through foliar sprays directed against immature stages. Look for spiny immature lacebugs (nymphs) near egg masses on leaf undersides. Use a hand lens to determine when eggs have hatched. The use of selective products like chloantraniliprol, neem, oil and soap, can kill nymphs to conserve natural enemies. Other products like imidacloprid and dinotefuran will kill lacebugs, but are not recommended because they may cause spider mite outbreaks later in the season, and negatively impact pollinators.
Effective Pesticides
Active Ingredients include: Acephate, Azadirachtin, Bifenthrin, Chlorantraniliprole, Cyantraniliprole, Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid), Lambda- cyhalothrin, Permethrin
Resources
