Lace bugs are a problem on azaleas each year in Louisiana. These little pests are now beginning to emerge from the eggs laid this past year.
Azaleas that receive radiated heat from nearby buildings are the first to show injury.
Four species of lace bugs feed on azaleas and rhododendrons, says LSU AgCenter entomologist Dennis Ring. The azalea lace bug, Stephanitis pyrioides, is the most damaging. Another species of lace bug infests lantanas in Louisiana, but their damage is more common in summer and fall.
Injury symptoms on infested plants include bleached, stippled, silvery or yellowed leaf areas. The greatest concern is aesthetic.
The lace bug lays eggs in groups partially embedded in the undersides of leaves. Females lay five to seven eggs per day and about 300 eggs during their life. Eggs develop in 12 to 22 days, depending on temperature. After they emerge, nymphs feed in small clusters, and in 10 to 23 days develop into adults that live from one to four months. There are two to four generations per year.
Both nymphs and adults cause damage by piercing the leaf tissue and sucking out the contents, Ring says. They remove chlorophyll near the upper surface of the leaf, causing areas that are bleached, stippled, silvery or yellowed.
Damaged leaves will look bad all season if they’re not severely damaged and fall off.
The adult lace bug is about 1⁄10-inch long and cream-colored, Ring says. The wings are longer than the body with black or brown patches and are netted and lacy in appearance. They are easy to overlook because of the transparent wings and small size.
To examine plants for lace bugs, knock the leaves against a piece of white paper. If they are present, lace bugs will fall on the paper and be easily seen.
If you find the bugs, you can use several materials to manage them. The insecticides acephate, malathion, Bayer Advanced Garden with imidaclorpid, summer horticultural oil and spinosad are all effective for managing this pest.
Got a gardening question? Write to GardenNews@agcenter.lsu.edu.