Garden Column for Concord Independent/Tribune
Darrell Blackwelder
July 29, 2003

    Many have called complaining that the foliage of their azaleas and rhododendron are turning yellow and splotchy. The problem is caused by lacebugs, a small, clearwinged insect that usually appears in the spring and again in late summer. The foliage has small yellow splotches at first, and then turns completely yellow after a massive infestation. Premature leaf drop occurs when plants are heavily infested.
    Both immature and adult lace bugs are found most often on the underside of leaves. Spots of excrement resembling dark varnish appear, mostly on the underside of the leaves.
Female lace bugs lay groups of eggs on the underside of leaves, most often along the midrib. These eggs are dark colored and are partially inserted into the leaf tissue or are pale and completely hidden inside the leaf. Dark, spiny nymphs hatch from the eggs.
    Adult lace bugs have lace-like wings and an expanded, lacy hood back of the head. Several different species of lace bugs are found in North Carolina and most of them produce two or more generations in a year. Adults are about 1/8 inch long and 1/16 inch wide. This insect usually spends the winter in the egg stage.
    Repeated applications of Orthene, Sevin, Malathion or an insecticidal soap are registered pesticides that effectively control lace bugs. Make the first application as soon as nymphs appear on the undersides of the leaves. Follow with a second application 7 to 10 days later if needed. Repeat as needed at monthly intervals.
    Thorough coverage is essential when applying sprays if good control is expected. It is very important to be sure the underside of the leaves is covered. Use high pressure to make sure the underneath of the leaves are covered. Simply spraying over the top of the plant will not control the pest.
    As with any pesticide, always read and carefully follow the instructions. Contact the Cooperative Extension Service at 704-633-0571 if you have questions about application or use of any pesticide.

Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. For archived garden columns or other information, visit the Rowan County Master Gardener web site at www.rowanmastergardener.com , e-mail Darrell_Blackwelder@ncsu.edu or phone at 704-633-0571.