Adult lace bugs are typically 1/10th of an inch long and cream-colored. They have lacy wings dotted with black and brown patches or bands. The eggs are 0.02 in long and usually laid on the midrib or leaf margins of young leaves; they are covered with a dark brown adhesive material that forms a hard protective covering. Nymphs are black and spiny and are often found feeding gregariously.

Figure 1. Azalea Lace bug. Brian Kunkel, University of Delaware.

Habitat

This group of pests can be found feeding on azalea, cotoneaster, hawthorne, oak, rhododendron, and sycamore among others. They feed on the underside of leaves throughout the mid-Atlantic and southeast.

Life Cycle

Eggs are usually found partially embedded along veins on the underside of leaves. Dark-colored nymphs hatch in about two weeks (1st gen. azalea lace bug nymphs active, 240 - 561 [318 peak] GDD50), and they have five instars before becoming adults. Twenty-two to 45 days are needed to grow from egg to adult, and this development is influenced by temperature. We may have two to four generations per year.

Figure 2. Lace bug nymph. Tracy Wootten, University of Delaware.

Damage

Lace bugs cause bronzed or bleached-out leaves due to sucking out leaf cell contents. They also excrete excrement out onto the leaves that appear as small, black spots called tar spots.

Figure 3: Azalea Lace Bug damage. Brian Kunkel, University of Delaware.

Figure 4. Lace bugs and tar spots. Brian Kunkel, University of Delaware.

Treatment

Cultural control. Some lace bugs can be managed by planting the host plants in locations favorable for the plant to grow. For example, rhododendrons or azaleas in partial shade and acidic soils are favorable for the plant and reduce the likelihood lace bugs will become problematic. The health of oaks and sycamores are rarely threatened by lace bug populations.

Biological control. A number of insects will feed on lace bugs, such as lady beetles, assassin bugs and lacewings. Small wasps also attack lace bugs and are called parasitoids. These wasps develop inside their lace bug hosts. Predatory mites and spiders may also eat this pest.

Chemical control. A variety of insecticides are available for control of lace bugs; however, many times lace bug populations can be managed with either cultural practices or biological control. If an insecticide is desired; then, reduced risk products such as insecticidal soaps or horticultural oils should be applied to the underside of the leaves. These products require direct contact with the pest to be effective. These have less impact on the beneficial arthropods we need in our landscapes. If other products are desired; then contact the nearest local cooperative extension office for recommendations.

Download/Print PDF Version

UD Cooperative Extension

This institution is an equal opportunity provider.

In accordance with Federal law and U.S. Department of Agriculture policy, Cooperative Extension is prohibited from discriminating on the basis of race, color, national origin, sex, age, or disability.