Birch Lace Bug: Appearance, Territory, Damage, and Life Cycle

Latin Name: Corythucha Pallipes

Appearance: Lace bugs may be identified by the mottled appearance of the leaves, as well as the presence of the insects and the typical black fecal marking on the undersides of the leaves. Adult insects are easily identified by their fully formed wings, which are quite wide, flattened, and densely veined, giving them a lace-like appearance. Color patterns on the bodies of different species vary, and the wingless nymphs are equipped with spines around the perimeter of their bodies. They are tiny insects that are just around 1/8 inch long. This species features noticeable black bars on the front and back of the wings, as well as on the thorax.

Hosts Plants: Yellow and white birch, beech, maple, willow, and mountain ash.

Territory: North America

Damage Insect Cause: Lace insect infestations seldom cause any plant harm, aside from the unpleasant appearance of the leaves from the feeding and fecal stains. Leaves that have been heavily affected become brown and fall off. Most pesticides are effective when sprayed, but they must be administered extensively to the bottom surfaces of the leaves. Lace bugs are efficiently controlled by horticultural oils, safer soaps, neem oil, and conventional residual pesticides. Because the eggs may be tucked into plant tissues, they are resistant to pesticides, and numerous treatments may be required.

Life History and Habits: Every year, there are two generations. Winter is spent as an adult in leaf litter. Eggs are placed in clusters of 4-10 on the bottom surfaces of leaves in the axils of veins in the spring. Dark brown nymphs molt five times before reaching maturity. Adults have lacelike forewings and are about 4 mm long.

In colder climates, the bugs will hibernate during the winter as adults buried behind bark fissures or in heaps of fallen leaves, or as eggs placed within the tissues of evergreen tree leaves. In the spring, the eggs hatch, and the emerging nymphs go through various phases before becoming winged adults. Each year, many generations can be predicted. They feed by inserting a proboscis into the leaves and sucking fluids out. Extensive feeding causes chlorosis and a mottled or stippled appearance to the leaves, as well as massive accumulations of black fecal droplets.