NC State Extension Publications

Description and Biology

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Sycamore lace bugs are small (about 1/8 inch long), white or whitish with a black spot on each wing and on the thorax. This bug is almost rectangular in outline. The sides of the thorax and wings are flattened and covered with veins that give the bug a lacy appearance. Nymphs are smaller, black and spiny. Females emerge in spring and fly to sycamores to lay eggs on the underside of leaves along the leaf veins. Each female can lay up to 350 eggs. Newly hatched nymphs stay close together for the first three molts. After the fourth molt, nymphs may mover to new leaves. New adults emerge after the fifth molt. A typical life cycle takes six to eight weeks. Several generations per year occur in the South. Sycamore lace bugs overwinter as adults, either under loose bark of the trees, or in nearby cracks and crevices. Adult sycamore lace bugs are very mobile, are good fliers, and may migrate for a considerable distance when supported by the wind.

Sycamore lace bug

Sycamore lace bugs are whitish with dark spots.

Sycamore lace bugs

Sycamore lace bugs sometimes occur in dense groups.

Sycamore lace bug nymphs

Sycamore lace bug nymphs are small, black, and spiny.

Host Plant

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Sycamore is the primary host plant of the sycamore lace bug in North Carolina although paper mulberry, shagbark hickory, leatherleaf, and ash trees have also been reported. Sycamore lace bugs feed on the lower leaf surface and cause yellow or pale spots to appear on the upper leaf surface. If much feeding occurs, the leaves may become almost bleached out and may fall prematurely. Lace bugs also leave "fly specks" or excrement on the lower leaf surface.

Residential Recommendations

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Sycamore lace bugs are relatively difficult to control especially if the tree is large. The population may resurge later in the season, because of eggs not killed by the first treatment. Later in the growing season, it may be just as well to wait until the next year to treat. Even if every last lace bug is eliminated, the damaged leaves will not improve in appearance. Insecticides can be applied as foliar sprays, trunk injections, and even soil treatments, but these are costly, and efficacy is often marginal because of re-invasion from nearby trees. Most of the time, treating sycamores is unnecessary and unwarranted. Despite the visual impact of severe damage, the impact on tree health by occasional defoliation on otherwise healthy sycamore is minimal.

References

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology

Publication date: July 18, 2016
Revised: Oct. 15, 2019

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