Lace Bug Feeding Injury Appearing

Lace bugs use their sucking mouthparts to feed on plant sap. Damage ranges from a few scattered tiny white-to-yellow spots on upper surfaces of leaves to bleached-white leaves that drop prematurely in late summer (Figure 1). Common species in Kentucky feed on azalea (azalea lace bug); hawthorn, cotoneaster, pyracantha, Japanese quince (hawthorn lace bug); rhododendron and mountain laurel  (rhododendron lace bug); and hickory, mulberry, and sycamore (sycamore lace bug).

Figure 1. Lace bug damage is evident on upper surfaces of the lightened leaves, while the darker green leaves do not show damage. (Photo: Paul Bachi, UK).

Figure 1. Lace bug damage is evident on upper surfaces of the lightened leaves, while the darker green leaves do not show damage. (Photo: Paul Bachi, UK).

Confirm Lace Bug Damage

Lace bugs can be confirmed as culprits by looking at undersides of spotted leaves for the insects, white cast skins, tarry waste spots, or eggs (larger dark spots along leaf midribs) (Figure 2). Adults are about 1/8 inch long with lace-like wings that cover the abdomen. Nymphs are dark and spiny (Figure 3).

Figure 2. Check lower leaf surfaces for evidence of lace bug insects, black tarry waste spots, and regular rows of dark eggs. (Photo:Paul Bachi, UK).

Figure 2. Check lower leaf surfaces for evidence of lace bug insects, black tarry waste spots, and regular rows of dark eggs. (Photo:Paul Bachi, UK).

Figure 3. Close-up of a spiny lace wing nymph, along with flat, tarry fecal spots, and cylindrical eggs present on lower leaf surface (Photo: Brenda Kennedy, UK)

Figure 3. Close-up of a spiny lace wing nymph, along with flat, tarry fecal spots, and cylindrical eggs present on lower leaf surface (Photo: Brenda Kennedy, UK)

 

Management

Heavily-infested leaves may drop prematurely.  However, late season leaf loss should not affect healthy trees, so no control is needed.

 

By Lee Townsend, Extension Entomologist

 

Posted in Landscape Trees & Shrubs