Sycamore Tussock Moth (Halysidota harrissi Walsh)
Leininger, T.D; Solomon, J.D.; Wilson, A. Dan; Schiff, N.M. 1999. A Guide to Major Insects, Diseases, Air Pollution Injury, and Chemical Injury of Sycamore. Gen. Tech. Rep. SRS-28. Asheville, NC: USDA Forest Service, Southern Research Station. 44 p.
This insect feeds on sycamore leaves throughout the Eastern United States. It is more likely to defoliate older plantations, seed orchards, and ornamental plantings than nurseries and young plantations. Repeated late-summer defoliation reduces growth and vigor.
Identifying the Insect
Larvae have orangish heads and yellowish bodies covered with hair. Caterpillars (30 mm long) exhibit long hair pencils-two pairs of orange and 2 pairs of white hair pencils anteriorly, and one pair of white hair pencils posteriorly. Moths are pale yellow with darker bands on forewings.
Identifying the Injury
Young larvae skeletonize the leaves, feeding together on the leaf’s underside. Older larvae devour all but the major leaf veins.
Moths emerge from overwintering cocoons during May and June and deposit egg masses on the underside of leaves and on bark. Eggs hatch in late May and June. Young larvae feed close together; older larvae scatter and become solitary feeders. Pupation occurs in late June and July in hairy, ball-like cocoons on bark and nearby debris. Moths emerge in July and August to produce a second generation. These larvae spin cocoons and pupate in late September and October to overwinter.
Natural enemies control most populations. The control of brush and debris in and around plantings will reduce the best pupation sites. Chemical controls may be needed.