Viceroy Butterfly (Limentis archippus (Cramer))

Morris, R.C.; Filer, T.H.; Solomon, J.D.; McCracken, Francis I.; Overgaard, N.A.; Weiss, M.J. Insects and Diseases of Cottonwood. New Orleans, LA. U.S. Department of Agriculture, Forest Service; Southern Forest Experiment Station; State and Private Forestry Southeastern Area. Gen. Tech. Rep. SO-8. 1975. 41 p.

The viceroy butterfly is a common defoliator in cottonwood plantations throughout the United States. During most of the growing season, caterpillars feeding on leaves are of little concern; but later when few new leaves are being formed, caterpillars eat tender terminal tissues and buds, killing 8 to 10 inches (20 to 25 cm) of the terminals. New growth from lateral buds results in multiple-forked crowns the next year. These malformed trees will produce less pulpwood, saw logs, and veneer than healthy trees. The viceroy is normally not a serious pest in nurseries.

The first signs of attack are caterpillars on ragged, partly eaten leaves near branch ends. Late in the season, damaged terminals turn black and die. During the winter, leaf petioles fastened to the branch by silk will have small tubes of rolled leaf blade in which small caterpillars are hibernating.

The orange and black adult resembles the monarch butterfly but is smaller. It has a narrow black line across the hindwings and one row of white spots in the black marginal band of the wings. The full-grown caterpillar is about 1 1/2 inches (38 mm) long and has a large, bilobed, pale green head. The body is olive green and white or brown and white. Two barbed, club-shaped, brown tubercles on the thorax are topped by two smaller tubercles armed with spines.

Eggs are laid on the leaves. The solitary caterpillars each consume several leaves during their growth. The full-grown larva secures itself to a leaf stem or branch and changes to a shiny brown and white chrysalis (pupa) from which the adult butterfly emerges after a few days. Two generations per year are recorded, but more may occur in the deep South.

In late fall, a small caterpillar fastens a leaf petiole to the branch with silk and then cuts away all but the base of the leaf blade. This part of the blade is rolled and fastened into a short tube in which the 1/2-inch (12 mm) long caterpillar spends the winter. In spring, the caterpillar emerges and feeds on new leaves.

No natural controls are known.