Mature fall cankerworm larva.
The winged male and wingless female adults emerge on mild days in November and December and mate. Females lay 6-300 eggs in neatly arranged masses encircling small branches and twigs. The pale green larvae hatch in late April or early May. As they mature they may remain light green, or change to a very dark brownish-green depending on the host. Newly hatched inch-worms (larvae) of the fall cankerworm chew small holes in expanding leaves of their hosts, or may completely skeletonize the leaves. Mature larvae consume all but the mid-rib and major veins of the leaf. Feeding is usually completed in four to five weeks, at which time larvae drop to the ground to pupate in the soil.
Cold, wet weather during the early larval period, and parasitization, are responsible for sudden declines in established populations. Chemical control has also been effective. A small wasp, Telenomus alsophilae Viereck, has caused a sharp decline in outbreaks of cankerworm populations. Usually, however, outbreak conditions must exist for several years before the parasite can attain the density needed to cause a decline.
Female cankerworm adult depositing eggs.
A LOOPER, Phigalia titea (Cramer)
Larvae of this moth, one of the measuring worms, have periodically been responsible for scattered mortality of hardwoods throughout the eastern United States. Mortality is most likely to occur in stands on low-quality sites, particularly during periods of drought which favor this insect’s development and further weaken infested trees. This species is likely to be found in almost any hardwood area in the eastern United States. The insect feeds on a wide variety of trees and shrubs. Host trees in the Southeast include oaks, hickories, black tupelo, and black locust.
Phigalia adult male moth.
Phigalia titea overwinters as a pupa. Adults emerge in late March to mid-April, and mate. The female lays her eggs in protected sites on branches and trunks of hardwoods. Eggs are most often laid in crevices and beneath the bark of dead branches. Eggs hatch in April, and larvae feed until early June. Larvae often feed on unopened buds, causing irregular holes in the developing leaves. Larvae first eat just the surfaces of leaves, but later consume all leaf tissue between the major veins. When larvae are dislodged by wind or feeding predators they fall or descend on a silken thread and continue feeding in the lower crown or on understory vegetation. Pupation occurs on the soil surface or in the litter.