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.
[Illustration: 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.
[Illustration: Phigalia larva.]
Weather regulates populations of this insect. Soil-inhabiting insects
and rodents are believed to destroy many pupae during the winter.