including all of the leaves on a branch in a web (fig. 136). Heavi- 
est infestations apparently occur in the more open portions of 
the crown of trees growing in the most exposed positions in the 
stand. When the larvae become full-grown, they leave the nest 
and drop to the ground on strands of silk. The winter is spent as 
a prepupa in a cocoon spun in the duff on the ground. There ap- 
pears to be only one generation per year (294). 
This species had never been considered economically important 
until it was shown to be a major factor leading to the develop- 
ment of “maple blight,’’ a condition responsible for the killing of 
thousands of valuable sugar maples in Wisconsin during the late 
1950’s. 
Other species of Tetralopha occurring in eastern United States 
are T. militella Zell., feeding on sycamore; and T. melanogrammos 
Zell., on sweetgum. Another species identified only as being near 
T. asperatella is sometimes abundant locally on beech in New 
England. The larva is yellowish green and has two pale-brownish 
stripes running down the back. 
FAMILY PHYCITIDAE 
This family contains many important tree-infesting species. 
The larvae differ considerably in their habits. Some feed on 
rolled or folded leaves; some construct silken cases and feed from 
inside them; at least one is a predator of scale insects; and many 
feed as borers in shoots, bark, roots, cones, nuts, or fruits. Mem- 
bers of the family are rather difficult to classify because of the 
variability of many of their distinguishing characters. 
The pecan leaf casebearer, Acrobasis juglandis (LeBaron), oc- 
curs from southern Canada to Florida and Texas, and the larva 
feeds on the buds, flowers, and leaves of hickory, walnut, butter- 
nut, and pecan. The adult is a grayish moth with a wingspread 
of 14 to 17 mm. The forewing is blackish at the middle of the 
costa and reddish near the middle of its inner margin. Full-grown 
larvae are olive green and about 16 mm. long. The larvae feed 
during two growing seasons. The first summer, they feed on the 
lower surfaces of leaves. They spend the winter in small cases 
attached to buds or twigs. The following spring, they resume 
their feeding by eating into bud after bud and constructing new 
cases as necessary. Finally, before becoming mature, they move 
to the leaves to feed. Here, they often chew into the petioles and 
cause the leaves to break off and fall. This, plus the injury to the 
buds, often results in serious damage to infested areas (295). 
Acrobasis caryivorella Ragonot occurs in southern Canada and 
throughout eastern United States and the larva feed on the folli- 
age of hickory, walnut, and pecan. The adult has dark bluish- 
gray to nearly black forewings and a wing expanse of about 20 
mm. The larvae are dark grayish-green and about 19 mm. long. 
In the spring, they feed by boring into new shoots which they tie 
together with silken threads. Full-grown larvae construct oval 
cocoons in which they pupate. Two generations per year have 
been recorded in Texas. In Florida, there are probably three or 
four generations per year. This species has seriously damaged 
pecan seedlings in nurseries in Florida and Texas. 
308 
