Southern States, the oaks, particularly those of the red oak group, 
are most heavily damaged. In the Prairie States, green ash is the 
chief host. Other hosts are black locust, elm, maple, willow, cot- 
tonwood, and occasionally fruit trees and ornamental shrubs 
(327). The adult is dark, slightly mottled, stout-bodied, and has 
orange and black hindwings. The female is lighter colored and 
considerably larger than the male and has a wingspread of 75 
mm. The posterior half of the hindwing of the male bears a large 
yellowish to orange spot with a black border. Full-grown larvae 
are greenish-white, are nearly naked, bear simple setae, and are 
50 to 70 mm. long. The head is shiny brown and armed with 
powerful, nearly black mandibles. The thoracic legs are yellowish, 
and three-jointed, and each bears a curved, pointed tarsal claw. 
Carpenterworm moths begin to appear in late April in the South, 
the last week of May in the Central States, and the first week of 
June in more northerly regions. The female deposits upwards of 
450 to 800 eggs in groups in bark crevices, near wounds, or under 
vines, lichens, or moss. Young larvae bore directly to the inner 
bark, or enter it through openings, and feed there until about 
half-grown. Then they bore into the wood, their tunnels angling 
upward in the sapwood and straight upward in the heartwood. 
Feeding may be finished in one year in the Deep South but may 
continue for 8 or 4 years in the North. Tunnels are kept open and 
enlarged as needed by the growing larvae; eventually they may 
reach a diameter of 18 mm. and a length of 375 mm. Mature 
larvae line their tunnels with loose, silky, yellowish-brown webs. 
Pupation occurs at the upper end of the tunnel. Before completing 
its transformation to an adult, the pupa wriggles to the mouth of 
the tunnel and continues until its head and thorax are protruding. 
Even after the adult has formed and departed, the pupal case 
usually remains in place, sticking out of the opening. 
Carpenterworms seldom kill trees outright; although, heavily 
riddled, small trees may be broken off by the wind. The greatest 
damage results from the degrade of lumber cut from infested 
trees. The overall value of rough-cut, oak lumber may be reduced 
by as much as 15 percent. Open-grown trees, or trees growing on 
poor sites such as dry ridge tops or ridge slopes, are especially 
subject to attack and damage. 
Little is known about natural control of the carpenterworm. It 
is believed, however, that predation by woodpeckers on larvae and 
kingbirds on adults frequently accounts for the destruction of 
fairly large numbers. Insect parasitism appears to be inconse- 
quential. No satisfactory method of control in the forest is 
known, although the removal or killing of heavily infested weak, 
deformed, cull trees should, however, be helpful in reducing the 
intensity of infestations. Shade trees can be protected by painting 
injuries with wound dressing. Larvae in small trees can be killed 
by probing their tunnels with a wire. 
The little carpenterworm, Prionoxystus macmurtret (Guer.), a 
species very similar to the carpenterworm, is widely distributed 
in eastern Canada and eastern United States. The larvae are 
borers in oaks, and their habits are similar to those of the car- 
penterworm. They spend their first summer in the outer layers of 
bark and the second in the sapwood. During the third summer, 
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