the wood, excavating extensive mines and pushing quantities of frass to the outside 
through a hole in the bark. There are two generations a year. This species 1s 
especially injurious to mesquite cordwood. Fenceposts also are greatly weakened or 
destroyed. Information on control has been published (258). 
The banded hickory borer, Knulliana cincta (Drury), occurs throughout much 
of the Eastern United States where it breeds in the dead branches and trunks of a 
wide variety of hardwoods, such as hickory, walnut, oak, eastern hophornbeam, 
plum, and apple. Hickory appears to be preferred. The adult (fig. 126) is dark 
brown and from 16 to 30 mm long. The body is clothed with fine grayish hairs, and 
there is a short sharp spine on each lateral margin of the thorax. Each elytron has an 
oblique yellow spot near the base and two slender spines at the tip. Eggs are 
deposited during the summer beneath the bark or directly on the wood of recently 
felled, dying, or dead trees. The larvae feed beneath the bark during the remainder 
of the summer, deeply scarring the wood and pushing out huge quantities of 
granular frass through small openings in the bark. During the fall and following 
summer they bore into the wood and mine it extensively. Pupation occurs in the fall 
or spring between wads of fibrous frass at the end of the tunnel. The life cycle 
probably requires 2 years for completion. Cordwood, logs, posts, and rustic work 
are frequently seriously damaged by the species. The prompt milling and seasoning 
of summer-cut wood are recommended control practices. 
yey 
F-480484 
Figure 126.—Adult of the banded hickory borer, 
Knulliana cincta. 
The cottonwood borer, Plectrodera scalator (F.), breeds in the bases and roots 
of living cottonwood, poplars, and willows mainly in the Southern States, but is 
also found from New York and Michigan to Montana and Texas. The adult is 25 to 
38 mm long and beautifully marked. The ground color is black, but this is obscured 
by patches and cross stripes of fine, pure white hairs that surround black, hairless 
areas (fig. 127A). 
Adults appear in late spring or early summer and feed on the tender shoots of 
young trees. These shoots often break, shrivel, and turn black. Eggs are deposited 
in pits chewed in the bark at the base of the tree, at just above, or below the ground 
line. Trees of all sizes are subject to attack. Larvae (fig. 127B) begin boring at the 
289 
