beneath the bark and often bore deep into the wood. Unhealthy and weakened trees 
are most susceptible to attack. 
Saperda discoidea F. breeds in dead and dying hickories and butternut from New 
York to Louisiana and Nebraska. Hickory trees infested with the hickory bark 
beetle are particularly subject to attack. Adults are 10 to 17 mm long. The male is 
blackish with reddish legs and lines of fine, grayish hair on the thorax. The female 
is reddish brown or nearly black, clothed with fine, yellowish hairs, and has two 
spots separated by a curved bar on the elytra. Eggs are deposited in bark crevices or 
in holes in the galleries of bark beetles during the late spring and summer. The 
larvae feed gregariously beneath the bark, making extensive meandering mines. 
Most of the larvae mature in | year. 
Saperda inornata Say, the poplar-gall saperda, breeds in the living branches 
and main stems of poplars and willows in the Northern and Central States (936). 
Adults are black with fine, gray hairs and are about 12 mm long. Eggs are laid in U- 
shaped slits in the bark. Callous tissue forming over these slits causes the formation 
ot globose galls. The larvae mine around the stem and then bore into wood, making 
galleries about 25 mm long that run parallel to the axis. The life cycle requires | or 
2 years. Usually the infested twigs are not killed. Branches or small stems bearing 
numerous galls may stop growing, however, and become subject to windbreakage. 
Growers should avoid establishing new plantings near heavily infested stands 
(1336). 
Saperda obliqua Say, the alder borer, breeds in the bases of living alders and 
sometimes birch in the Northern and Central States. The adult is reddish brown and 
from 10 to 20 mm long. There are two dark bands on the thorax and four oblique 
bands on the wing covers. Larvae feed first beneath the bark near the base, often 
girdling the stem. Later they bore into the stem and tunnel upward for 8 to 15 cm. © 
Swollen areas appear at points of attack on stems that survive, and large amounts of 
frass are pushed out through the openings at the egg scars. Alders in ornamental 
plantings are frequently killed. 
Saperda fayi Bland, the thorn-limb borer, occurs in the Northeast and Midwest 
and breeds in the twigs of hawthorn causing gall-like, gnarly swellings. Adults are 
reddish brown and about 12 mm long. There is a white stripe on each side of the 
thorax that extends up to the base of the elytra. The elytra bear two white spots at 
the base and tip, and a single large one in between. Infested twigs are subject to 
windbreakage. S. moesta LeConte causes the formation of globose galls on the 
stems and branches of poplar and willow in the northern parts of the United States. 
Adults are dark brown to black and about 10 mm long. S. /ateralis F. breeds in dead 
hickory, elm, basswood, oak, cherry, and in hickory sprouts. Adults are black or 
brownish black with the head, thorax, and elytra margined by broad, red lines and 
are about 12 mm long. The male has a tooth on each of its claws. S. imitans Felt & 
Joutel breeds in dead hickory, willow, and basswood; S. cretata Newman, in living 
apple and the limbs of living hawthorn; S. mutica Say, in dead willow. 
The elm borer, S. tridentata Olivier, occurs in southeastern Canada and 
throughout the Eastern United States and breeds in dead and dying American and 
slippery elms. The adult is grayish or fawn colored and from 9 to 17 mm long (fig. 
133). An orange-yellow or yellowish band extends from the head to the tip of each 
wing cover, twin black spots occur below these bands on the thorax, and there is a 
crossband at the base of the wing covers followed by two oblique bands. Full-grown 
larvae are about 12 to 15 mm long. 
298 
