Eastern poplar buprestid
Descarpentriesina cyanipes (Say)
From: Solomon, J.D. 1995. Guide to insect borers of North
American broadleaf trees and shrubs. Argic. Handbk. 706. Washington, DC:
U.S. Department of Agriculture, Forest Service. 735 p.
Hosts. Poplar, willow. Has been reared from eastern
cottonwood, black cottonwood, quaking aspen, bigtooth aspen, and willow (Chamberlin
1926, Evans 1957, Wellso and others 1976). Beetles have been collected
from ash, sycamore, and pine, but it is unlikely that these serve as larval
hosts.
Range. The most common and widely distributed member of Descarpentriesina
in North America. Recorded from southern Arizona northward along the Rocky
Mountains to the Yukon, eastward to New Brunswick, and southward to the Gulf
Coast; it does not occur along the Pacific Coast (Chamberlin 1926, Evans 1957).
Description
Adult. Elongate to moderately slender, somewhat oval, dark
bronze beetle (Chamberlin 1922, Evans 1957). Head sparsely covered with
fine pubescence and slightly flattened along with pronotum. Elytra with
dark bluish bronze, abbreviated, elevated, irregular lines tinged with coppery
bronze. Females slightly broader and darker than males. Beetles 9.3
to 18.0 mm long and 3.25 to 7.00 mm wide.
Larva. Clublike or pest like in shape with thoracic segments and
head moderately flattened (Burke 1917a). Thoracic plates smooth and marked
dorsally with inverted V, and ventrally with one groove (USDA FA 1985).
Larvae yellowish white with dark brown heads, measuring 17.8 to 25.4 mm long.
Biology. Adults emerge late April through June in its southern
range but have been taken in flight as late as August and September in its
northern range (Essig 1929). On sunny days, adults are frequently found
resting, crawling, and ovipositing on host trees. Females prefer weakened
stems for oviposition. It has also been reared from galls of Saperda
concolor LeConte in aspen and from galls of Agrilus criddlei in
willows (Chamberlin 1922, Wellso and others 1976). Larvae initially
excavate small cavities just under the bark, then extend their galleries into
the wood usually to the pith of stems up to 25 mm in diameter. In large
stems, most larvae burrow to about 12 mm then continue longitudinally.
Larvae overwinter within their galleries. Mature larvae prepare chambers
typically at one end of the galleries and pupate. New adults gnaw exit
holes directly through the bark to emerge. A generation is completed in 1
to 2 years (USDA FS 1985).
Injury and Damage. This beetle commonly attacks stems 12 to 32
mm in diameter, but it is occasionally found in stems up to 75 mm in
diameter. The earliest evidence of injury is small wet or stained spots on
the bark. Little or no frass is ejected from the sites. The bark
sometimes cracks open, exposing a frass-packed cavity just beneath.
Galleries are oval to irregular in cross section and 6.4 mm in diameter, extend
6.4 to 12.7 mm into the wood, and run 5 to 30 cm longitudinally within the
stem. Galleries are almost entirely filled and packed tightly with a frass
mixture of fine particles and short fibers. Oval-elongate exit holes 2.3
to 4.8 mm across can be found in the bark after beetles emerge. Healed
wounds leave irregularly shaped scars over the entrances and small oval to round
scars over the exit sites. Beetles usually attack wild and ornamental
trees that are weakened, injured, or decadent. In its southern range, this
buprestid prefers the lower branches of cottonwoods that are weakened, dying, or
being shaded out and self-pruned (Solomon and Wellso 1983). This borer
rarely attacks boles of healthy trees and is found largely in weakened branches,
so it might even be considered beneficial in helping the tree to self-prune its
lower branches, thereby improving the quality of the wood.
Control. Light incidence of woodpecker predation had been
observed, but no parasites have been found. Maintenance of high vigor in
ornamental and other high-value trees can prevent infestation. Direct
controls have not been needed.
Larva(e) gallery. James Solomon,
USDA Forest Service. |
Damage attacks on stems. James Solomon,
USDA Forest Service. |
Damage bark removed to expose entrances. James Solomon,
USDA Forest Service. |
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