-- Many of the large oaks in the East have been attacked by this borer,
resulting in defects and serious degrade in the timber. Valuable shade
trees in parks and cities are sometimes injured.
Insect (figure 21a). -- Adult borers are about 1 inch (25mm) long,
light brown, robust beetles with long antennae. The shiny white, robust
larvae have tiny legs on the thorax.
Injury. -- Initially, tiny pin-holes with fine, extruded frass are
present. Later, entrance holes become larger and sap-stained, followed
by ejection of granular frass (figure 21b). A few excelsior-like fibers
are present in frass just before pupation. Tunnels are about .5 inch
(12 mm) in diameter and 6 to 10 inches ( 15 to 25 cm) long (figure 21c).
-- The pest has a 2-year life cycle. Eggs are laid in July and August
on the bark. The larva mines under the bark during the first year, tunneling
into the wood the second year. Pupation occurs within the gallery and
the adult exits through the bark near the entrance.
-- Maintain high tree vigor. Remove brood trees. "Worm-out" with knife
or wire. Control in high-value trees with trunk spray or gallery fumigation.