-- The oak timberworm is a major cause of defect and degrade in the
red and white oaks in the East. Attacks are most commonly associated
with wounds on mature trees.
Insect (figure 24a). -- Adults are brownish black, brentid weevils
about 1 to 1.4 inches (25 to 35 mm) long. The female has a narrow snout,
while the male's mouth-parts are broad and flattened. The larvae are
white, elongate, cylindrical, and curved (figure 24b).
Injury. -- Attacks usually occur at blazes, around other borer entrances,
and other wounds that expose the sapwood. White, powdery frass at egg
sites on exposed wood is good evidence of infestation. Winding tunnels
.1 inch or smaller (0.2 to 3 mm) in diameter, characterize damage in
-- During spring and early summer, females chew cylindrical holes into
the sapwood and lay single eggs. Eggs hatch in a few days and the larvae
bore almost through the tree then "U-turn" back across the grain to
the point of origin. Pupation occurs in the gallery, and adults emerge
through circular holes near the egg site. The life cycle requires 2
to 3 years.
-- Trees should be protected from wounds and injuries, including other
borer attacks to largely prevent infestation by the oak timberworm.