-- This borer attacks the lower trunk of red and white oaks throughout
the East. In the South, attacks are most common between root flanges
of large red oaks. Damage includes degrade, entries for decay and nursery
Insect (figure 20a). -- The purplish-gray larva has a black head
and a brown thoracic shield, and is about 1 inch (25mm) long. Adults
are colorful, black and orange banded, beelike moths with a wing expanse
of 1.5 inches (37 mm).
Injury (figure 20b). Sap spots and fine frass first appear. Later,
granular frass is ejected in clumps from the .3 to .6 inch (9 to 15
mm) entrance holes. There is little mining under the bark. Galleries
are .3 inch (9 mm) in diameter and 4 inches (10 cm) long in the wood,
and shaped much like those made by carpenterworms (figure 20c).
-- Moths emerge during June and July and deposit eggs in bark crevices.
Eggs hatch in 15 to 18 days and the larvae tunnel into the bark and
wood of host trees. Pupation occurs within the gallery. A generation
requires 2 years.
-- Open-grown trees are most susceptible, thus maintain a well stocked
stand. Identify and remove brood trees. Prevent or minimize injuries.
Larvae can be "wormed-out" with a knife and wire. Insecticides will
protect valuable trees. Individual borers can be killed by gallery fumigation.