-- This borer attacks red and white oaks throughout the East. Trees
weakened by drought, defoliation, or other factors are most susceptible.
Larvae destroy the cambium and girdle the tree. Mortality can be extensive
in weakened stands.
Insect. -- Adult beetles are about .2 to .5 inch (6 to 12 mm) long,
slender, and black with a light yellowish stripe on each wing cover.
Larvae are white, slender, flattened, about 1 inch (25 mm) long, and
have two spines at the rear end.
Injury (figure 23). -- Larvae excavate winding mines in the inner
bark and outer sapwood of the main trunk and large branches, frequently
girdling the tree. Attacks usually begin in the tree tops and extend
downward as the trees continue to weaken. D-shaped emergence holes are
evidence of infestation.
-- Adults emerge during spring and early summer and deposit eggs in
bark crevices. Eggs hatch in 10 to 14 days and the larvae burrow through
the bark and cambium. They overwinter in cells in the bark and pupate
the following spring. There is one generation per year.
-- Control is mainly a matter of preventing attacks through cultural
practices that promote tree vigor. Spraying to protect foliage from
defoliators is recommended in some areas. Trunk sprays offer some promise.