Southern Pine Bark Beetle
Description:
The usual method of detecting this insect is by observing masses of pitch (pitch tubes)
on the bark of dying pine trees. Adult beetles are tiny, being 1/16 to 3/16 inch long,
dark brown to black cylindrical beetles. Diagnosis of dead trees is made by the appearance
of the pattern of galleries that appears S-shaped underneath the bark and outside of the
heartwood (in the phloem-cambium layer).
Life Cycle:
Adults emerge from a host tree and fly to a new host tree where they begin burrowing
into the bark to construct galleries. They release an attractant chemical (pheromone)
that attracts more beetles and mate. In galleries, adult females deposit eggs that hatch
in 3 to 34 days, depending upon temperature, into cream-colored, legless grub-like larvae
with brown heads. Larvae develop through four stages (instars) until they reach about 1/4
inch in length over a period of 15 to 40 days before pupating. Adults hatch within 17 days.
A generation from egg to adult can be completed in 26 to 54 days.
Pest Status:
Needles on infested pines turn first turn yellow and then red, before dropping.
Masses of resin (pitch) develop on the bark surface and fine brown to white boring dust
accumulates in bark crevices, underneath sites of infestation and at the base of the trunk.
Infested trees die quickly due to girdling action of galleries and a blue stain fungus.
Management:
Since most wood-boring insects are considered secondary invaders, the first line of defense
against infestation is to keep plants healthy. Proper care of trees and shrubs discourages
many borer pests and helps infested plants survive. Good sap f low from healthy,
vigorously growing trees, for example, defends the plant from damage by many borer pests.
* Choose and prepare a good planting site to avoid plant stress, freeze damage, sun scald and wind burn.
* Minimize plant stress and stimulate growth by using proper watering and fertilization practices.
* Avoid injury to tree trunks from lawn mowers, weed trimmers or construction.
* Promptly caring for wounded or broken plant parts using pruning or wound paint during
all but the coldest months of the year.
* Properly thinning and pruning during colder months.
* Removing and destroying infested, dying or dead plants or plant parts, including fallen limbs.
