HOST: All species of pine,
but prefer loblolly,shortleaf,
Virginia, pond and pitch pines
southern pine beetle (Dendroctonus
frontalis) is the most destructive
forest insect in the South.
Weakening of trees by
flooding, windstorms, and especially
drought commonly precedes outbreaks.
Trees of all sizes are attacked, but
usually trees larger than six inches
in diameter are infested first.
brown to black beetle is about 1/8
inch long. Its hind end is rounded,
in contrast to the scooped out
posterior of the Ips beetle. Larvae
are white with a reddish-brown head and the
pupae pure white. Fully-grown larvae and
pupae are approximately 1/8 inch in length.
Eggs are white, and easily visible to the
SIGNS OF ATTACK:
The first indication of attack is
usually yellowing or browning of
needles. The trunk will usually
reveal white, yellow or sometimes
red-brown pitch tubes, about as
large as a wad of gum. Under drought
conditions, pitch tubes may be very
small or absent, and only
reddish-brown boring dust will be
present. Removal of the bark will
show a distinctive winding "S"
shaped gallery pattern. This pattern
is quite different from the "Y" or
"H" shaped gallery patterns of the
Ips beetle and is a good
identification characteristic. In
active spots, trees in the center
have dark reddish-brown foliage.
Foliage will change to light
greenish or yellowish green on the
edges of active spots.
LIFE CYCLE: Adult
beetles are usually attracted to
weakened trees. In epidemics, they
attack trees that appear healthy and
vigorous. Initial attacks are in the
mid-trunk and then the length of the
tree. Adult beetles bore through the
bark and excavate long winding "S"
shaped galleries. Eggs are laid in
niches along the galleries. Larvae
feed in the cambium until grown, and
then excavate cells near the bark
surface in which to pupate. After
pupation, adult beetles chew through
the bark and emerge. The complete
cycle of the attack takes from 25 to
40 days, depending on the
has led to a better understanding of
the beetle and its relationship to
the tree and the stand. With this
information, we can prevent beetle
attack or more effectively manage an
outbreak. The goal of an SPB
prevention program is to identify
pine stands growing under conditions
preferred by the beetle. High hazard
stands should be managed to favor
vigorous tree growth and promote
natural resistance to beetles.
Red-topped pines in SPB spotTo rate
a pine stand for SPB hazard, obtain
information on pine basal area,
total basal area, stand age and site
index. This information is taken at
each plot, with plots generally five
chains apart (each plot represents
approximately 2.5 acres) and put
into a formula to determine the
score associated with a hazard
class. The following formula
determines SPB hazard for a stand.
Score = 1.8342 (Pine BA)
+ 0.4085 (Total BA) + 0.705
+ 0.88 (Site Index)
220 or above
168 to 219
62 to 167
11 to 61
10 to 0
total basal area is 130 sq.
ft./acre, pine basal area is 120 sq.
ft./acre, stand age is 27 years,and
site index is 109.
Score = (1.8342 x 120) + (0.4085 x 130) +
(0.705 x 27) +(0.88 x 109) - 206.315 =
The score of 181.85 is between 168 to 219
means the relative hazard rating is "High."
To reduce SPB losses in pine stands rated as
medium or high hazard, consult a registered
forester for management advice. Depending on
the stand, the forester may recommend one or
more of the following actions:
High SPB Hazard Stand
After thinning high SPB Hazard Stand
- Thin to basal areas of 70-100 sq.
ft./acre to promote rapid tree growth
and resistance to beetles.
- On sandy soils, use borax on tree
stumps to prevent annosus root rot.
- Harvest and regenerate over-mature
- Conduct a prescribed burn to reduce
- Treat unwanted hardwoods in the pine
stand with herbicide to reduce
- When practical, remove high hazard
trees preferred by beetles, e.g., those
damaged by lightning, ice, logging or
Photo Credits: A Field Guide for Ground
Checking Southern Pine Beetle Spots,
Handbook No. 558, Tim Tigner, Virginia
Department of Forestry,
www.forestryimages.org, and Wes Nettleton,
USFS, Region 8