Setting Control Priorities for the Southern Pine Beetle - Forest Pest Management Technology Update

Setting Control Priorities for the Southern Pine Beetle
Forest Pest Management Technology Update

Ron Billings - Head, Pest Control Section, Texas Forest Service, Lufkin, Texas.

USDA, Forest Service, Forestry Bulletin R8-FB/P 8, Southern Pine Beetle Fact Sheet Number 3, slightly revised April 1984.

Setting Control Priorities for the Southern Pine Beetle

All southern pine beetle spots (groups of infested trees) do not have the same control priority. The following guidelines should help you set priorities for controlling individual spots.

A. Classify the infested trees according to the stage of attack shown below.

Stage of Attack
Symptom	Stage 1 Fresh attacks	Stage 2 Developing broods	Stage 3 Vacated trees
Foliage	Green	Green; fade to yellow before new generation	Red; needles falling
Pitch tubes	Soft; white to light pink	Hardened; white	Hard; yellow; crumbles easily
Checkered beetles	Adults crawling on the bark	Larvae in SPB galleries; pink or red; 1/2 inch long	Larvae and pupae are purple; occur in pockets in the other bark
Bark	Tight; hard to remove	Loose; peels easily	Very loose; easily removed
Color of wood surface	white, except close to new adult galleries	Light brown with blue or black sections	Dark brown to black; may have sawyer galleries
Exit holes	----	May appear where parent beetles left the tree	Numerous; associated with brood adult emergence
Ambrosia beetle dust	----	White; begins to appear around the base of trees	Abundant at the base of trees

B. Collect spot expansion data:

Walk completely around the spot and look for stage 1 trees, which indicate the area of most recent beetle activity. Areas with stage 1 pines are called "Active Heads." Check to see if the spot is expanding in more than one direction. Large spots can have more than one "Active Head."
Determine the number of stage 1 and 2 trees. For large spots that have more than 50 trees, it is not necessary to examine each tree. Just walk the boundaries and estimate the number of these trees in the spot.
From a location about 20 feet (6 m) in front of the active head(s), determine the pine basal area (a measure of stand density) in square feet per acre. A 10-factor prism is useful for this purpose.
Note whether most trees in the spot are pulpwood (less than 9 inches in diameter) (23 cm) or sawtimber size (more than 9 inches in diameter).
If only stage 3 trees are present, control is not necessary.
Determine the control priority for the spot. See C, below.

C. Guide to southern pine beetle control priorities (May through October):

	Key to spot growth	Your spot's classification	Risk-rating points
A.	Stage 1 trees Fresh attacks	absent present	0 30
B.	Stage 1 (fresh attacks) and Stage 2 trees (developing brood)	1 to 10 11 to 10 21 to 50 more that 50	0 10 20 40
C.	Pine basal area (ft²/a) or stand density at active head or heads	less than 80 (low density) 80 to 120 (medium density) more than 120 (high density)	0 10 20
D.	Stand class by average d.b.h. (in inches)	pulpwood (9 inches or less) sawtimber (more than 9 inches)	0 10

Add up the risk rating points that apply to your spot:

	Score	Control priority
	70 to 100	High
	40 to 60	Medium
	0 to 30	Low