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Manage Your Forest To Prevent SPB Damage |
What
is the Southern Pine Beetle (SPB)?
What
Factors Make Pines Susceptible to SPB Attacks?
What
Can I Do to Help Prevent SPB Attacks?
What
If an SPB infestation occurs?
What
Are the Signs of SPB Attack?
What
is Being Done to Monitor SPB?
Are
Management Assistance Programs Available?
What is the
Southern Pine Beetle (SPB)?
Photo: SPB (left) compared to grain of rice and
black turpentine beetle. Credit: Southern Forest
Insect Work Conference, www.forestryimages.org |
The
southern pine beetle (SPB) is an aggressive insect
pest that has devastated pines in yards and forest
tracts throughout northern and central Florida. Like
other species of bark beetles, populations of the
SPB feed in the inner bark of susceptible pines and
usually attack trees that are stressed due to overcrowding,
competition, injury, drought, disease or old age.
When these types of stressful forest conditions occur
in combination over a widespread area, SPB outbreaks
can develop, during which even healthy pines can be
mass attacked and rapidly killed. Such conditions
led to Florida's most extensive SPB outbreak in 2001,
when nearly 2,900 infestations were detected in 34
counties, covering 17,600 acres and resulting in the
loss of several million dollars of pine timber. |
PHOTO (left): Extensive pine mortality during an SPB outbreak on Florida's
Ocala National Forest.
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Forest management, however,
can help prevent SPB outbreaks and damage, as well as enhance
recreational opportunities, reduce the risk of loss from
wildfires, and increase the economic potential of forest
land. Good forest management pays in the long run. As a
non-industrial private landowner in Florida, you may qualify
to have a forest management plan drawn up for your property
at no cost, or to receive financial assistance with forest
management practices that reduce the risk of SPB attack.
What Factors Make Pines Susceptible
to SPB Attacks?
PHOTO: A dense, unthinned, susceptible stand. |
As young pine stands grow, trees begin to
crowd and compete with one another for space, sunlight,
water, and nutrients. In most plantations, this crown and
root competition begins as early as age 10-15 years, or
even earlier on better-quality sites. If a dense stand is
not thinned by this point, radial growth and vigor decline
and trees become very susceptible to SPB and other bark
beetles. Similarly, pine stands with a buildup of competing
hardwood and other underbrush beneath the main canopy are
susceptible to bark beetles, especially during droughts
or other periods of environmental stress. |
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PHOTO: Thick hardwood competition beneath pines. Credit: Jim
Meeker, USDA Forest Service |
Other factors that increase stand susceptibility
to bark beetles include: loss of vigor associated with age,
disease or root damage; injuries or wounds to pines; and
inappropriate pine species for a given site.
What Can I Do
to Help Prevent SPB Attacks?
Thin dense, overcrowded pine stands to increase the vigor
of remaining trees, make beetle spread more difficult due
to wider tree spacing, and produce higher value wood products
(sawtimber) at final harvest. Thin stands to a basal area
of 80 square feet per acre or less, giving individual tree
crowns adequate room to expand.
Prescribe burn to reduce competing hardwood vegetation and underbrush
beneath pines, reduce wildfire hazard, and enhance certain
wildlife, recreation, and aesthetic values. Often, very
dense buildups of competing vegetation under the pine canopy
should first be reduced by mechanical means.
PHOTO: A stand managed through thinning and prescribed burns |
Minimize or avoid wounds to pines during harvesting operations to
reduce the production of pine odors that attract bark beetles.
For similar reasons, don't conduct thinnings during bark
beetle outbreaks or near active infestations.
Harvest
and regenerate stands overmature, senescent pines. If removal
of old pines conflicts with other management objectives,
monitor such pines frequently for bark beetle activity.
Remove pines weakened by disease, injury, lightning or other
stress to increase overall stand vigor and resistance to
bark beetles. |
PHOTO: Longleaf Pine
|
Avoid planting pines off-site, especially loblolly and shortleaf pines, which are more susceptible to the SPB than longleaf (pictured) or slash pines. A forester can help you determine which species are appropriate for a given site.
Promote a diversity of tree species and ages in the forest landscape, which can make susceptible trees or preferred host species more difficult for bark beetles to find.
What If an SPB
infestation occurs?
Due to a very effective odor-driven communication system used by the SPB, small infestations can expand by more than 50 feet per day, quickly resulting in many acres of dead pines. If you detect enlarging patches of recently killed or dying pines on your property, contact your county forester or county extension office for an evaluation of the situation. If they determine the problem is an SPB infestation, the best control option is usually to cut, remove, and process all infested trees, plus a buffer strip of uninfested green trees as soon as possible.
What Are the Signs of SPB
Attack?Signs of SPB attack may include: popcorn-sized
resin globs or "pitch tubes" in the bark crevices, winding
"S-shaped" galleries under the bark, and clusters of pines
with crowns fading from green to yellow to red. Other bark
beetle species (Ips, black turpentine beetles) can produce
similar symptoms, but the S-shaped gallery pattern under
the bark is distinctive of the SPB. |
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PHOTO (left): SPB galleries under the bark
Credit: Ronald F. Billings, Texas Forest Service,
www.forestryimages.org |
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What is Being Done to Monitor SPB?
Each spring, the Florida Division of Forestry
conducts an SPB trapping survey in central and northern
Florida. This survey monitors the numbers of SPBs and their
predators captured in pheromone-baited flight traps, and
the results are used as an early-season prediction of SPB
activity levels. Also, the Division of Forestry conducts
aerial survey flights to detect and monitor SPB infestations.
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Are Management
Assistance Programs Available?
Programs that provide technical and financial
assistance with forest management planning and practices
are available periodically. To find out what programs may
be available currently, contact your county or district
Division of Forestry office. |
Good forest management
practices help prevent
bark beetle attacks and result
in more productive pine stands. |
| Due to the limited options for remedial control
of bark beetles, the best way to prevent losses is to manage
pine stands such that they are healthy, vigorous, and resistant
to attack. Give pines plenty of sunlight, space to grow,
freedom from competing plants, and protection from injury,
and plant on proper growing sites. All of these practices
are compatible with the production of high-value wood products
and other forest management goals. |
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Authored
By:
Bud Mayfield - Florida DACS Division of Forestry
Galen Moses - Florida DACS Division of Forestry
Jarek Nowak - University of Florida IFAS
Rev. June 2004
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Other Sources of Information: |
| Florida Division of Forestry:www.fl-dof.com |
| Bark Beetles of North America:www.barkbeetles.org |
| Forest and Shade Tree Insects of Florida:http://eny3541.ifas.ufl.edu
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| Southern Pine Beetle Internet Control Center:http://whizlab.isis.vt.edu/servlet/sf/spbicc/
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| USDA Forest Service, Forest Health Protection, Southern
Region:http://www.fs.fed.us/r8/index.html
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| University of Florida-IFAS Extension:http://extension.ifas.ufl.edu
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University of Florida School of Forest Resources and
Conservation Extension:www.sfrc.ufl.edu/Extension/
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