Southern Pine Beetle Lands
in Ohio
(Contributed by Chris
Smid)
As the Gypsy Moth continues to move
across Ohio from the north and east, a new forest pest is moving in from the
south. Since January 2001, outbreaks of
Dendroctonus frontalis Zimmermann, more commonly known as the Southern
Pine Beetle, have been confirmed in Adams, Jackson, Meigs, and Pike counties.
Recognized as the most destructive pest
in the Southeastern United States, the Southern Pine Beetle (SPB) has caused
hundreds of millions of dollars in damages over the past several years. With a range from Arizona and Central
America through Texas and Florida north to southern New Jersey, Pennsylvania,
and now Ohio, the SPB typically favors Loblolly and Shortleaf Pine. However, the SPB is known to attack and kill
most southern yellow pine species and in 2000 the SPB killed Eastern White
Pines in the southern Appalachians, and even attacked Norway Spruce and Eastern
Hemlock.
Here in Ohio, the SPB attacks have
occurred in 5 to 14 year old plantations of Loblolly and Pitch X Loblolly
pine. The "spots" as these
outbreaks are known, have ranged in size from a few trees to over one
acre. SPB galleries, larvae, and adult
beetles may be found in or under the bark on dead trees. The actual insect is smaller than a grain of
rice and blackish-brown in color. On
more recently attacked trees (those with some green foliage) the bark will be
tighter, but if you cut some off with a knife, the galleries will still be
apparent. Dust from the boring beetles
often accumulates in cracks on the bark or at the base of the tree. Pitch tubes can form as the tree tries to
repel the beetles. Once through the
bark, the SPB bores out galleries to lay eggs, damaging the trees phloem and
introducing a blue stain fungus into the sapwood that eventually inhibits water
flow in the tree. Salvage logging,
cutting and piling, or cutting and burning are the commonly practiced control
measures. Cutting the infested timber
plus a buffer of live trees (typically 1 to 2 tree lengths wide) around the
spot will cause direct solar heating of the felled timber, and improved air
movement. It is believed the increased
temperatures will kill or drive off the beetles, and the air movement will disperse
the aggregation pheromones used by the SPB to attract other beetles and cause
infestations.
While SPB infestations have been
reported in Ohio at least twice during the 20th century, southern
Ohio is on the very northern edge of the SPB's range and outbreaks are
rare. With a good growing season in
2000, it is hoped that healthy trees and a cold 2000-2001 winter will repel
this most recent incursion of the SPB.
In an effort to quantify the SPB population and evaluate the potential
for serious outbreaks in the future, the Division of Forestry
and Mead Paper have installed 18 SPB
traps in 6 southern Ohio counties.
Trapping began in late April and will continue for four weeks. Rumor has it that the SPB's are being found
in the traps, but so are Clerid beetles that prey on the SPB. Stay tuned throughout the summer as we
continue to monitor this situation closely.
*For
photos and additional information regarding the biology and habits of the SPB
you check out the USFS Forest
Insect and Disease Leaflet on SPB.