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Suppression is accomplished by an integrated
approach in which three recommended techniques are involved. Emphasis is placed on control
by timely removal and utilization of merchantable infested material. Unmerchantable
material (small trees, infested bark, infested tops, etc.) should be either piled and
burned or, as a last resort, chemically treated. Control efforts should be a year-round
project; although, winter control is particularly important because brood densities tend
to be higher and concentrated in a fewer number of trees. Research has indicated that
control of one infested tree during the winter months may prevent 10 trees from becoming
infested the following spring.
(1) Removal of Infested Trees by
Salvage.
When infestations occur in trees of merchantable
size and are readily accessible, infested trees should be removed. Because time is of the
essence, logging of the infested material should begin IMMEDIATELY.
To minimize the possibility of spreading beetle
infestations, prompt processing of infested material at nearby mills is recommended. Slabs
and infested bark should be destroyed by chipping or burning. Encourage the infested logs
to be used first. If the logs are going to lay on the log deck for several days, spray the
logs.
Success in southern pine beetle salvage control
hinges upon removing all pines with fresh attacks and those with developing beetle broods.
The best insurance is to cut a buffer strip of uninfested green pines around the active
head of a spreading spot. This tactic interrupts the beetles' attractant source and stops
their advance. The buffer strip also provides a margin of error, just in case infested
pines were initially overlooked.
WIDTH OF STRIP - The easiest rule is to make the
width the same as the height of the infested trees. Example: The infested trees are
65-feet tall; cut the buffer to a width of 65-feet.
WHERE TO START MARKING THE BUFFER - Start from
the freshly attacked green pines and make the buffer from there into the green, healthy
pines.
WHERE TO START CUTTING - Start with the
outermost green pines and cut back towards the old, "dead," vacant pines (those
are the ones with very loose bark which can be removed easily). There is no need to cut
these "dead" trees. For effective control, cut only the green, freshly attacked
pines and pines with developing broods. In the summer, these generally are the green,
fading, and some of the red-topped trees.
(2) Piling and Burning.
Cutting infested trees, piling the stems and
thoroughly burning the bark surface may be used to suppress unmerchantable or inaccessible
southern pine beetle infestations. The entire bark surface of infested trees must be
thoroughly burned to insure effective control.
(3) Chemical Control - Use Only as a
Last Resort.
For chemical to use contact a forester who is a
Certified Pesticide Applicator.
Spray only spots that are inaccessible to
salvage. Cut and buck all infested trees into workable lengths. Wet entire bark surface
thoroughly (to the point of runoff) with a coarse spray from a low-pressure sprayer. Turn
logs two or three times to insure all surface is wet.
Spray infested stumps or trees damaged by
salvage crew. Cut and spray unmerchantable infested trees. Fell infested trees toward the
center of the spot. Spray tops only if they are infested. Never spray trees from which
beetle has emerged. This allows natural enemies to complete their development.
HABITS: The adult beetles are usually attracted
to weakened trees. In epidemics, however, they attack trees that appear to be healthy and
vigorous. Initial beetle attacks are in the mid-trunk area and then up and down the length
of the tree. The adult beetles bore through the bark and then excavate long winding
"S" shaped galleries. Eggs are laid in niches along these galleries. The larvae
feed in the cambium area until they are grown and then excavate cells in which to pupate
near the bark surface. After pupation the adult beetles chew through the bark and emerge.
The complete life cycle of the attack, takes from 25 to 40 days to complete, depending on
the temperature.
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