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.
- 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.
- 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.
- 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.