One major problem with that species of plant is improper pruning. People
who do not understand pruning targets often hurt the trees and claim to be
pollarding. Pollarding done correctly is very good form. Done incorrectly
causes many problems. The beetles may well just be secondary agents. can
you post some pictures of your plants to a web site?

Many tree problems are associated with the following: They are Case
Sensitive.

Troubles in the Rhizosphere
http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

Unhealthy Trees from the Nursery / Improper Planting
http://home.ccil.org/~treeman/sub1.html
and
Look up "Tree Planting" http://www.treedictionary.com

Improper Mulching - http://home.ccil.org/~treeman/sub3.html
and
http://www.treedictionary.com/DICT2003/M/ Look up "Mulch"

Improper Pruning
http://www.treedictionary.com/DICT2003/tree_pruning

Improper Fertilization (See A Touch of Chemistry)
http://www.treedictionary.com/DICT2003/shigo/CHEM.html

Tree Farming and Related Problems
http://www.treedictionary.com/DICT2003/SOUND/

Sincerely,
John A. Keslick, Jr.
Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.

"Phisherman" wrote in message
...
I've always wanted a red Crepe Myrtle tree/shrub. But, now I'm
seeing evidence of the ambrosia beetle attacking crepe myrtles on my
neighbor's property and the city park. There is what looks like
sawdust pieces on the lower trunk. What can be done about this? Are
there varieties of crepe myrtle resistant to the ambrosia beetle? I'm
in e.TN.