Spruce Bark Beetle Infestation
dstaples at livingston.net
Fri Dec 27 17:40:41 EST 1996
Harry J. Donahue wrote:
> I am located in South Central Alaska near Anchorage. Over the past few
> years, I have lost over 50 of my largest spruce trees. I have been
> spraying with Sevin(Carbaryl) up to 20 feet. Is there a life cycle for
> these insects, or am I forced to spray on an annual basis forever???Any
> suggestions would be very much appreciated.
> Harry Donahue E Mail HJD at aonline.com
Ips engravers usually are the commonest inner bark borers in most pine and
spruce forests. They are not as agressive as species of Dendroctonus, for they usually
infest only dying trees, severely injured trees, or green slash. Sometimes, however,
epidemics develop during which many living trees are killed. Frequently these tree
killing beetle populations develop in trees weakened by drought, fire, windstorm, or in
the larger slash, green bolts or logs left in the woods...................
Prventative control methods consist of managing forests so that the trees are
kept growing well. When pulpwood is cut the remaining slash usually is so small that it
dries rapidly and few beetles mature. With sawlog operations, however, the larger slash
produced is more suitable breeding material, and large populationss may be produced.
End of quote.
Every thing I read says damaged stems or large slash. Perhaps not on your property, but
on a neighbors. Also, Sevin may not be persistant enough to cover the beetle life
cycle. You may want to go to benzene hexacholoride or one of the more persistant, and
time it for when new adults leave the bark (mid spring?). Other than that, stand
I am from Texas, and reading from the book, so look to one of the cold weather foresters
to fine tune your control effort.
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