Linda Joyce
Rocky Mountain Research Station 240 West Prospect
Fort Collins, CO 80526
Phone: 970-498-2560 ljoyce@fs.fed.us
Pine Beetle Evidence
Discolored
foliage in late Spring is a sign that ponderosa and lodgepole pine
trees have been killed by the mountain pine beetle. These trees
are called 'faders' and/or 'flag trees' (slide credited to Jose
Negron).
Reddish
pitchtubes (resin mixed with frass), on the tree trunk and reddish
boring dust at the base and also in the bark crevices of the tree,
are good indicators of a successful beetle attack (slide credited
to Jose Negron).
Unsuccessful
beetle attacks are identified by large white pitch tubes on the
tree trunk. These resin tubes may have an embedded adult beetle.
Coarse frass can be found at the base of the tree. No blue-stain
is present and the foliage is green.
Woodpecker
damage on beetle infested trees is very noticeable. They make
individual holes in the bark as they search for and feed on beetle
larvae. Woodpeckers will pick out the best brood producing tree
and therefore are good indicators of beetle attacks (slide
credited to Jose Negron).
The
sapwood of an infested tree will be discolored by a blue staining
fungi; the heartwood will not be stained.
Exit
and entrance holes are evident on the bark. Entrance holes will be
visible during the attack period and exit holes will appear the
following emergence period (slide credited to Jose Negron).
