Quote:
Originally Posted by SBR Richard
i sure as hell hope that tree isn't dead due to pine beetle  |
How can I tell the difference between drought stress and bark beetle infestation?
Bark beetle infested tree foliage turns straw-colored in at least one section of the tree or quite often the whole tree. Pitch tubes are often present on attacked trees and appear as white or red pieces of sap on the outside of the tree. Some suggest this appearance is as if the tree is attacked by bubblegum. Only a few of these in the top of a tree need to be present and often binoculars help find the pitch tubes.
What Tree species are susceptible to the Bark Beetle?
Western Pine beetles attack Ponderosa and Coulter pine and have the most aggressive response to drought because of their ability to reproduce several times per year. Large populations growing in stressed trees can then attack even healthy trees and overwhelm them.
Jeffrey Pine beetle attacks Jeffrey pine and does not reproduce as fast as Western Pine beetle. It is present and effective in killing Jeffrey pine but not as epidemic as Western Pine Beetle.
Other insects such as Fir engraver and Ips beetles take advantage of stressed trees and can cause mortality as well.
Drought causes stress in trees and other agents such as root diseases can also come in and make it appear as if trees are dying of thirst when they are actually being attacked by other causes.
Why are the pine trees dying?
The trees are weakened by lack of water and produce less sap than a healthy tree. Sap forms the tree's natural defense system, leaving it unable to reject a beetle attack. The beetles are able to bore into the tree, laying their eggs. When the larvae hatch, they feed underneath the bark, cutting off water flow. During warm weather the beetles reproduce in extremely large numbers, allowing them to kill the trees quickly.