It’s quite visible. Sometimes you see it on television. Often it is printed in the newspaper. It’s no secret that two million acres of lodgepole pines have come under attack in the high country. You may be thinking – I live on the plains and don’t have lodgepole pines – so there’s no need for me to worry about my trees.
That’s not quite true; there are several accounts of mountain pine beetles attacking trees along the Front Range. In Fort Collins, 300 pines were attacked and 20 succumbed. From Denver northward through Wyoming and east into Nebraska there have been reports of mountain pine beetles attacking pines. Scotch or Scots pines are the most often infested. Austrian, eastern white, mugo and ponderosa pines are also challenged by beetles.
Once a pine tree has been successively attacked by beetles it will die. The operative word is “successful”. In the urban landscape, most mountain pine beetle attacks are not successful. In urbanized trees, typically what we see, the beetles are pitched out drown in resin. Urban trees are typically more vigorous and receive more water than their forested counterparts enabling them to fend off beetle infestations.
But that isn’t the end of the story. Once a tree is challenged, it is ripe for repeated attacks and at some point the beetles will successfully attack the tree. Mountain pine beetles produce scents called pheromones signaling additional beetles to come and bore into the tree. These are termed aggregation pheromones – signaling beetles to amass.
What should you do?
- Ensure your pines receive adequate water. Water is needed by the trees to produce the resin to pitch the beetles out.
- Few urban trees will come under beetle attack, but once beetles breach the tree’s defense barriers there is no going back – the tree will die. If there are trees which you wish to protect – no is a good time to contact a commercial tree care company and discuss preventive spraying.
- Preventive treatments with insecticides containing permethrin, bifenthrin, or carbaryl should be completed by May.
- Watch your trees during the summer. Look for popcorn sized pitch masses on the bark. If you see something suspicious – again contact a commercial tree care company.