Pine bark beetles are part of the ponderosa pine forest ecosystem. They have been killing weakened trees for eons. Persistent periods of drought and warmer temperatures can cause beetles to kill millions of trees. Bark beetles killed millions of trees in northern Arizona during the 2002 and 2003 drought.
Last year was one of the driest years since Flagstaff and northern Arizona, and conditions haven’t improved much. Homeowners with pine trees on their property should prepare for this potential threat, especially their high quality and most majestic trees.
Help your trees fight off attacks by bark beetles with preventative measures. One of the best, albeit costly, ways is to reduce the number of trees on your property by thinning them out. Fewer trees lead to less competition for limited moisture.
A fallen tree attracts beetles. Either remove the material immediately or shatter it. Keep the piles in the sun and as far away from living trees as possible. Logs can be stacked and covered with plastic for several days to kill bugs in the wood.
Healthy trees can also be protected by deep irrigation. Water should be applied around the drip line or the outer edge of the tree canopy. Use a waterer hose to slowly drip water into the ground to a depth of about 2 feet.
Trees that are not infested can be protected from beetle attacks by spraying them with insecticides. There are some products that are labeled to protect the ponderosa from being attacked by bark beetles. Labeled pesticides contain the active ingredients carbaryl or permethrin. Suitable products are long-lasting, one application per year is enough and they are sprayed on the entire trunk of the tree. A licensed arborist or pest control applicator is recommended for spraying. Typical home and garden products that contain carbaryl or permethrin are not effective enough.
