1456
Piñon pine "pitch mass" borer

The piñon pitch mass borer is a serious pest of piñon trees in landscapes throughout much of Colorado. Though piñon is the main host, ponderosa and possibly Scotch and Austrian pines may occasionally be infested.

Larvae tunnel into the tree's water conducting vessels, causing large quantities of pinkish pitch to ooze from their entry hole. Damage disfigures large branches and trunks and weakens the tree. Heavily infested branches may even break.

Like most borers, the pitch mass borer takes advantage of already weakened trees. In landscapes, over watering and over crowding can stress piñons, making them susceptible to an attack. Adjusting irrigation schedules and thinning over crowded areas are the most important control of this borer.

You may try to kill individual borers by inserting a flexible wire into their tunnels; however, larvae can be difficult to find because they often tunnel for several inches under the bark.

Preventative trunk sprays can reduce attacks. Permethrin sprayed heavily on tree trunks and major branches during the June to August flight period of the adult moth helps prevent additional boring. Two or more treatments per season should be repeated for at least two years on infected trees.

For more information, see the following Colorado State Extension fact sheet(s).

• Pine Tip Moths
• Shade Tree Borers

For more information, see the following Planttalk Colorado™ script(s).

• Pinon