January 18, 2014

1 - There are several beetles that can infest firewood, some may be a threat to landscape trees.

Yard and Garden January 18, 2014

I just had a cord of Ponderosa firewood delivered. The wood was infested with bark beetles. The trees were cut in the summer, cured, and delivered January 4th. I am burning the wood and should have it all burned by March at the latest.

Are the pinions around my house vulnerable in any way? Either to beetle infestation (I can't see how), or by the blue staining fungus spore?


Via NMSU University-Wide Extension


Are you sure that the beetles are bark beetles? Is it possible that they are wood borers, or twig beetles? The type of beetles makes a difference. Some bark beetles attack ponderosa pines while other types of bark beetles attack piñon trees. Some species of bark beetles will attack both. Bark beetles may cause infections by various microorganisms and some bark beetles have specialized pockets for carrying these microoganisms. The blue stain fungus is one such disease and an important factor in killing trees.

Wood borers generally attack trees recently cut or dying trees. This may be trees that have been cut and allowed to remain in the forest. Based on your description of the fire wood, with summer cutting and the curing process, borers are the most likely culprits. Wood borer can do significant damage to the wood, but are unlikely to move to healthy piñon trees. However, the term "healthy" may be a deceptive word in New Mexico, especially after last year's drought early in the year. Apparently healthy trees may be stressed and attractive to the bores and other beetles.

Twig beetles are small beetles that usually attack twigs, but may sometimes invade and feed on trunk tissue, killing a tree. Identifying the beetle is important. Your local NMSU Extension office can help you identify the beetles in your firewood.

To be safe, or if the beetle proves to be one that can attack your piñon trees, you can provide some protection for the trees by enclosing the wood in clear plastic covers. Place these wood pile in 4x4x4 piles (half cord) in sunlight, and then cover the wood with clear plastic (not black or other colors), and seal the base of the plastic with soil. This will enclose any beetles so that they cannot escape to infest your piñon trees. The reason you should use clear plastic is to create a greenhouse effect causing heat to accumulate under the plastic. Colored plastic will not work effectively. In the winter, there may not be enough heat accumulated to kill all the beetles, but some at the top of the plastic may be exposed to enough heat to die and the plastic will confine any beetles that survive to prevent infestations in nearby trees. The beetles will die and your piñon trees will be safe if the temperature under the plastic reaches 160 degrees during the summer (or on warm days).

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!