The Survival of Mountain Pine Beetle in Unpeeled Logs

The mountain pine beetle (Dendroctonus ponderosae) is the most serious pest of ponderosa pine (Pinus ponderosa). Management of this insect involves indirect controls, reducing stand susceptibility, or direct controls, reducing the beetle population. One tactic for reducing bark beetle populations is to fell and treat infested trees in place. Treatments usually involve cutting the tree trunk into sections and covering the infested logs with plastic or coating in diesel oil and rotating them to kill the beetles. These treatments are not always practical due to labor intensity or environmental impact. A study was conducted to determine whether cutting infested trunks into short, 60- to 75-cm lengths, during autumn without further treatment would be sufficient to serve as a population reduction tactic. Groups of infested trees were felled in October 2006 and 2007 with the trunks cut into 60- to 75-cm lengths and left in place. Brood densities were determined in these sections and standing infested trees during the following March and June and emergence in September. Felling infested trees during autumn and cutting into short sections without rotating resulted in 21-24% beetle emergence compared to standing infested trees and may be a practical means of reducing the potential spread of localized beetle populations.