A Methodology for Assessing Annual Risk of Southern Pine Beetle Outbreaks across the Southern Region Using Pheromone Traps

Ronald F. Billings and William Upton

Texas Forest Service

A practical and reliable system to forecast population trends and infestation levels of the southern pine beetle (SPB), Dendroctonus frontalis, has been implemented throughout the range of this forest pest in the southern United States.  The South-wide SPB Prediction System, developed by the Texas Forest Service (TFS), involves monitoring numbers of southern pine beetles and those of a major predator of SPB (the clerid beetle, Thanasimus dubius).  In general, three Lindgren funnel traps baited with the SPB aggregation pheromone frontalin and a rapid release container of pine turpentine are placed in each county or National Forest to be surveyed.  The traps are monitored for four consecutive weeks during the spring (when dogwood trees bloom).  This physiological event coincides with the long-range dispersal of SPB.  Responding insects are collected weekly.  The average number of SPB/trap/day and the ratio of SPB to clerids are the variables used for predicting infestation trends for the remainder of the year.  Since its initiation, the system has proven to be a practical and reasonably accurate means for forecasting SPB population trends (increasing, declining or static) and expected infestation levels (low, moderate, high or outbreak) throughout the pest’s range in the southern United States.  Results from trapping surveys received from numerous state and federal cooperators in 15 states are compiled by TFS entomologists and predictions are delivered to the public via the Internet.  Predictions, validated by subsequent infestation detection records, have proven accurate ca. 70-80% of the time.  Forest managers have come to depend on this early warning system to predict pending outbreaks or collapses of SPB populations.  This represents the first effective prediction system for bark beetle outbreaks anywhere in the world.  Predictions can be incorporated into area-wide hazard maps to generate up-to-date risk maps for a particular national forest, county, state or region.

Native Pests Session - Wednesday Afternoon

corresponding author:

Ronald F. Billings
Texas Forest Service
301 Tarrow, Suite 364
College Station, TX 77840-7896
979-458-6650
rbillings@tfs.tamu.edu