2012 Southern Pine Beetle Forecast for Florida
The 2012 Florida survey was conducted using from one to three traps (Lindgren funnel traps baited with alpha- and beta-pinene and the primary SPB aggregation pheromone frontalin) in each of 26 counties, with each trap located in a different stand of susceptible forest type. The 26 counties surveyed included those that are most likely to experience Southern Pine Beetle (SPB) problems based on historical outbreaks and/or their relative abundance of loblolly pines. As in previous years, effort was made to place traps in stands containing sawtimber size loblolly pine or areas where loblolly pine is most abundant. Traps were distanced at least 40 feet from any pine tree and checked weekly by FFS foresters in March. Numbers of SPBs and their clerid beetle predators (Thanasimus dubius) were counted for each of the four weekly collections per trap. Numbers of SPB/trap/day and the %SPB were then applied to the Modified SPB Prediction Chart model (Ron Billings, Texas Forest Service) to provide a forecasted level of SPB activity for the remainder of the year. Forecasted activity was based on a relative scale of Low, Moderate, High, or Outbreak.
2012 Trapping Results and Discussion
The 2012 survey results suggest that SPB populations will remain low at all but one trap location in the 26 counties surveyed across northern and central Florida (Figure 1). Both the total number of SPB/trap/day and %SPB remained static and relatively unchanged from 2011 (Table 1). This suggests that the generally low levels of SPB activity that the state has experienced since 2003 will continue.
St. Johns County was shown to fall into a higher “moderate” class for forecasted SPB activity. In 2011 St. Johns was one of two counties where SPB activity was detected, with a 60 acre spot that had grown in size from ten acres the previous year on an adjacent residential (HOA) conservation easement property. This particular spot was contained by harvesting the infested trees in addition to applying a 100 foot buffer around adjacent timber. Special attention and monitoring will be applied to St. Johns County this year during the summer SPB aerial surveys.
As in previous years, all counties in FFS Districts/Centers 1-12 will be asked to conduct an initial aerial SPB detection survey.
Because of limited survey inputs, a vast resource of potential habitat, and the limitations of the predictive model, the forecast presented here cannot be expected to be 100% accurate. Low/Static SPB predictions do not guarantee that troublesome infestations will not develop on a local or limited basis in some counties. Activity predictions are likely to be more accurate for the 5-mile radius region around each trap than for the county as a whole. Given the limitations of the forecast, the recent drought and/or flooding experienced by some areas in the state, and the potential for environmental conditions to change after the survey, areas of suspicious pine mortality should be promptly inspected for evidence of SPB in the coming months.
Sincere thanks to all the foresters who were involved in installing traps, making weekly collections, and submitting jars for sample processing.
Authors: Christopher Pearce, Survey Coordinator, and
Jeffrey Eickwort, Forest Biologist
Florida Forest Service