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Southern Pine Beetle
2007 Southern Pine Beetle Forecast for Florida
The 2007 Florida survey was conducted using one or two traps (Lindgren funnel traps baited with turpentine 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 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 DOF foresters from in March and April. Numbers of SPBs and their clerid beetle predators (Thanasimus dubius) are counted for each of the four weekly collections per trap. Numbers of SPB/trap/day and the %SPB are 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 is based on a relative scale of Low, Moderate, High, or Outbreak.
2007 Trapping Results and Discussion
The 2007 results suggest that SPB populations remain at low levels in all surveyed counties across northern Florida. Of the 33 traps deployed statewide, none caught sufficient numbers of SPBs to warrant predictions above a “low” level of SPB activity for the coming year (Fig. 1). The total %SPB figure increased slightly from 2006 (Table 1). The %SPB is an expression of the number of SPBs relative to the number of clerid predators; “50% SPB” would indicate equal numbers of SPBs and clerids trapped. However, given the very low numbers of both SPB and clerids that were trapped, this small increase in %SPB does not affect the activity level prediction.
As in previous years, all counties in DOF Districts/Centers 1-12 have been asked to conduct an initial aerial SPB detection survey. Procedural guidelines for aerial surveys, ground checking, and reporting are available to Division of Forestry foresters. Confirmed SPB spots should be controlled as quickly as possible, preferably through cut-and-remove techniques. See links to SPB control information.
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. Due to delays in receiving some materials, the trapping was conducted about 2 weeks later than usual, and it is uncertain what effect (if any) this may have had on the results. Given the limitations of the forecast, the potential for environmental conditions to change after the survey, the relatively warm previous winter, and drought conditions in much of the state, 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: Jeffrey Eickwort, Forester, and Bud Mayfield, Forest Entomologist
Florida DACS Division of Forestry
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