Actual SPB Infestation Levels: 1987 to 2005

Fig. 1 - Total numbers of southern pine
beetle infestations

Total numbers of SPB spots detected in 16 States in the Southeastern United States for the period 1987-2005 are shown in Figure 1. Infestation levels on a regional basis varied significantly by year from a high of >90,000 spots in 2002 to a low of <5,000 spots in 2005. During the 12-year interval from 1987 to 1998, at least one SPB outbreak cycle (increasing, peak, declining) occurred in every participating State. SPB populations reached peak levels in Arkansas in 1995; in Texas in 1989 and 1992; in Louisiana in 1992; in Mississippi in 1988, 1991, and 1995; in Alabama in 1992 and 1995; in Georgia in 1988; in Tennessee in 1988; in Virginia in 1993; in Florida in 1995 and 1997; in South Carolina in 1995; in North Carolina in 1995; and in Maryland in 1993. Interestingly, 9 of the 11 States that had participated in the system since 1987 reported SPB infestations in every year from 1987 to 1998. Only Florida and Maryland had at least 1 year with 0 SPB spots during this time period.

Fig. 2 - Southern pine beetle prediction chart.

From 1999 to 2005, SPB activity fluctuated widely across the South. SPB infestations totally disappeared west of the Mississippi River: Louisiana, Texas, Arkansas, and Oklahoma reported 0 spots for these years and few if any SPB were captured in pheromone traps during this 7-year period. In sharp contrast, the worst SPB outbreak on record within a single State occurred in South Carolina in 2002, when 67,127 SPB spots were detected (> 14 spots per 1,000 acres of host type). Peak populations occurred in Alabama and Virginia in 2000; in Kentucky, Tennessee, and Florida in 2001; and in Georgia, North Carolina, and New Jersey in 2002. Throughout this period, SPB trapping procedures were standardized with all cooperators using the same turpentine (Hercules™) and dispenser (amber bottle and wick). Also, in 1998 and again in 2002, the SPB prediction chart was slightly modified based on results of pheromone trapping and SPB detection records for the period 1987-2001 [see Figure 2 versus the chart shown in Billings (1988)]. Accordingly, in certain cases, results for the period 1987-1998 were evaluated separately from those for the period 1999-2005 to determine whether accuracy of the prediction system has improved since 1999 following standardization of field trapping procedures and modifications to the SPB prediction chart.

Next: Overall Prediction Accuracy

Click to view citations... Literature Cited

• Billings, R.F. 1988. Forecasting southern pine beetle infestation trends with pheromone traps. In: Saarenmaa, H. Integrated control of Scolytid bark beetles. International Congress of Entomology. At: Vancouver, B.C., Canada.