We have completed the 2006 Southern Pine Beetle (SPB) pheromone trapping. The results of this survey are below. A survey of losses from an ice storm that occurred in December 2005 is also included.
A total of 31 S.C. counties were trapped for SPB in 2006 using protocol devised by Billings, et al. This protocol includes monitoring 3 pheromone traps in each county for a 28-day period during early spring. Insects captured in each trap are returned to the laboratory for analysis. The total number of SPB for each trap is determined as well as the percentage of SPB to clerid beetles. Since clerid beetles are major predators of SPB, the percentage of them trapped is factored into insect population projections. Based on this trapping, a population prediction trend is determined for each county. In the past, such surveys have had a success rate of over 80% in predicting the degree of SPB infestation during the following summer. Last year we predicted that significant losses could occur in 5 counties. Although we had beetle activity in three of the five counties, it was at a low level and the SPB outbreak in South Carolina was declared over.
Of the counties trapped this year, none are predicted to experience a severe Southern Pine Beetle outbreak. This is the same prediction as last year. Additionally, only Edgefield and McCormick Counties trapped sufficient beetles in all traps to receive a prediction of increasing – high pine mortality. In Abbeville County we can expect a few scattered beetle spots. The other 28 counties we sampled had few beetles trapped and are not expected to have widespread problems. These counties include Anderson, Beaufort, Berkeley, Charleston, Cherokee, Chester, Colleton, Dorchester, Fairfield, Georgetown, Greenville, Greenwood, Hampton, Horry, Jasper, Kershaw, Lancaster, Laurens, Lexington, Newberry, Oconee, Pickens, Richland, Saluda, Spartanburg, Union, Williamsburg and York. This trapping information is presented in tabular and graphical form later in this report.
Statewide, the number of Southern Pine Beetles trapped was about 2/3 of last year’s total and the number of clerids dropped by 15%. This clerid population is still fairly high and should constrain SPB development in most areas, including those with some predicted beetle activity.
In the piedmont, Abbeville, Edgefield and McCormick have experienced some level of SPB activity for the last seven years. This is a high number of years of chronic beetle activity and we expect the clerids to hold the SPB level down. Beetle spots that occur should spread slowly and be fairly easy to control. However, if we enter another drought cycle, that stress could lead to more aggressive beetle activity.
In the coastal plains, we trapped very few beetles. The activity we anticipated last year failed to materialize and the low trap levels of this year indicate unfavorable conditions for SPB development. Historically, outbreaks in the coastal plain occur shortly after climatological changes. The change is usually from drought to excess soil moisture. This pattern of precipitation has occurred during the last two years, and some pines have been dying. However, the culprits have been either Black Turpentine beetles or Ips engraver beetles.
These trapping data results are for entire counties and there is always the possibility of sporadic and localized beetle activity in counties with overall predictions of low population levels. Activity is most likely in susceptible pine stands which are overstocked, overmature or stagnant, have poor drainage or have littleleaf, annosus or other root diseases present and causing stress.
We will be conducting aerial surveys in all South Carolina counties this summer. In the unlikely event of significant beetle activity, we will fly 100% surveys and notify affected landowners that beetle spots are present on their properties.
As mentioned above, Ips and Black Turpentine Beetles continue to cause mortality in overstocked stands and in areas where excessive rainfall coupled with impermeable hardpan caused some drowning of roots. A summer drought was also responsible for some stress that led to attack by these less aggressive beetles. Since these insects require different control tactics than SPB, it is important to determine which insect is causing each infestation. Ips beetles can be identified by their galleries that are usually H or I shaped rather than the winding galleries of southern pine beetles. Adult Ips beetles also eject the frass from their galleries while the SPB packs its galleries with frass. Black Turpentine Beetles attack the basal portions of the trunk and are a much slower killer than SPB or Ips. We can assist with this identification or provide training where needed. Last summer we evaluated multiple stands that were harvested due to such activity.
In summary, most of South Carolina can expect a year of no to minimal loss to southern pine beetle and related bark beetles. However, Abbeville, Edgefield and McCormick Counties may be poised for some degree of loss, especially if we have additional stress factors. Control by commercial salvage is effective in stopping any of the bark beetles infesting pines. Another possibility for control of Southern Pine Beetle only is the cut and leave technique. In this control strategy, infested trees and a buffer of apparently uninfested pines are cut but not necessarily salvaged. This method works best from May – October due to high daytime temperatures and SPB biological factors. This is not effective for Ips or BTB spots since those insects breed and mature easily in cut pines or stumps.
It is difficult to predict the degree of loss to SPB since environmental factors affect this. However, our best guess for S.C. for 2006 is for a loss of less than one million dollars. As usual, a hot summer with extended temperatures over 100 degrees Fahrenheit should constrain SPB development.
Another ice storm occurred in December 2005, although it caused nowhere near the losses of the storm of January 2004. Forestry Commission aerial surveys detected $259,193 in damage to pine and hardwood pulpwood and sawtimber in five South Carolina counties. These were Anderson, Greenville, Laurens, Pickens and Spartanburg. A listing of loss by county is included for your records.
Please contact us if you have any questions or if we can provide additional information.
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