Southern pine beetles (SBPs) have the potential to ravage pine forests and decimate the investments of timber owners. What seems to start with one infested tree can quickly multiply into a big problem. Education about this species and new relief funding are key to protecting vulnerable natural resources.
Biology and Identification
Scientifically known as Dendroctonus frontalis, the southern pine beetle is a devastating insect that bores into pine trees– appropriately giving it its name.
“Unfortunately, pine beetles are a common problem in Alabama,” said Becky Barlow, Alabama Extension assistant director for agriculture, forestry and natural resources programs. “In general, there are three types of beetles that attack pines: SPBs, black turpentine beetles and ips beetles.”
SPBs are typically brown to black in color and feature a rounded body. According to Barlow, who is also an Alabama registered forester, the SPB is the most destructive of the three. Female SPBs bore through tree bark into the cambium of southern yellow pines (loblolly, longleaf, shortleaf and slash). Trees produce resin to push the insects out of these bore holes, forming pitch tubes.
“Pitch tubes may be seen on the tree trunk which can look like popcorn on the bark,” Barlow said. “Under the bark, you will see Sshaped galleries in the wood. As an early sign of stress from the attack, needles first turn yellow then brown. You may notice that trees attacked by SPBs are often killed in groups.”
Barlow said when first looking for signs of SPBs, timber owners and managers should look around the base of the tree for sawdust or pitch tubes. If necessary, pull back some bark near potential SPB tubes and observe the shape of the gallery. If it resembles an H or Y shape, it is a possible ips beetle problem. These beetles are typically found in recently felled trees and logging debris but may also attack standing trees.
The key to solving an SPB problem is proactive and active forest management. By consistently studying a timber stand, forest managers can catch the problem earlier and mitigate further spread of the issue. Barlow said after confirming SPB-infected trees, forest managers should immediately remove them from the site.
“Move harvested trees (tops and all) away from standing, healthy trees, especially in warm-season harvests,” she said.
The age of a timber stand also has an influence on SPB infestations. Trees have ample space apart when a timber stand is early in its life. This helps mitigate competition for resources such as light, water, soil and nutrients. Barlow said when trees start to grow larger and increase in diameter, competition increases. This may cause trees to become stressed, making them vulnerable to an insect attack.
“Thinning trees before this occurs can prevent this,” Barlow said. “Also, look at your forest soil. Planting the right tree on the right site is critical. Loblolly pine usually does not do well on shallow, rocky or sandy soils with low moisture and limited nutrients. In these cases, landowners may have more success if planting another species more suitable for the site, such as longleaf or shortleaf pine.”
When it comes to forest management, Barlow said she is reminded of a quote from Benjamin Franklin that applies: “An ounce of prevention is worth a pound of cure.”
For those who qualify, the Alabama Forestry Commission (AFC) is currently accepting applications for financial assistance for SPB prevention. The SPB Costshare Prevention Program is in effect, providing relief for many Alabama forest landowners. This program, through a grant from the United States Forest Service, will help implement forest management practices that reduce susceptibility to SPB damage.
“This cost-share program is all about prevention,” said Alabama State Forester Rick Oates. “The AFC is hoping to assist forest landowners in implementing forest management practices that will reduce future southern pine beetle damage on their property. That’s the ultimate objective.”
The agency said it is conducting annual SPB survey flights. This reconnaissance allows forest landowners to be notified of potential infestations before they can become an issue.
“Although we’re already seeing a slight increase over last year, we’re not expecting epidemic levels,” Oates special friend, Imone McDermott, and close friend Sandy Lyles Jr., along with a large community of other relatives and friends.