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Southern Pine Beetle

The southern pine beetle (Dendroctonus frontalis) is the most destructive forest insect in the South. Weakening of trees by flooding, windstorms, and especially drought commonly precede outbreaks.

Southern Pine Beetle (Dendroctonus frontalis),
Courtesy of USDA Forest Service, Bugwood.org

If you are a landowner concerned about Southern Pine Beetles on your property, please visit the Southern Pine Beetle Prevention Program.

Host

Prefer loblolly, shortleaf, Virginia, pond and pitch pine

Identification

The brown to black beetle is about 1/8 inch long. Its hind end is rounded, in contrast to the scooped out posterior of the IPS beetle. Larvae are white with a reddish-brown head and the pupae pure white. Fully-grown larvae and pupae are approximately 1/8 inch in length. Eggs are white and easily visible to the eye.

Signs of Attack

Southern pine beetle forest infestation,
Courtesy USDA Forest Service, Bugwood.org

The first indication of attack is usually yellowing or browning of needles. The trunk will usually reveal white, yellow, or sometimes red-brown pitch tubes, about as large as a wad of gum.

Southern pine beetle pitch tubes on a loblolly pine,
Courtesy Erich G. Vallery, USDA Forest Service, Bugwood.org

Under drought conditions, pitch tubes may be very small or absent, and only reddish-brown boring dust will be present. Removal of the bark will show a distinctive winding “S” shaped gallery pattern.

This pattern is quite different from the “Y” or “H” shaped gallery patterns of the Ips beetle and is a good identification characteristic. In active spots, trees in the center have dark reddish-brown foliage. Foliage will change to light greenish or yellowish-green on the edges of active spots.

Life Cycle

Multiple life stages of the Southern Pine Beetle (Dendroctonus frontalis),
Courtesy of USDA Forest Service, Bugwood.org

The southern pine beetle has a complete metamorphosis consisting of the egg, larval, pupal, and adult stages. The complete life cycle of the attack, which takes from 25 to 40 days to complete, depends on the temperature. The beetle may produce as many as nine generations per year.

Habits

The adult beetles are usually attracted to weakened trees. In epidemics, however, they attack trees that appear to be healthy and vigorous. Initial beetle attacks are in the mid-trunk area and then up and down the length of the tree. The adult beetles bore through the bark and then excavate long winding “S” shaped galleries.

SPB larve feeding in the galleries

SPB lay eggs in niches along these galleries. The larvae feed in the cambium area until they are grown and then excavate cells in which to pupate near the bark surface. After pupation, the adult beetles chew through the bark and emerge.

Control

Natural enemies, such as diseases, parasites, predators and weather, help maintain beetle populations at low levels and bring cyclic outbreaks under control.

Integrated pest management may be achieved through any one or all of the following suppression techniques:

  • Rapid salvage and utilization of infested trees
  • Piling and burning of infested materials
  • Chemical control in high-value resources
  • Cut-and-leave (May through October)

To select the most appropriate strategy, the user is referred to the Integrated Pest Management Decision Key (IPM-DK). Good forest management is the most effective method of preventing losses from the southern pine beetle.

Activity Map

The Mississippi Forestry Commission completes two Forest Health flights per year, usually in the spring and fall.

The interactive Private Lands Forest Health Update map shows all of the points that found damage during these flights. The map also includes damage from wind and the IPS engraver beetle.

We encourage Private forest landowners who are concerned about possible Southern Pine Beetle (SPB) activity on their property to contact their local MFC Forester.