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Life Cycle
Protruding Pine Sap Enclosing Beetle
Forest Infestation
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Photo credits: Ronald F. Billings,
Texas Forest Service, Bugwood.org

Southern Pine BeetleHOST:  Prefer loblolly, shortleaf, Virginia, pond and pitch pine
 
IMPORTANCE: 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 precedes outbreaks.

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: 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. 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: Adult beetles are usually attracted to weakened trees. In epidemics, they attack trees that appear healthy and vigorous. Initial attacks are in the mid-trunk and then the length of the tree. Adult beetles bore through the bark and excavate long winding "S" shaped galleries. Eggs are laid in niches along the galleries. Larvae feed in the cambium until grown, and then excavate cells near the bark surface in which to pupate. After pupation, adult beetles chew through the bark and emerge. The complete cycle of the attack takes from 25 to 40 days, depending on the temperature.
 

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. Eggs are laid 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. The complete life cycle of the attack, takes from 25 to 40 days to complete, depending on the temperature.

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, and 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.

Go to SPB Prevention Program

Additional Resources:
Southern Pine Beetle Hazard Maps