A Method for Controlling Southern Pine Beetle Infestations
The Southern Pine Beetle
The Southern Pine Beetle (SPB) is the most destructive pine bark beetle in the South. SPB infestations commonly originate in poorly managed or overstocked stands. Once underway, outbreaks can spread rapidly, killing trees over hundreds of acres, and move into managed stands.
SPB infestations can be identified in several ways. The most obvious symptom is the change in the needles of the tree crown from green to yellowish to reddish brown. Other symptoms are listed in the table below. For more information on identification and the life cycle of the SPB, see Forestry Leaflet No. 5, Identifying the Southern Pine Beetle.
|Foliage||Pitch Tubes||Bark||Exit Holes||Ambrosia
|Freshly Infested||Green||Soft, white,
|Infested With Developing Brood||Green trees with larvae; fade to yellow before brood emerges||White,
|Few, associated with attacking adult reemergence||White, localized areas around base of trees|
|Red, needles falling||Hard, yellow, crumbles easily||Very loose,
base of trees
Initial infestation is followed by the development of a "spot." The spot usually spreads in one direction as new trees are attacked in an area called the "active head." (see Figure 1)
The risk of SPB infestations can be reduced by practicing
proper forest management. However, when infestations (spots) do occur, direct control
tactics are needed to minimize timber losses.
Salvage removal is the preferred control method since infested trees are removed and utilized, giving the landowner some financial return. For salvage to be effective, SPB infested trees must be removed very quickly. An adequate buffer strip of uninfested green trees must also be cut around the active head(s) or spreading edge(s) of the spot.
When to Apply Salvage Removal
Salvage may be applied at any time of the year when ground conditions permit. Prompt treatment after spot detection will minimize additional timber loss from spot growth. When salvage of a spot is not feasible or must be delayed for long periods, active infestations should be treated by the cut-and-leave method. (See Forestry Leaflet No. 7, Cut-and-Leave)
How to Apply Salvage Removal
The buffer strip of green trees must be included to assure effective control. If salvage operations are delayed, active spots may have to be marked again before harvesting to account for additional spot growth.
Financial Return from Salvage Removal
The financial return from the salvage of SPB-infested timber will vary according to several factors. These include the total volume and size of the trees, their current market value, the accessibility of the spot, and the type of harvesting equipment used. After the trees within the marked boundaries of a SPB spot have been harvested, additional uninfested trees may be selectively thinned from the adjacent stand, if needed, to complete the final load or increase the total volume to improve the price received.
Glossary of Terms
ACTIVE HEAD(S) OF SPOT - Area(s) of the spot containing beetles in the process of attacking green pines.
INFESTED TREE - A pine containing southern pine beetle broods (eggs, larvae, or pupae) or attacking adults.
BUFFER STRIP - A group of green, uninfested pines that are cut adjacent to the most recently infested trees in the spot.
SPOT - A group of dead or dying pine trees infested by the southern pine beetle.
SPOT BREAKOUT - An infestation of green pines on the outer edge of a spot following a control treatment.
Keeping your pine timber stands healthy and vigorous, and having a good knowledge of the southern pine beetle habits and symptoms is essential to effectively deal with this destructive pest. Professional advice and assistance is available through the South Carolina Forestry Commission, Clemson University Cooperative Extension Service, U.S.D.A. Forest Service, forest industry personnel, and private consulting foresters.