MANAGE FORESTS & LAND

  • FOREST HEALTH: SOUTHERN PINE BEETLE CONTROL METHODS: CUT & LEAVE

    Infestations of the southern pine beetle in East Texas can be treated by a method known as cut-and-leave to reduce losses from infestation (spot) growth and new spot proliferation.

    Texas A&M Forest Service recommends application of the cut-and-leave procedure in situations where prompt salvage or other control alternatives are not feasible. The method is designed to disrupt spot growth in small- to medium-sized spots by dispersing emerging beetles during the season (summer) when they are least likely to survive, fly long distances and establish new infestations. Also, survival of developing broods in felled trees may be reduced. The treatment is simple, inexpensive and requires a minimum of manpower, equipment and training.
     + How to Apply
    1. Identify, the currently infested (active) trees within the spot (the most recently attacked trees in an expanding infestation will have green foliage as well as pitch tubes and/or boring dust in bark crevices).

      Cut and Leave - Figure 1  
    2. Fall all active trees toward the center of the spot.

      Cut and Leave - Figure 2  
    3. Fall a horseshoe-shaped buffer of green, uninfested trees around the active head of the spot and leave them lying on the ground with crowns pointed toward the center of the spot. For small- to medium-sized spots (100 currently infested trees), the buffer should be as wide as the average height of the trees in the spot (40’-60’ wide). The buffer may need to be wider for large, rapidly expanding infestations.
    4. Old dead trees with no bark beetles remaining should be left standing to allow development of parasites and predators that help control bark beetle populations.
    5. If possible, check the treated spot after two weeks for re-infestations (breakouts) around the boundary. Re-treat all breakouts.

    The buffer strip of green trees must be included to assure effective control, particularly for spots treated during warm months.

     + When to Apply
    Cut-and-leave treatment may be applied at any time of the year. However, the treatment appears most successful when applied during the summer months to spots with 10-100 active trees. Infestationswith more than 100 active trees can be treated with cut-and-leave, but may require a wider buffer.

    Prompt treatment after detection is recommended because experience has shown that large spots (100+ active trees) are difficult to control regardless of the treatment applied. On the other hand, spots with less than 10 active trees often are soon abandoned by the beetles and may require no treatment.
     + Glossary of Terms
    Active Head of Spot: Portion of the spot containing beetles in the process of attacking green trees.

    Active Tree: Pine tree containing attacking adults or bark beetle broods (eggs, larvae, pupae, or new adult beetles).

    Buffer: Group of green, uninfested pines adjacent to the most recently infested trees in a spot. Both the buffer and the active trees are felled to assure disruption of spot growth and dispersion of beetle populations.

    Southern Pine Beetle (SPB): Dendroctonus frontalis (Coleoptera: Curculionidae), a bark beetle that can be identified by the S-shaped trails it makes beneath the bark of attacked trees.

    Spot: Group of dead or dying pine trees infested by the southern pine beetle.

    Spot Breakout: Infestation of green trees on the outer edge of a spot following a control treatment.

    Spot Growth: Natural expansion of untreated spots as additional green trees on the outer edge of a spot become infested.

    Spot Proliferation: One or more spots initiated by beetles escaping from controlled and/or uncontrolled spots, located at some distance from the immediate edge of the initial spot.
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