Pine shoot beetle (Tomicus piniperda) is a non-native pest of pine trees in Wisconsin. It is native to Europe, North Africa, and Asia. The pine shoot beetle threatens Wisconsin's Christmas tree industry.
Pine shoot beetles, or PSB, are in the family Curculionidae, subfamily Scolytinae. Wisconsin is part of a federal quarantine that also includes other states in the Midwest and on the East Coast.
Adult pine shoot beetles emerge early in the spring and tunnel beneath the bark of pine logs, stumps or unhealthy trees to mate and lay eggs. Once larvae hatch, they feed on the inner bark and cambium of the main stem of recently killed, cut or dying pines. They pupate in May and June, and emerge as adults to feed on new shoots of pines. Adults commonly feed on the pith inside of shoots on newer growth close to the terminal bud, completely hollowing out the shoots.
Adults overwinter by tunneling into the bark at the bottom of the tree trunk or on dead materials such as logs and stumps and emerge the following spring. Pine shoot beetles may also introduce blue stain fungi into pines.
Removing slash and stumps that may contain PSB adults and larvae is a proactive way of managing this pest.
In general order of host preference, PSB feeds on:
- Scotch pine (Pinus sylvestris)
- Austrian pine (Pinus nigra)
- Eastern white pine (Pinus strobus)
- Red pine (Pinus resinosa)
- Ponderosa pine (Pinus ponderosa)
Wind and human movement of infested items are the most common means by which pine shoot beetles spread to new areas.
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