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Pine Engraver Beetle Numbers Increasing

FOR IMMEDIATE RELEASE: Wednesday, July 7, 2021

MEDIA CONTACT: Brian Walsh, Brian.Walsh@state.sd.us


Pine Engraver Beetle Numbers Increasing


PIERRE, S.D. – The pine engraver beetle is taking advantage of downed trees from the May tornado near Custer. Landowners are asked to take steps to help control population expansion.


“The downed trees are quickly becoming infested with the engraver beetles” says Greg Josten, South Dakota State Forester. “Once the beetle raises a new generation inside this fallen material, the new adult beetles will leave this wood and may attack standing live trees.”


Engraver beetles are native bark beetles producing two to three generations per year. If there is not fresh green slash available for the beetles, the summer generation of engraver beetle often moves from downed trees to live trees, especially during droughts. 


If possible, landowners should cut the limbs and branches of these downed trees into short lengths, about three feet long, and scatter them so the wood dries out before the adult beetles emerge. Logs should be salvaged, taken to a local sawmill, and debarked as soon as possible. Removal of the bark will destroy the beetles. Slabbing, the process of squaring a log which leaves the bark attached to the wood, does not kill the beetles.


Another option is to cut infested trunks into short lengths, two or three feet long, and cover them with 6-mil clear plastic. The plastic must be sealed to the ground at all edges. This solar treatment will heat up the wood and reduce the number of beetles that survive in the logs and emerge.


Right now, many of the ponderosa pine trees uprooted by the tornado are covered with the fine reddish-brown boring dust created as the beetles burrowed into the stems and branches. Once inside, the adult beetles lay eggs and once those eggs hatch the larvae feed and grow inside the wood.  They will emerge as adults sometime in July.


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