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Pheromones Not Recommended Treatment for Mountain Pine Beetles



For Immediate Release: March 26, 2012
Media Contact: Greg Josten, 605-394-2395


Pheromones Not Recommended Treatment for Mountain Pine Beetles


PIERRE, S.D. - As mountain pine beetles spread to private lands in the Black Hills, there has been increased interest in the use of pheromones to manage the insects.


Pheromones are chemicals released by insects, including bark beetles, to communicate with other insects of the same species. 


Chemical components of mountain pine beetle pheromones have been commercially synthesized, in the form of baits and repellents, and are available for professional use to manage the insect pest. 


The repellents are designed to mimic the pheromone released by the beetle after a tree has been mass-attacked. It sends a message to other beetles that “this tree is full, go find a different one.”


“One would think that pheromone repellents are the perfect solution to protecting valuable pine trees, but our field tests show that they don’t work on Black Hills ponderosa pine,” said Ray Sowers, State Forester with the South Dakota Department of Agriculture. “Trees that have the repellent attached to them are infested at the same rate as trees without the repellent.”


Another type of pheromone attracts beetles, and is commonly referred to as a bait. The bark beetles are intentionally drawn to baited trees, thereby concentrating the attack in fewer trees rather than having a scattered infestation.  After the beetle flight is over, the baited trees are destroyed before the next generation of beetles can emerge.


While that appears to be a simple means of managing the insect, it is not without considerable risk. If the trees to be baited are not carefully selected by foresters specifically trained in the bait application, the entire pine stand may be attacked and killed instead of just a few trees. These are called “spillover” attacks. 


“The indiscriminate use of baits is the one tactic that can make the mountain pine beetle epidemic worse. We do not recommend that private landowners use, or allow the use of baits, on their property,” Sowers said. “Private landowners should keep in mind that intentionally drawing beetles to an area may create a liability for them if spillover attacks occur on adjacent property as a result of the baiting activity.”


Baiting in other regions of the West by private landowners has resulted in the loss of thousands of pines.  Those baited trees were improperly selected, often in a line, as an attempt to create a barrier or near major concentrations of the insects. The attractive power of the baits resulted in not only killing the baited trees, but also killing many of the surrounding trees. 


“Even the use of lethal baiting where the baited tree is sprayed with a pesticide to kill the beetles as they attack can have unintended consequences,” Sowers said. “Only the sprayed tree is protected from successful attack while spillover attacks can occur in surrounding trees.”


More information about controlling mountain pine beetles can be obtained by calling the Division of Resource Conservation and Forestry at 605-394-2395 or by visiting www.Beatthebeetle.com


Agriculture is South Dakota's No. 1 industry, generating nearly $21 billion in annual economic activity and employing more than 80,000 South Dakotans.  The South Dakota Department of Agriculture's mission is to promote, protect, preserve and improve this industry for today and tomorrow.  Visit us online at http://sdda.sd.gov or follow us on Facebook and Twitter.


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*Sowers (SOW’-erz)