06/03/15 Termites in mulch not a concern for Minnesotans

Termites in mulch shouldn't be a concern for Minnesota residents, says Jeff Hahn, entomologist with the University of Minnesota Extension Service

Hahn says there's been a widely circulated e-mail on the Internet recently warning people about mulch that could be infested by termites. The e-mail explains that Formosan termite-infested trees that were blown over in Louisiana due to hurricane Katrina are being mulched. Then the mulch will supposedly be shipped across the country where unknowing homeowners purchase and spread it in their garden.

The claim is that by spreading this mulch, homeowners are risking their homes to severe termite damage. Many Minnesotans have been wondering if this is true, and whether it could happen in this state.

"The short answer is that while it's not impossible, it is very unlikely that Formosan termites would be inadvertently brought into Minnesota," Hahn says.

The e-mail implies that it was written by someone from Louisiana State University (LSU), giving it an air of credibility. However, LSU is not the source of the email, Hahn says.

There was a related news release written by an entomologist from LSU last October. In the release, he warned people that they could spread Formosan termites around the state and other parts of the country by using railroad ties, reusing architectural wood, or other whole pieces of wood or lumber that were infested with Formosan termites.

So why is it unlikely for these termites to find their way to Minnesota? First, there is the issue of trees being mulched. Hahn says entomologists universally agree that it's highly unlikely that termites in wood could survive the destructive nature of the chipping process.

Once trees are mulched, this wood debris does not remain in one place long before it's removed to be burned or deposited in an approved landfill. This gives termites in adjacent areas very little opportunity to infest it.

In fact, wood debris does not even leave Louisiana, as there has been a long-standing quarantine in the state for the 12 infested parishes. This was put into place to help protect against Formosan termites being accidentally spread. No wood or cellulose materials may be moved out of these quarantine areas without Louisiana Agriculture Department approval, including all materials from Katrina cleanup efforts. If any type of wood debris is moved out of the quarantine area, it is being done illegally.

Even if despite all of these efforts, termite-infested mulch is moved north, the termites' chances of survival are quite low. The reduced moisture and greatly increased heat in a shrink-wrapped pallet of bagged mulch would be very detrimental to termite survival. Also, Formosan termites are not tolerant of cold temperatures. They do not survive prolonged exposure to temperatures in the mid 40'so F. Currently, Formosan termites are not known to infest areas further north than Memphis and Atlanta (35o N latitude).

"While the chance of encountering these termites is slim, be aware of any unusual insects that are associated with mulch," Hahn advises. Termites are white, soft-bodied insects about one-fourth of an inch long. If you believe you may have encountered termites, place your mulch in a black plastic bag, seal it tightly, and leave it out in the sun. The mulch inside the bag will heat up and eventually kill all insects in it. If you need help identifying insects, contact your local Extension office.
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