Editorial - Don't let ash borer invade Douglas County

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The dreaded emerald ash borer (EAB) is invading more Minnesota trees. Although the newest infestations were found in three Twin Cities locations, residents in Douglas County should be aware of the threat and do all they can to keep the destructive pests out of this area.

The Alexandria area has one of the highest percentages of ash trees in the state – about 60 percent of its trees are ash trees.

The EAB is one of America’s most destructive tree pests, having killed tens of millions of ash trees in 18 states, according to the Minnesota Department of Agriculture (MDA). Its larvae kill ash trees by tunneling into the wood and feeding on the tree’s nutrients. Infestation signs include one-eighth inch, D-shaped exit holes in ash tree bark and winding tunnels under the bark.

The MDA reported the latest infestations Friday. The sites were discovered due to the presence of ash trees with woodpecker feeding, which is a good external symptom of insect activity. The trees were confirmed as EAB-infested by removing sections of bark to reveal the insects distinctive “S” shaped tunneling on the surface of the wood.

MDA officials say finding such infested trees in the winter is far easier when the branches and trunk are exposed, compared to during the summer when leaves can disguise the symptoms.

“The discovery of these new sites is disappointing, but it is noteworthy that all three sites remain contained within the existing metro quarantine of Ramsey and Hennepin counties,” said MDA entomologist, Mark Abrahamson. “It is also encouraging that these cities have staff with sufficient expertise to identify infestations before tree decline is evident. Based on our experience with other sites, these trees have probably been infested for three or four years.”

Abrahamson added that both Minneapolis and St. Paul are aggressively working to limit damage from EAB and discovering new infestations is a key component of that effort.

The biggest risk of spreading EAB comes from people unknowingly moving firewood or other ash products harboring larvae, according to the MDA. It offers these three easy steps Minnesotans can take to keep EAB from spreading:

1. Don’t transport firewood. Buy and burn local firewood to prevent movement of EAB.

2. If you live in a quarantined county, be aware of the restrictions on movement of products such as ash trees, wood chips, and firewood. Details can be found online at http://www.mda.state.mn.us/eab

3. Watch your ash trees for infestation. If you think your ash tree is infested, contact MDA at arrest.the.pest@state.mn.us or 1-888-545-6684 (voicemail) to report concerns.

The adult EAB is a small beetle, one-third to one-half inch long, with a shimmering green body that lives outside the trees. The larva is a worm look-alike with a yellowish white coloring and lives underneath the tree bark.

Although EAB has not been discovered in the Douglas County area, it’s a threat that we can’t take lightly. Be on the lookout, follow the advice of the agriculture experts and let’s all work together to keep this invader out of our ash trees.

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