Worthington planning ahead for emerald ash borer
WORTHINGTON -- The city of Worthington is preparing an action plan to mitigate the cost associated with the inevitable arrival of emerald ash borer, an invasive beetle that has wiped out entire populations of ash trees.
WORTHINGTON - The city of Worthington is preparing an action plan to mitigate the cost associated with the inevitable arrival of emerald ash borer, an invasive beetle that has wiped out entire populations of ash trees.
The notorious pests have been spotted in Martin County and Minnehaha County, S.D. - both around 60 miles from Worthington. City forestry officials believe it’s only a matter of time before they touch down in Nobles County.
The beetles’ larvae feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. Despite being the size of a cooked grain of rice, the insects have killed more than 20 million ash trees in North America and threaten billions more.
As roughly one-third of the city’s boulevard trees are ash, the economic impact could be serious. Replacing around 1,450 ash trees planted in parks and boulevards would cost an estimated $870,000, said Todd Wietzema, public works director. That figure doesn’t include thousands of trees located on private properties.
There is no current cost-effective solution to dealing with the issue, as treatments cost around $100 for each tree and must be repeated every two years. Most cities simply remove “host” trees on right-of-ways and in parks to reduce the spread.
“There’s not a good cure-all, otherwise it would have been done already elsewhere,” said Scott Rosenberg, city forester.
The city plans to commit funds toward removal and replanting of trees, and wants to replace up to 50 or 75 ash trees - starting with those in bad shape - each year ahead of time.
This summer, Wietzema will ask the Worthington City Council to approve ordinances to deal with EAB. One potential ordinance would allow the city to remove ash trees from private property, similar to an ordinance passed to deal with Dutch elm disease.
Property owners are urged to look out for the bugs, which only infest ash trees, not any other species such as mountain ash trees.
The telltale sign is holes that have a flat side, like a “D.” Increased numbers of woodpeckers and damage to the tops of trees are a clear sign, as larvae generally work their way down the tree. Sprouts from the trunk can also be a sign.
Those that believe they’ve seen EAB in their ash trees can the Minnesota pest hotline at 1-888-545-6684 or the national EAB hotline at 1-866-322-4512.