Emerald ash borer discovered in Waukesha's Frame Park

Published on: 9/10/2013

Peter Traczek knew it was only a matter of time before the emerald ash borer, (EAB), was detected in Waukesha.

That time came last week when a horticulturalist discovered EAB Aug. 27 on a tree inside Frame Park.

"We anticipated it and it has been here for several years just based on the findings in the area," said Traczek, Waukesha's Parks and Forestry operations manager.

But Traczek said when the individual discovered D-shaped exit holes in a declining ash tree it showed that this is just the beginning in Waukesha. Forestry staff came out and cut the tree down and discovered the larvae of the beetle underneath the bark.

Pictures were taken and sent to the Department of Natural Resources who confirmed what was already suspected. He said the invasive, metallic green beetle grew inside that tree "for several years." It builds up and kills the trees within three to five years.

Traczek said most recently the tree pest was found in June in Mukwonago and there have been others recently spotted in Oconomowoc and New Berlin in Waukesha County. In Milwaukee County, the EAB was also just confirmed a couple weeks ago in West Allis.

"We knew it was pretty much surrounding us," Traczek said. "It's one of those pests we've been battling for a long time."

The insect kills ash trees by feeding in tunnels below a tree's bark. Traczek said these "galleries" of insects disrupt water and nutrient transport.

The emerald ash borer first surfaced in 2002 in Michigan, Traczek said and has worked its way through 20 states. In Wisconsin, it has been found in 16 counties after first surfacing in 2008 in Ozaukee and Washington counties.

Preventative measures are being taken, but Traczek was blunt on the long-term prognosis of the more than 5,000 ash trees in the City of Waukesha and in nearby cities.

"The bug is going to kill a majority of or all of the ash in most communities," Traczek said. "It's unrealistic to think that we can save (trees) but it's about managing it and prolonging the inevitable.

"So over the next 10 to 15 years what we're trying to do is manage our timeline based on mortality curves that have been determined by scientific studies."

In the city's first step against the outbreak, ash trees have not been planted on city terraces since 2006. Four years later, the city secured funding to provide pesticide preventative treatment for bigger and more mature trees.

"We're trying to remain a step ahead by using a multi-tiered approach, treating the biggest and healthiest trees while removing ash that are currently on the decline," Traczek said.

The city forester said the city has been using the product TREE-äge to treat these trees.

"It offers upwards of three years of protection," Traczek said. "There's some evidence it might last a fourth year, so that's one avenue of treating it."

There are some other treatment options the city could also look into with it being studied at the university level.

Traczek said the last destructive force to wipe out a tree population around here was Dutch elm disease that affected elm trees decades ago.

However, Traczek explained the emerald ash borer will be even worse than that outbreak.

"I haven't seen anything this bad," Traczek said. "And they go after each ash tree uniformly. When they come into an area they are non-selective."

Signs of infestation include tree canopy dieback, sprouting on the trunk or base of the tree, splitting bark on the trunk or woodpecker damage on the trunk from larvae extraction. Adult beetles leave distinctive D-shaped exit holes in the outer bark and a series of s-shaped galleries or feeding chambers under the bark.

The beetles are very tiny, Traczek says, and once they emerge in the spring they go off and mate and each female will lie between 60 and 90 eggs.

Traczek advises to use firewood in the same location at which you bought it so the beetle doesn't spread from one location to the next.

"One of the biggest culprits is moving firewood," Traczek said.

Besides ash trees, the city, which maintains more than 25,000 trees, has three other main tree populations: maple, honeylocust and linden. While Traczek said 45 percent of the ash population has received treatment, not all trees will be treated and given its budget, the city won't be able to replant all lost ash trees.

Traczek said the best avenue is to contact Waukesha County UW-Extension Horticulture at (262) 548-7779 or at Helpline@uwex1@waukeshacounty.gov. Wisconsin's EAB Hotline service is also available at (800) 462-2803.

A tree care service can also come to an individual's home to assess a tree that has been hit by EAB and whether removal or treatment is the best route to take.