The emerald ash borer, an invasive species from Asia, has been killing ash trees slowly but surely over the past few years. Soon, Lake County Forest Preserve District officials are hoping another insect will help fight off the pesky bugs.
LCFPD officials plan to release an experimental group of wasps in the Sedge Meadow Forest Preserve in Gurnee. The wasps lay their eggs inside the larvae or eggs of emerald ash borers, and their offspring then feed off the larvae, killing it slowly.
The wasps are not harmful to humans or trees because they specifically target emerald ash borers, according to Matthew Ueltzen, chief of LCFPD’s natural resource crew.
Wasps Kills 90% of Larvae Per Tree
Right now the wasps still are in the experimental stage and will be provided free of charge, according to Ueltzen. If the LCFPD does not receive wasps this year, they will become available again spring of 2012.
“We’re an approved site for releasing them, but there’s no guarantee we’ll get them this year,” Ueltzen said. “The breeding facilities are getting to the entire country, and we don’t know where we stand on the priority list.”
The wasps come from a Department of Agriculture research project and data suggests the wasps are capable of killing up to 90 percent of emerald ash borer larvae in a single ash tree. Michigan was the first state to release the wasps in 2008.
In much the same way, the wasps could work to kill off the emerald ash borer. Ash trees are killed slowly because emerald ash borer's larvae feed off the interior of ash trees, cutting off the flow of nutrients.
Ash Tree Death Toll in Lake County
The insect has been spotted in nine other states. In Lake County, the insect has affected 27 trees in , and 300 trees in . Ash trees make up 20 percent of the tree population in Lake County forest preserves.
“We’re seeing only minor damage in a couple of our preserves,” Ueltzen said. “But it is here, it is spreading, and we’re at the leading edge of that wave. In a couple years, we will have significant damage.”
For now, officials are dealing with the existing damages using insecticides or cutting down trees affected by the emerald ash borer, according to Michael Fenelon, LCFPD's director of planning, conservation, and development.
Reforestation Plan Needed
A more proactive approach is needed, however, according to Fenelon.
“The biggest thing we have to do is to have a reforestation plan,” Fenelon said. “We need to determine where to put new trees, what species, and whether or not we want more ash trees.”
Future ash tree losses, however, are inevitable.
“We’re going to see dramatic die-offs in the next years and increasing every year,” Fenelon said. “That’s the expectation based on previous history.”