Can Zequanox be the Answer to Lake Minnetonka's Zebra Mussel Infestation?

Marrone Bio Innovations, a leading provider of natural pest management products for water and agriculture applications, said this week that Zequanox was highly effective at controlling invasive zebra mussels in Deep Quarry Lake located in DuPage County, Illinois.

Zequanox, the industry’s only environmentally compatible molluscicide, was applied within barrier systems in three locations throughout the lake. Results showed that treated sites experienced an average mussel mortality of 97.1 percent compared with 11.2 percent mortality in the untreated sites.

Environmental Protection Agency approval for using Zequanox in natural water systems is currently in process.

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In the study, funded in part through a grant from the Illinois Department of Natural Resources, three sets of paired treatment and control sites were set up within the lake to evaluate the effectiveness of Zequanox. Zequanox was so effective at controlling the invasive mussels that the study concluded after just one month. The study also showed that the application of Zequanox had no impact on water quality and no adult or juvenile fish mortality was observed 24 hours after product application.

“Zequanox has proven to be a powerful tool for controlling invasive mussels in 'in-pipe' applications such as cooling water systems," said MBI Director of Water Technologies Sarahann M. Rackl, Ph.D., P.E. "This study shows the product can be equally as effective in open waters. This successful study represents MBI’s next step in our commercialization efforts for Zequanox in natural water bodies, and we’re excited about expanding into this new market, where there are currently no other environmentally compatible treatment options.”

Zebra mussels were first discovered in Deep Quarry Lake in 2009 and have since developed a well-established population within the lake. Because of their ability to reproduce quickly and in large numbers, invasive mussels can rapidly take over water systems they invade, outcompeting native species for food and space.

In addition, their thin, sharp shells cause painful cuts and wounds, and when the shells of deceased mussels wash ashore, they can ruin recreational beach areas. Currently, there are no commercially viable alternatives for treating invasive mussels in open water bodies without harming other species.

“We are very pleased with the outcome of this study," said John “Ole” Oldenburg, Natural Resources director in the Forest Preserve District of DuPage County. "The mortality rates as a result of Zequanox applications were impressive and the use of anchored barriers proved to be a an excellent method to isolate and treat mussels within specific areas of the lake.” 

The study was implemented in partnership with the Illinois Department of Natural Resources, Southern Illinois University (SIU), Forest Preserve District of DuPage County, PLM Lake and Land Management (PLM) and Marrone Bio Innovations.

Additional open water testing with Zequanox was performed earlier this year by the US Geological Service in collaboration with scientists from New York State Museum at Lake Carlos, Minnesota and Lake Shawano, Wisconsin. Further testing will be conducted in early 2013. 

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