Microbe to control invasive mussels in open water approved by U.S. EPA


Federal agencies are exploring how a new product might be used to control mussels in open water. Photo: GLERL.

By Howard Meyerson

GRAND RAPIDS MI, –  Federal scientists working to protect Great Lakes waters and fisheries are enthused about a new commercial product called Zequanox, which kills zebra mussels and quagga mussels without harming other species. But additional research is needed before it is used widely, they say. It could have a big impact on Great Lakes ecosystems.

“Zequanox does show great promise, but our level of understanding about its use in the Great Lakes is pretty low,” said Marc Gaden, spokesman for the Great Lakes Fishery Commission, one of four federal agencies, including the U.S. Geological Survey, Great Lakes Commission and National Oceanic and Atmospheric Administration, that recently formed a collaborative to study the issues involved with broad-scale use of the molluscicide.

“We are looking to see if a comprehensive program is desirable,” Gaden said. ”It’s important to consider the impact. What would happen if you suddenly had billions of dead (decaying) zebra mussels out there. Would you end up with even more algae in the water? We have enough trouble now with anoxic (depleted oxygen) zones.

“The Great Lakes system changed pretty dramatically with zebra mussels, and we all agree that the lakes would be better off if they and quagga mussels never came. But they are well established and are now part of the food chain.”

Dreissena_polymorpha3 usgs

Zebra mussels like this one shown and Quagga mussels which inhabit deeper waters are both potential targets for Zequanox. Photo: USGS.

Commercial product

Zequanox is produced by Marrone Bio Innovations (MBI), a California-based company that in July opened a manufacturing facility in Bangor, Michigan. Zequanox was approved for open water use in July by the U.S. Environmental Protection Agency.  Previously it was approved only for closed system use by energy producers, manufacturing companies and golf courses.

MBI claims Zequanox is safe to use, does not harm native mussels or other non-target species. No waiting is necessary before entering the water or resuming recreational use after treatment. The product is a powder that is mixed with water and injected into mussel-infested areas. The active ingredients are dead cells from common soil bacterium called Pseudomonas fluorescens. The mussels take it in as food and the microbe destroys it digestive system.

The effect was discovered in the 1990’s by scientists from the New York State Museum Field Research Laboratory.

“It can be applied to any open water pond or lake as long as it (Zequanox) is registered with that state,” said Mike Toth, the Zequanox sales manager with MBI. “The states that have approved its registration are mostly those that have a prevalence of zebra or quagga mussels – Michigan, Ohio, Wisconsin, Missouri and Minnesota.”

Permit may be needed

Sarah LeSage, the aquatic invasive species program coordinator with the Michigan Department of Environmental Quality, said individuals who want to use Zequanox should contact the MDEQ permitting office to determine whether a permit will be needed for its application.

“It was a big step to get U.S. EPA approval,” LeSage said. “But it is still very much in the testing phase. In Michigan we haven’t had applications (filed) for its use. If someone wants to use it, we recommend contacting the department so we can evaluate the use.”

MBI celebrated its first commercial open-water Zequanox application in September on Christmas Lake near Minneapolis after the Minnesota Department of Natural Resources requested treatment on a lake where zebra mussels were found. It was applied to a 50- by 60-foot containment area with an average depth of 2.5 feet, Toth said. There were approximately 5,000 live mussels there before treatment. Eleven days later, all were dead.

Toth said Zequanox is best for mussel control rather than eradication. It will kill adults as well as the larva, called veligers, but it biodegrades and disappears in two weeks’ time.

Federal scientists examining how Zequanox might use it to control mussel populations in the Great Lakes, say numerous questions remain about the impact of its use on aquatic environments as well as the logistics of applications in conditions where currents, wave action and water temperatures can influence its effectiveness.

“Everyone has been looking for a tool to control invasive mussels and Zequanox is one tool that gives us hope,” said Mark Gaikowski, the director for the Upper Midwest Environmental Sciences Center of the USGS, in La Crosse Wisc. “But one thing we don’t have well-established is: what are the outcomes that management agencies want if they go out and do a control application. What is the outcome from all of those decaying mussels?  What happens as a result of treatment?”


© 2014 Howard Meyerson

This story appears in Michigan Outdoor News.





About Howard Meyerson

After more than 30 years in the outdoor writing business, you would think I'd know better.
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1 Response to Microbe to control invasive mussels in open water approved by U.S. EPA

  1. mfs686 says:

    Cautiously optimistic.


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