Pseudomonas flourescens CL145A (Zequanox®) for Zebra Mussel Control: A Synopsis of Peer-reviewed References

Beginning in the early 1990s, researchers at the New York State Museum began investigating bacteria and their natural metabolic products as selective agents for the biological control of zebra and quagga mussels (Dreissena polymorpha and D. rostriformis bugensis, respectively). This research team discovered that one specific strain (CL145A) of the soil bacterium Pseudomonas flourescens can cause mortality in dreissenid mussels. When ingested via a mussel’s filter feeding, a metabolite associated with the bacterium’s cell wall destroys the mussel’s digestive system and leads to death. Exposure to either live or dead P. flourescens CL145A cells results in mussel mortality. Recently, dead P. flourescens cells have been formulated under the trade name Zequanox®, which has been commercially available since 2012 when the U.S. Environmental Protection Agency (EPA) approved its use for mussel control in enclosed systems (e.g., infrastructures for energy producers and manufacturing companies). The EPA approved Zequanox for open water use to combat invasive mussels in lakes, rivers, and other waterbodies in 2014. To better understand the possible benefits and effects of this product, this report summarizes the available peer-reviewed, scientific literature on P. flourescens CL145A and its effects on nontarget organisms.