The Texas Parks & Wildlife Department, or TPWD, in early October applied an aquatic herbicide recently approved for recreational use and fishing to manage the growth of hydrilla—an invasive plant species—in Lake Pflugerville.

ProcellaCOR, an aquatic herbicide, was applied near fishing piers, the swimming beach and the triathlon swimming area on Lake Pflugerville.

“It’s unsightly and if you have dead hydrilla ... it creates some kind of odor,” Pflugerville Assistant City Manager Trey Fletcher said.

The invasive species can additionally create problems for anglers catching lines on the vegetation and can cause difficulties for boating, according to Fletcher.

Pflugerville officials first identified hydrilla in Lake Pflugerville in 2006, per Fletcher, and conducted its first assessment in 2010. The invasive species came in from other waterways on the Highland Lakes chain, from which Lake Pflugerville draws its water.

In 2011, Pflugerville released 900 grass carp into the lake in an effort to manage hydrilla growth. Despite the introduction of the grass carp, the city in 2018 found that hydrilla coverage in Lake Pflugerville had grown by 8 percent.

“We’re using herbicide as a tool to help the grass carp control the hydrilla a lot faster. We don’t want to lose all the habitat in there, all the vegetation,” said John Findeisen, natural resource specialist for TPWD.

Though ProcellaCOR was only approved by the Environmental Protection Agency six months ago, TPWD has since successfully applied the herbicide across bodies of water in Texas. Canton City Lake and Lake Raven used the same treatment as Lake Pflugerville, according to Findeisen.

ProcellaCOR is the first aquatic herbicide approved by the EPA for use in bodies of water that are used for recreational and fishing activities, according to a press release by ProcellaCOR manufacturer SePRO Corporation.

Lake Pflugerville is also a public water supply for city of Pflugerville residents and any water drawn from the lake goes through a treatment process. The EPA stated ProcellaCOR required no restriction to potable water consumption following application.

State and city officials said it is likely, if not a guarantee, that Lake Pflugerville will require further applications of ProcellaCOR to treat hydrilla growth in the future. Findeisen believes TPWD teams will come back sometime in the spring to assess the effectiveness of the initial application.

Findeisen estimates the agency used approximately 80 ounces of ProcellaCOR to treat the lake, with TPWD covering the cost.

“We have to manage hydrilla forever so we’re going to use that menu of options depending on the time of year and the conditions that warrant it. I’m positive we’ll do additional herbicide treatments in the future,” Fletcher said.