New Quagga Mussel Treatment Underway In Southern Idaho

Idaho officials have prepared a new treatment to fight quagga mussels in the Snake River near Twin Falls. The Idaho State Department of Agriculture says the multi-phase treatment will use two EPA-approved copper products, Natrix and Earthtec QZ.

What Are Natrix and Earthtec?

Natrix, has been used in the Snake River quagga mussel treatments in 2023, 2024, and 2025, which significantly reduced the quagga mussel population.
Earthtec QZ, is another copper type product that has a different formulation to address any remaining potential safe harbors in the infested area that may have quagga mussels.
Natrix and Earthtec QZ are copper-based products that are labeled and approved by EPA for this type of aquatic application. The products have been used in other states for mussel, fish, algae, and plant control.
The application rate of both products will kill mussels but is also below the drinking water standard for humans.
The product dissipates downstream and is expected to be gone within three days after the final application.
River copper levels are expected to return to normal within 25 miles, near the Highway 46 Bridge.
ISDA and the Idaho Department of Environmental Quality will routinely monitor the river to evaluate treatment effectiveness and copper dissipation. ISDA has mitigation efforts ready to deploy if additional copper is detected downstream.

Treatments started August 27th and will continue through September 13th. Officials say sampling has shown a 77% reduction in quagga mussel detections following previous treatments. The new application will target mussels hiding in small cracks and rocky areas that can serve as safe harbors.

Temporary closures are planned at the Twin Falls and Shoshone Falls boat launches during treatment. The Department said these closures are intended to allow for ISDA crews to safely and efficiently implement the treatment. ISDA said anticipated closure dates are subject to change:

Twin Falls Boat Launch: August 27 – September 5.
Shoshone Falls Boat Launch: September 6 – September 13.

ISDA recommends humans, pets, and livestock steer clear of the treatment area until mid-September.

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