For The First Time, League to Save Lake Tahoe Supports Herbicide Use

The League to Save Lake Tahoe is funding the first study of aquatic herbicides at Lake Tahoe. The lagoons at the Tahoe Keys are frozen right now, but invasive weeds, which are dominant in the summer, lurk beneath the ice. 

"[It - Eurasian Watermilfoil] makes it look like a big swamp," says John Larson of the Tahoe Keys Property Owner's Association.

The weed is choking 90 percent of the lagoons. Now, another more aggressive species - Curly Leaf Pond Weed - is starting to take over, too.

“Curly Leaf Pond Weed is not widely spread around Lake Tahoe and if it does [spread], it is a downward spiral from there,” says Nick Petrell of the Tahoe Keys Property Owner's Association.

Petrell rents boats at the keys and sees them carrying the invasive species out into other parts of the lake.

“By the time our customers get from here to the channel, half the time they will suck up weeds,” says Petrell.

Just a fragment of a weed can start an infestation and stopping the spread is essential for authorities.

Larson says this dynamic threatens the very identity of the Keys as a boating community.

“At some point in time, somebody is going to say, 'well, gee should we allow boats in and out of the keys?' For 30 years, the 1,500 Keys’ homeowners have spent more than $10 million using nine methods trying to beat back the weeds. But the weeds only multiplied – 100 fold," says Larson. “It comes back bigger, badder and stronger.”

Jesse Patterson is an aquatic biologist and the Deputy Director of the League to Save Lake Tahoe. The league has pledged $100,000 to help the Keys Property owners test a new method to kill the weeds, EPA-approved aquatic herbicides.

“We think that the way that the Tahoe Keys have designed their test has enough safeguards in place that this test will not in any way put the lake at risk,” says Patterson.

The testing starts next spring and the herbicides will only be applied to a fraction of the lagoons.