TAYLORSVILLE — They're the perfect predator for the notorious goathead or puncturevine weed.

Puncturevine weevils — tiny, black beetles — burrow into the spiny seed to lay their young. When the larvae hatch, they literally devour the burr from the inside out.

That's why 25,000 of the hungry insects were gently scattered along stretches of the Jordan River Friday to tackle the trail's persistent goathead troubles.

The noxious puncturevine weed has remained a top complaint among bicyclists and dog walkers for years, said Laura Hanson, executive director of the Jordan River Commission. The weed's seeds harden into thorns during late summer and are infamous for puncturing tires and paws.

"We have this beautiful, multimillion-dollar trail system, and yet sections of it are all but unusable certain times of the year because people come down only to get four flat tires, they're discouraged, and they decide to ride their bikes elsewhere," Hanson said.

About two dozen volunteers gathered in Millrace Park in Taylorsville to help release the weevils. They took handfuls of little cups, each filled with about 250 of the insects, before deploying out along nearly the entire length of the trail corridor.

Hanson said about two-thirds of the Jordan River Parkway Trail, which runs 45 miles through the Salt Lake Valley and connects 15 cities, has puncturevine problems.

"This river and the trail system can be such a great asset for our region, but it's going to take all of our efforts to really help realize its full potential," she said.

It's the fourth year the commission has released the beetles to help remove the weed from along the Jordan River — a task that will likely take at least several more years, Hanson said, since each plant can produce up to 2,000 seeds that can survive in soil for up to seven years.

The weevils, however, have been making noticeable progress, according to Hanson.

A section of the trail between 3300 South and 3900 South had been previously overrun with the weeds, but now they've almost been eliminated, she said.

"We've been slowly tackling the most problematic areas, but if we keep on it, I think we'll be able to get it under control," she said.

Hanson added that the weevils will not only help make the Jordan River more enjoyable, but they will also help improve the river's ecosystem.

That's because puncturevine — an invasive, nonnative plant — "crowds out" native grasses and other plants, which act as forage and habitat for about 200 species of birds along the river.

The weevils are also nonnative, Hanson pointed out, but they've been federally approved to come to the U.S. because they've been determined to only eat the puncturevine plant.

"They're the weed's natural predator," she said.

Adrienne Shearer-Davis, of Taylorsville, spent Friday morning with her four children in West Valley City, carefully placing the weevils on the puncturevine lining the river trails.

"I don't know that much about weevils," she laughed," But I do know that these weeds are a problem, and if there's a solution as simple as this without killing all the vegetation, I think it's great."

This year's puncturevine removal efforts were funded through a $12,400 grant from the Utah Department of Agriculture and Food.

"It's great when government or other entities can think outside the box and be proactive in innovative ways, such as using these weevils," said Salt Lake County Councilwoman Aimee Winder Newton, who also serves on the Jordan River Commission. "It's really great to take care of the environment while also taking care of a problem that's affected a lot of people."

Email: kmckellar@deseretnews.com

Twitter: KatieMcKellar1