The Blaine County Recreation District is beginning the battle against noxious weeds anew this spring. As directed by Idaho law, spot spraying along the Wood River Trails bike path will begin in the next few weeks, said Executive Director Wally Morgus.
The Wood River Trails system runs 32 miles from Bellevue to Ketchum and up into Sun Valley. All spraying will be done in the early morning and areas affected will be clearly marked with signs.
The chemical being used has a distinct odor that will linger for several days after being sprayed. Joggers and bikers are cautioned to keep pets out of treated areas until the odor is gone, Morgus said.
Noxious weeds are plant species that are not indigenous to a given area and are harmful to native plants and animals. Because the species are alien, oftentimes there are no natural systems to keep them in check and they can quickly suffocate native plants.
This season, the district is targeting knapweed, Dalmatian toadflax, puncturevine and koccia.
In order to mitigate the negative effects of the chemical, the district is using a multi-pronged approach to limit chemical use. Morgus estimates chemical use has already been reduced by one-third by spot spraying, replanting native vegetation and other alternative control methods.
Instead of spraying along the entire trail system, spot spraying targets only the weeds that are deemed noxious, Morgus said.
"The Recreation District has also engaged Whitehead Landscaping to run a test program, using its compost tea, to control weeds," Morgus said. The test site for Whitehead runs along the east side of the bike path from the Hailey Cemetery road south about a quarter-mile.
The compost tea begins as a vermicompost, a mix of organic materials at varying stages of decomposition and earthworm castings. Whitehead Landscaping then extracts the desired microbiological ingredients and will treat soil along the Wood River Trails. This is the second year the district has tested the compost tea, said Josh Green, spray manager for Whitehead Landscaping.
Weeds require a specific soil condition to germinate, Green said. After several years of treatment, the soil can reach a certain organic composition that leads to nitrogen propagation. The soil itself should begin to combat weeds.
"This is more of a three- to five-year deal," Green said. In effect, "we are trying to work ourselves out of the job."
For the duration of the spraying process, the district will continue to post signs at the access points of the bike path.
In addition, the district will "position a staff member in front of and behind the certified spraying technician as he moves along the bike path to alert people that the spraying is in process," Morgus said.