Opponents of using herbicides to kill weeds say they are "cautiously optimistic" about news from Caltrans that the state agency is considering alternatives to broadcast spraying herbicides along the roadsides of San Mateo County's state highways.

In October, responding to requests from a wide array of local groups, farmers and ranchers, and public officials who asked Caltrans to stop using herbicides along county highways, Caltrans officials promised to make some changes, starting with a pilot program on Highway 84 between Portola Road in Woodside and the coast.

The pilot program, in which Caltrans said it would continue spraying herbicides on the westbound side of Hwy. 84 while using mechanical mowing and other manual weed control, including mulching, on the eastbound side, was originally announced to start in the fall of 2015.

The program was not greeted with universal acclaim, however. Some residents said that alternatives to broadcast spraying herbicides are well-known and a pilot program was unnecessary.

Caltrans has delayed starting the pilot program, and on Jan. 19 sent out an announcement saying: "We are further assessing our operations to figure out what changes we can implement. As of this time, there is no set date for further spraying. In the event spraying is to occur on State Route 84, we will provide timely advance notice to all interested parties."

After the statement was released, Caltrans spokeswoman Gidget Navarro said that Caltrans is considering alternatives to herbicides throughout San Mateo County. However, she said, the consideration was not due to public pressure but that "this is always part of our Integrated Pest Management Policy ... to look at all alternatives for weed abatement."

She also said at that time that Caltrans would continue with the pilot program, which includes spraying.

On Feb. 3, in response to questions about when it might resume spraying, Caltrans issued another statement saying the department "is examining several options that might allow a reduction in the amount of spraying within the pilot program."

At the same time, Ms. Navarro said, "Caltrans will probably do some spot spraying soon but no broadcast spraying." Ms. Navarro said that spot spraying is done on isolated small areas or at the base of plants that have been removed to prevent re-sprouting. Spot spraying is done from sprayers mounted on back packs or all-terrain vehicles, she said.

Broadcast spraying, which local residents say is the most objectionable method of using herbicides, consists of "applying a spray solution uniformly over an entire treated area," she said, and is used to treat large land areas, roadsides and agricultural fields.

Among those who had been pressuring Caltrans to stop broadcast spraying herbicides in San Mateo County is state Sen. Jerry Hill, D-San Mateo. The pilot program for Highway 84 was announced at a Sept. 14 meeting organized by Sen. Hill that included Caltrans District 4 Director Bijan Sartipi, deputy district director Nader Eshghipour, and public information branch chief Bob Haus; San Mateo County Supervisor Don Horsley, staff members representing state assembly members Kevin Mullen and Rich Gordon; Silicon Valley Bicycle Coalition board member Peter Ingram and Lennie Roberts, a Ladera resident and legislative advocate for the Committee for Green Foothills.

Since then, Sen. Hill said he and his staff have learned that there are areas in Marin County and elsewhere where Caltrans doesn't spray herbicides. "They have made the decision elsewhere to discontinue spraying," he said. "We raised the idea: Why is this different?"

"They can't really justify using the spraying when there are alternatives available," he said. "I think they are listening. I hope this is an indication of that."

Sen. Hill said his goal is "that we can put an end to (herbicide spraying), if possible."

Caltrans, he said, wants "to be sensitive to the community that they find themselves in."

"This is a big state," and each county is different, he said. Caltrans needs "to be sensitive to those differences," he said. "I think in our area we have a very strong environmental consciousness."

Patty Mayall, a La Honda resident who lives near Highway 84 and is director of Protect Our Watershed San Mateo County, said she is "encouraged" that Caltrans is considering alternatives to broadcast spraying herbicides.

"I'm grateful for any consideration of changing this practice, and leaving herbicide spraying in the past," Ms. Mayall said. She said she hopes Caltrans will work with the local community and seek its help "with the mowing, with removing invasive plant species and possibly planting native plants that require less mowing."

However, she said, "we still don't know when, where or what" herbicides Caltrans is using for weed control. "I think it is an issue of public health and safety and protecting our environment," she said.

On its website, Protect Our Watershed calls itself "a grass-roots, watch-dog community organization promoting awareness of and alternatives to pesticides and other risks to our watershed, public health and environment." It was formed in 2015, but Ms. Mayall has been working to end pesticide spraying since 2006.

Ms. Mayall said she has urged local residents to keep an eye out for, and report, any public agencies doing herbicide spraying. Herbicides are commonly applied at this time of the year, she said. Ms. Mayall said signs a roadside has been sprayed with herbicides are usually seen 3-5 days after spraying, and include "noticeably, completely brown, dead vegetation in a three-foot, or larger, path along the roadside."

Go to ProtectOurWatershed.org to make reports on the contact form.

In 2012 San Mateo County banned broadcast herbicide spraying by the county everywhere except at its two airports. The ban only applies to county agencies, however, and not to cities and towns within the county or to Caltrans.