Sonoma County restricts use of Roundup, other synthetic pesticides

Sonoma County this week became the fourth local government agency in the county to restrict use of synthetic pesticides on public land.|

Sonoma County this week became the fourth local government agency in the country to restrict use of synthetic pesticides on public land, joining a wave of cities and counties across the nation that are banning a chemical deemed by some to cause cancer.

Santa Rosa, Windsor and Sonoma have previously precluded application of synthetic weedkillers on public property, with Sonoma specifically targeting glyphosate, the main ingredient in Roundup, the widely used herbicide manufactured by Monsanto.

At least 38 California cities and counties in California have now adopted bans on synthetic pesticides, along with jurisdictions in 22 other states from coast to coast, according to Baum, Hedlund, Aristei & Goldman, a Los Angeles-based law firm that has won three cases against Monsanto with $2.4 billion in damages.

The pesticide rebellion gained momentum in 2017, when glyphosate was added to California's Proposition 65 list of cancer-causing chemicals.

Megan Kaun, a Sebastopol resident who developed the county measure in collaboration with Supervisor Lynda Hopkins, began her campaign in 2015 when she found out glyphosate was being sprayed on a playground near her former home in Santa Rosa. Last August, the city prohibited use of synthetic weedkillers at dozens of parks, buildings and medians.

Windsor banned synthetic pesticides from public property last year, and the town of Sonoma barred use of glyphosate in April.

The newest regulation applies to lands maintained by county agencies, including water, parks, roads and the open space district, requiring them to eliminate use of synthetic herbicides, insecticides and fungicides to the “maximum extent practicable.”

Those lands include about 12,000 acres in 57 parks, trails and marinas managed by Sonoma County Regional Parks and 1,386 miles of rural roads maintained by the Transportation and Public Works Department.

It is not an absolute ban, allowing pesticides for use on “targeted, specific weed infestations,” and the two agencies say they cannot immediately quit using synthetic pesticides. The transportation agency is about to launch a test of an organic herbicide called Weed Zap, said by its manufacturer to be 100 percent biodegradable with a “pleasant clove scent.”

The county policy bans use of synthetic pesticides on county agency campuses, sidewalks, plazas, playing fields, playgrounds and county-maintained libraries, as well as “no synthetic spray zones” to be determined this year.

It also requires annual reports on the amount and locations where pesticides are applied by county agencies, a step that Hopkins said assures transparency.

Private land is exempt from the rules. The county is prohibited from regulating pesticide use on private property, a county staff report said.

Johannes Hoevertsz, the county Transportation and Public Works director, said his agency is the major user of herbicides, spraying mainly on roadsides where it is difficult or impossible to mow.

No chemicals are sprayed near a water source or a public area such as a park, he said.

Hopkins' west county supervisorial district, with 540 miles of roads, has been a virtual no-spray zone for years, Hoevertsz said.

“We are looking for ways to reduce costs and be safe at the same time,” he said, noting that mowing costs 10 times more than spraying.

At the county airport, spraying is needed to keep vegetation 5 feet from runways so pilots can see the lights, he said.

Weed Zap will be tested to see if it is a suitable substitute for synthetic herbicides.

Hattie Brown, natural resources manager for the county parks department, said her agency was already moving away from spraying by “ramping up mowing and grazing,” the latter by herds of cattle and sheep.

The agency is “committed to reducing human exposure to toxics,” she said.

Herbicides will continue to be needed to combat weed infestations that “pose a threat to resource value,” Brown said.

An example, she said, is Arundo donax, commonly known as “giant reed,” an invasive species along the Russian River. Volunteers are often recruited to cut down the bamboo-like stalks, followed by specialists applying a dab of herbicide to the top of what's left.

Brown is interested in the Weed Zap test, but said organic pesticides may be less toxic to the environment yet more hazardous to the worker applying it.

Environmentalists applauded the supervisors' unanimous approval of the pesticide regulation on Tuesday.

“This is very life-affirming,” said Michael Allen, a former Santa Rosa assemblyman who is Sonoma County Conservation Action's board chairman. “It's something we have to work on forever.”

Allen acknowledged that abandoning toxic herbicides comes at a cost “weighed against the public health of the county.”

Kate Thompson of Sebastopol said she has often been exposed to pesticide spray and is concerned about its impact on children. It's also harmful to insects and other invertebrates that form “the base of the food chain” and “keep down other pests.”

Board Chairman David Rabbitt noted that passing the resolution is “the easy part,” while “the heavy lift is paying for it.”

After the board's vote, Rabbitt remarked that his back yard smells like vinegar, a common alternative to herbicides that packs a punch.

“That'll make you pass out,” he said.

You can reach Staff Writer Guy Kovner at 707-521-5457 or

UPDATED: Please read and follow our commenting policy:

  • This is a family newspaper, please use a kind and respectful tone.
  • No profanity, hate speech or personal attacks. No off-topic remarks.
  • No disinformation about current events.
  • We will remove any comments — or commenters — that do not follow this commenting policy.