Can The Public Trust the Pesticide Notices in Our Parks?

2016-11-02_mtd-imazapyr-blackberry-thumbnailOne of the main issues the public has with the use of pesticides in our parks is the lack of transparency. There is no way to know in advance where the San Francisco Recreation and Parks Department (SFRPD) plans to use pesticides. The only way to track pesticide use by SFRPD is to do as we do – get the monthly pesticide use reports each month and compile them. This is of course after the fact, sometimes as much as a month or two after the fact. Right now, the latest report we have is for August 2016.


In the first 8 months of 2016, the Natural Areas Program – now rebranded as the Natural Resources Department (NRD), as though they were handing out mineral rights or something – was the most frequent user of the most hazardous herbicides. They made 87% of the applications, and used 72% of the four hazardous herbicides, though they are responsible for a quarter of our San Francisco parks.  (These are all herbicides the San Francisco Department of the Environment classifies as Tier I, Most Hazardous, or Tier II, More Hazardous) The SFRPD has done an excellent job of reducing the use of toxic herbicides in other sections, but the NRD, the former NAP, has not kept up.

  • Of the 95 applications of herbicides, 83 were by the NRD.  This is important to park-goers because the NRD controls major park areas where people recreate and explore with family and pets, and this frequent use increases the probability of an encounter.
  • The NRD also applied 72% of SFRPD’s total use of the four major herbicides: Roundup (glyphosate); Garlon; Imazapyr and Milestone VM. The first two are Tier I and the second two are Tier II.
  • Though NRD has sharply reduced its use of Roundup, it used more of the other three chemicals in 8 months than it did all year in 2015.
  • In addition to the four major herbicides, SFRPD did use Avenger, an organic – though Tier II – herbicide in the Polo fields and the Golden Gate Park nursery. We are not very concerned because this is a safe organic herbicide.
  • Aside from NRD, the most frequent SFRPD user of herbicides was the nursery, which applied herbicides only seven times in eight months. The nursery is not commonly used by the public and pets .
  • This summary excludes Harding Golf Course, because it’s managed under contract by the PGA Tour and is required to maintain tournament-readiness at all times.


At the site, SFRPD is supposed to post notices three days in advance of herbicide applications. People have complained that the notices are not very visible. We are also finding they are not always accurate.

This notice on Mt Davidson clearly indicated that Imazapyr was to be used against blackberry. It gave dates and times, and said blue dye would be used to show pesticide use. Okay.


A couple of walkers saw the actual herbicide activity. Here’s the gist of their report:

Herbicides used on Mt. Davidson today, November 2, 2016.

  • Three RPD trucks, two Shelterbelt trucks.


  • Saw 3 notices – two on western slope, one on eastern. All mentioned Imazapyr (Polaris, Stalker) for use on blackberry.


  • Saw an NRD staff person as he pulled up to the top of the mountain in the truck. He said they were daubing (not spraying) cotoneaster and blackberries. The notices didn’t mention cotoneaster.


  • Saw another NRD staff person on the western side, just where the vegetation changes from grass/brush to trees. He was cutting down “a nice-looking small (but over 15 feet tall) eucalyptus tree and applying herbicides to the stump.” He said he was protecting 1000 year old biodiversity by cutting the tree to prevent it from shading the “important” plants.

    “He may have cut more trees,” the observers noted, “But we had to leave and didn’t see how many.”  The notices didn’t mention eucalyptus.

So the notices are incomplete, at best. This one didn’t mention cotoneaster, though the NRD employee said it was being targeted. What the observers actually saw was eucalyptus being cut down, also not mentioned. And unless the herbicide being put on the stump was imazapyr – unusual in this application – then the notices  also omitted the actual herbicide used – generally Roundup or Garlon.

Since the notices and the pesticide use reports are the only primary information source, if these are corrupted, then there is actually no accurate record available.

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