Pesticides on Blackberry in Fruiting Season

Recently, one of our neighbors was walking on Mt Davidson. It’s the time of the year when the blackberry bushes bear fruit, to the delight of children and the public in general (and not a few animals and birds). She was unpleasantly surprised to find that the bushes were to be sprayed with herbicide.

“It’s the fruiting season!” she noted, wondering if this was legal.

Unfortunately, it is.  In 2016, SF Environment imposed restrictions on spraying blackberry bushes during the fruiting season. But the way the restrictions are written, they apply only to Tier I (“Most Hazardous”) pesticides and not to the Tier II (“More hazardous”) pesticides that the Natural Resources Division (NRD – formerly Natural Areas Program) also uses quite frequently. The NRD commonly uses “the fearsome four” pesticides: Garlon, Roundup, Milestone VM and Polaris (also called Habitat). All of them are toxic in some degree.

The herbicides used in this case are Milestone VM (aminopyralid) and Polaris (Imazapyr). Both are toxic and are classified as “More Hazardous” (Tier II). Imazapyr can damage eyes, and its breakdown product is a neurotoxin, which means it causes nerve damage. Aminopyralid is a newer chemical, but is known to be astonishingly persistent. It’s banned in some places because of that.



In 2016, the SF Department of the Environment engaged in a lengthy process of trying to improve its restrictions on  some of the most problematic use of pesticides in our parks.

(You can read the entire compliance guidelines here as a PDF. It’s from the SF Environment website. sfe_th_ipm_compliance_checklist – Copy )

Among them, they developed these restrictions:

 Pesticide use

✓ A written recommendation from a licensed Agricultural Pest Control Advisor (PCA) is required for any pesticide use. Departments that do not have PCAs on staff should contact the SF Environment IPM Manager.

✓ Only pesticides on the current SF Reduced Risk Pesticide List may be used. Usage must fall within the “limitations” listed for each product, along with label requirements.

✓ ‘Most hazardous’ (Tier I) herbicides have special limitations:

  • Use is prohibited for purely cosmetic purposes.
  • Use is prohibited within 15 feet of designated paths. If a park map exists, designated paths are those found on the maps. Otherwise, designated paths are those actively maintained by staff.
  • Use is prohibited within 15 feet of schools, preschools, playgrounds, or other areas frequented by children.
  • Use on blackberry bushes is prohibited when fruit are present 
  • If within the City limits, use requires onsite supervision by a licensed person (PCA, QAL/QAC) o No broadcast spraying with a boom is permitted except for golf courses (targeted spraying only)
  • Certain pesticide use is restricted in designated Red-Legged Frog habitat, which includes Golden Gate Park, Lake Merced, and several other areas in San Mateo and Alameda County.


Posting for pesticide use must be done 3 days before treatment, and remain up for 4 days after treatment, except for least-hazardous (Tier III) products, which require posting only on the day of treatment.

✓ Postings must clearly identify the area to be treated. Signs should be placed at locations most likely to be seen by members of the public using the treated area.

✓ Posting is not required for median strips or rights-of-way when these areas are not intended for public use.

✓ Posting is not required for areas inaccessible to the public. [See our recent article on this: San Francisco Pesticides and Inaccessible Areas]

✓ ‘Most hazardous’ (Tier I) herbicides have special notification requirements:

  • Blue dye must be used, and this must be noted on the posting sign. Blue dye is not required in areas where 1) posting is not required, and 2) staining may occur, such as ornamental stone median strips.
  • When treatment sites that cannot be readily identified by the posting sign alone, a map showing the general location of expected treatment area(s) must be attached to the posting sign.


Though the added restrictions in 2016 were a step forward, much more is needed. NRD seems willing to go by the letter of the rules, not the spirit of it. Blackberry should not be treated with persistent herbicides at all, especially not in the fruiting season. It’s going to affect children, wildlife, and anyone who loves picking the berries in season… most parkgoers.

San Francisco Forest Alliance stands for Pesticide-Free Parks – including natural areas.

SF’s Natural Areas Program Uses Even More Pesticides

The 2012 final data are in, and it’s official: In 2012, the Natural Areas Program (NAP) used more pesticides than in any year from 2008 (the first year for which we have data provided by the City). This is true by any measure, as the graphs below indicate. [Note: Graph edited to indicate units]

[Edited to Add: NAP also used more Tier I pesticide – the most toxic – than the rest of SF RPD areas together. HERE]

pesticide use number n vol 2008 to 2012

Depending on the measure you choose, usage has increased anywhere from 12% to 40% from 2011. It’s between 3 and 4 times the usage in 2008.


What pesticides have they been using?

The same as before: Tier II and Tier I pesticides, defined as more hazardous and most hazardous. (For a detailed discussion of these chemicals, click HERE:  Natural Areas Program’s Pesticides: Toxic and Toxic-er.

  • Aquamaster/ Roundup (Glyphosate). (Tier II)  This is one of the world’s most widely used herbicides, but in vitro research has linked these chemicals to changes to human cells, some of which are of the kind that could cause birth-defects. The EPA is studying whether it is an endocrine disruptor. The fact that it’s widely used gives us little comfort; a different widely used herbicide has just been declared unacceptably toxic to bees.
  • Garlon (Triclopyr). (Tier I) To NAP’s credit, they have reduced the use of this extremely toxic herbicide since the peak in 2010. It’s a Tier I pesticide, and associated with numerous diseases in humans, and potential kidney impacts on dogs.
  • Polaris (Imazapyr). This Tier II herbicide is a problem because it spreads (it doesn’t stay where it’s applied) and it persists (it doesn’t break down easily). It’s a relatively new herbicide, and we don’t know quite what it does – though its breakdown product  is neuro-toxic. It’s banned in Europe, and neighbors are fighting against its use in privately owned forests in Northern California.
  • Milestone (Amino-pyralid). This Tier I toxic chemical sticks around even more persistently than imazapyr. It was banned for a time in the UK because if animals eat and excrete it, the excreta are still poisonous – as is the manure made from it. It’s banned in New York state because they aren’t sure it won’t poison the water. NAP’s used it in Lake Merced, Pine Lake, Glen Canyon, and Mount Davidson, all of which are areas where water contamination is possible. [Edited to Add: In 2013, Milestone was reclassified as a Tier II chemical.]


Of course these chemicals are not good for people, and one would think that in a city that is so conscious of organic and green produce and products, wild lands would be one area that we’d try to keep organic. Not so. We even found evidence of blackberry bushes being sprayed – during the fruiting season when children and adults, birds and animals feast on the bonanza of berries.

Recent research indicates that both triclopyr and imazapyr are potentially toxic to butterflies – but NAP continues to use both Garlon and Polaris on Twin Peaks, where NAP are also struggling to re-introduce the endangered Mission Blue butterfly. Glyphosate is known to be dangerous to amphibians; but NAP uses Aquamaster around Lake Merced, Pine Lake, and in Glen Canyon – all near water-courses.

Finally, we have another problem with this use: it may be glorifying chemical solutions. A few months ago, a “volunteer” in Glen Canyon was found applying an unapproved pesticide to an area near a trail, without posting any notices or keeping any record of amounts or conditions. He believed he was doing a good thing for the environment. We have heard since of many other instances of random herbicide application in Natural Areas.


Furthermore, the list of plants on which it’s used also keeps expanding. It’s currently around 30, up from under 2 dozen a year ago. Some of the plants being sprayed aren’t on the list of the California Invasive Plants Council or USDA noxious plants lists.

We ask SF Recreation and Parks Dept  to stop using Tier I and Tier II pesticides in the Natural Areas. An escalating use of herbicides is bad for the environment and the people, pets and wildlife using these parks;  sends a damaging message about priorities; and indicates a lack of success.

The Natural Areas Program and Pesticides: Volumes and Numbers

We talked about pesticide use in the Natural Areas a number of times, and particular of the increasing volumes of the “Fearsome Four” pesticides they use most:

  • Glyphosate (Roundup or Aquamaster);
  • Triclopyr (Garlon or Garlon 4 Ultra);
  • Imazapyr (Polaris or Habitat); and
  • Amino-pyralid (Milestone).

[Read more about the effects of these herbicides HERE: SaveSutro’s article Toxic and Toxic-er.]

We got San Francisco’s Natural Areas Program pesticide use records under the Sunshine Act, and used them to create a graph of the number of applications by year. We’ve shown this graph at some of our presentations.

Recently someone spoke to us about the graph. “I asked NAP about it, and they said that possibly the number of applications has gone up, but the amount of pesticide use has gone down because they use less in each application.”

Possibly.  And possibly not.


What we found when we looked was that volumes have increased even more. (This is based again on the data provided us under the Sunshine Act.)

  • Between 2010 and 2011 the number of applications went up 21%. The volume of pesticide (in fluid ounces) used went up by 25%.
  • Between 2009 and 2010, the number of applications went up 184%. The volume of pesticide used went up by 365%.

So here’s that graph:

(Milestone doesn’t show up here because until now, the volume of applications has been small. Possibly, given its persistence, we should count it cumulatively?)

[Click HERE for more about ” Milestone” – aminopyralid.]

Edited to Add: For those interested in details of NAP’s pesticide use, calculated four different ways (number of applications; volume; active ingredient; and “acid equivalent”) here’s an article with details:

Click here for SaveSutro’s article: Measuring Pesticide Use by the Natural Areas Program

This graph that summarizes it by comparing pesticide use on various measures to 2008 levels. Pesticide use went down in 2009, then increased sharply in 2010 by all measures. In 2011, it rose in volume terms and number of applications, and declined very slightly when measured by active ingredient or acid equivalent.


[Edited to replace with the more precise and detailed calculation, above.]

Edited to Add (for those with a technical bent): SF RPD used various formulations of glyphosate over the years. Technically, to compare them you need to calculate “Acid Equivalents” of the various formulations. We did this exercise,  converted them to Aquamaster equivalents, and adjusted the numbers. It made no significant difference. Between 2010 and 2011 the number of applications went up 21%. The adjusted volume of pesticide used went up 52%. Between 2009 and 2010, the number of applications went up 184%. The adjusted volume of pesticide used went up 264%.

Natural Areas Pesticides: The Fearsome Four

Three of the Four on Mt Davidson

The Natural Areas Program (NAP) uses four herbicides classified as “Most Hazardous” (Tier I) or “More Hazardous” (Tier II) by San Francisco’s Department of the Environment (DoE):

  • Garlon 4 Ultra (triclopyr)
  • Roundup or Aquamaster (glyphosate)
  • Polaris or Habitat (imazapyr)
  • Milestone (aminopyralid)

All these chemicals have serious problems: they’re associated with birth-defects and pregnancy failures; they’re endocrine disruptors; they poison animals, especially amphibians but also reduce bird-nesting success; and/or they’re persistent – they stick around.

For details of the risks associated with each one, read the article Natural Areas Program’s Pesticides: Toxic and Toxic-er.

We often get questions about this, especially from people who have heard about NAP from its supporters.

Source: (derived from from SF City records)

Q:  They hardly ever use pesticides, right? Just once every few years?

A:  NAP applied pesticides 86 times in 2011, up from 71 the year before. (We’re relying on City records here. There may be gaps.)

Q: But maybe they used less in each application?

A: The amounts used went up in proportion.

Q: Don’t they use very small amounts? Doesn’t the dose makes the poison?

A: In 2010, NAP used more Tier I herbicides than any comparable park department. (We don’t have compiled data for 2011 for other parks departments.)  Anyway, “the dose makes the poison” isn’t always true. Here’s what the American Chemical Society said in its Public Policy Statement, Testing for Endocrine Disruption:

Endocrine disruption is the alteration of the endocrine system that causes adverse health effects in an intact organism, or its progeny, or (sub)populations. Endocrine hormones naturally act at ultra-low concentrations and certain chemicals are suspected of altering endocrine function at similarly low concentrations, which sometime occur in the environment. A large and growing body of environmental health literature shows that endocrine disrupting substances have complicated dose-response curves that do not fit the central tenet of regulatory toxicology, namely, that the ‘dose makes the poison.’

Q: But aren’t they herbicides… don’t they act only on plants?

A:  They act differently on plants and on animals, but they still can – and do – impact animals (and people).  They may use different bio-chemical pathways in animals and in plants, and thus have different effects. None of these effects is good. The city of San Francisco subscribes to the “Precautionary Principle” – if you don’t know the effects, don’t use it. The natural areas are where children explore, people walk, and pets are exercised. This is not a risk they should take.

Mount Davidson’s Garlon Pesticide – Again

The other day, we walked on Mount Davidson. The view from the top was lovely, and in the middle of it was a pesticide sign.

It was difficult to read because the moisture had condensed under the plastic. But we pressed it down, and were able to discern that it warned they were using Garlon 4 Ultra (a Tier I pesticide, Most Hazardous) against oxalis. (That’s the little yellow flower also called Bermuda Buttercup, or referred to as clover. Kids like to nibble on it because it’s sour.)

Oxalis grows from little underground tubers, called bulbils. Garlon isn’t very effective against oxalis because it kills the plant on top, but not the bulbils, which then can resprout.  Oxalis doesn’t set seed in San Francisco, so there’s no point killing the top of the plant before it flowers, either. It just deprives bees and butterflies of their nectar.

From the website, (which based it on a detailed study by the Marin Municipal Water Department)

These are the main issues with Garlon, in brief:

  • Garlon “causes severe birth defects in rats at relatively low levels of exposure.” Baby rats were born with brains outside their skulls, or no eyelids. Exposed adult females rats also had more failed pregnancies.
  •   Rat and dog studies showed damage to the kidneys, the liver, and the blood.
  •   About 1-2% of Garlon falling on human skin is absorbed within a day. For rodents, its absorbed twelve times as fast. It’s unclear what happens to predators such as hawks that eat the affected rodents.
  • Dogs  may be particularly vulnerable; their kidneys may not be able to handle Garlon as well as rats or humans.  Dow Chemical objected when the Environmental Protection agency noted decreased red-dye excretion as an adverse effect, so now it’s just listed as an “effect.”
  •  It very probably alters soil biology. “Garlon 4 can inhibit growth in the mycorrhizal fungi…” ( soil funguses that help plant nutrition.)
  •  It’s particularly dangerous to aquatic creatures: fish (particularly salmon); invertebrates; and aquatic plants.
  •  Garlon can persist in dead vegetation for up to two years.

The DEIR has said that the SF NAP’s phasing out Garlon.

If they are, it’s not apparent on Mount Davidson.  And we also saw another sign, this time warning about the use of Polaris (imazapyr) on cotoneaster.

West Portal Monthly: Clearcut Case of Overkill at Mt Davidson Park

The West Portal Monthly today published an article by Jacquie Proctor explaining the problem of the NAP specifically at Mt Davidson and generally throughout the city.  The plan seeks to destroy at least 1600 trees on Mt Davidson alone. Read on: