Native Plants and Pesticides: Glyphosate at Lake Merced

It was inevitable: a walk into a Native Plant area (aka Natural Areas Program areas) yielded yet another new pesticide notice. Last time, Imazapyr at Stern Grove. This time, Aquamaster at Lake Merced, targeting ludwigia (water-primrose).

Aquamaster is a pesticide based on glyphosate, and has been advertised as one of the safest toxins out there. New research suggests this safety may have been overstated; we posted recently about glyphosate and birth defects. Since these defects also appear in the chicken embryos that were used in the experiments, we’re not confident that herbicides will boost the breeding success of Lake Merced’s water-birds. [Edited to add: And the red-legged frog — see the comment below from MillionTrees.] (Then again, it is next to a golf course, where more herbicides are used.)

There’s a spiffy new format for pesticide reports, shown above. And it’s true Integrated Pest Management is an improvement – if it’s actually implemented.

When someone sent us a copy of the pesticide use reports for San Francisco’s Natural Areas Program, we learned:

  • They were incomplete (some areas where we’d seen notices weren’t reported);
  • Some of the pesticides which were reported had been used in unpermitted ways (e.g. sprayed instead of applied directly);
  • Pesticides had been used without prior approval (e.g. Imazapyr at Stern Grove).

With the record-keeping being a bit iffy, we will take it on faith that pesticide use has been drastically reduced, but the actual numbers may be speculative.

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2 Responses to Native Plants and Pesticides: Glyphosate at Lake Merced

  1. milliontrees says:

    This pesticide notice raises many interesting questions. Lake Merced is one of the few places in San Francisco that has been officially designated as red-legged frog habitat (see Therefore, use of certain pesticides (including glyphosate) is banned in that area unless the application meets certain criteria for exceptions to that ban.

    One of the exceptions is that if the targeted plant has been officially designated as “invasive” by the California Invasive Plant Council, the pesticide may be used with certain restrictions. About 200 plants have been officially designated as “invasive” by the CIPC (which is dominated by native plant advocates;

    The target of the pesticide application on this notice is Ludwigia. It is one of the plants on the official list of “invasives.” BUT, there are restrictions on the exemption ( One of those restrictions applies to this pesticide application notice: “Application is at least 15 feet from waterbodies described above.” This pesticide application notice says the pesticide will be applied “near shoreline.” Is the “shoreline” at least 15 feet away from the water? Seems like a potential violation of the lawsuit that led to these complex rules.

    This illustrates several issues with pesticide use in the so-called “natural areas.” The US Fish & Game rules regarding pesticide use in proximity of red-legged frogs resulted from a lawsuit by the Center for Biological Diversity. The reason for the suit is that the banned pesticides are known to be harmful to amphibians. Since the red-legged frog is an officially designated endangered species, it benefits from legal protections. There are many other amphibians that are also harmed by these pesticides, but since they aren’t legally designated as endangered, they aren’t protected. But even if the amphibian has the good fortune of being legally protected, it doesn’t benefit from that protection if it has the misfortune of living in proximity to one of hundreds of non-native plants which native plant advocates have successfully designated as “invasive.”

    In other words, the eradication of non-native plants is considered a higher priority to the environmental community than the lives of animals, even native animals considered rare and endangered. Does this make sense to you? It doesn’t to me.

  2. Pingback: Twin Peaks: Fall Weather, Roundup and Garlon | Save Mount Sutro Forest

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