It’s not easy to find information about herbicide use by land managers. We make inquiries and public records requests of all the managers of public lands in the Bay Area. Despite these persistent efforts, we have never been confident that we have the complete picture. We are therefore grateful for a recent survey conducted by the California Invasive Plant Council (Cal-IPC) of land managers—public and private—about the methods they use and for what purposes. The following charts tell us what Cal-IPC learned from their survey.
Cal-IPC sent surveys to 100 land managers who described the lands they managed as follows:
| Organization* | Response |
| Local agency | 54% |
| Federal agency | 53% |
| State agency | 48% |
| Land trust or other private landowner | 40% |
| Private consultant | 26% |
| Other (nonprofit, forestry company, utility, regional park district, conservation district) | 27% |
| *multiple employers |
How frequently are the following objectives part of land managers’ reason for managing invasive plants?
Non-herbicidal methods used by land managers to control invasive plants
|
Method |
Always |
Frequently |
Rarely |
Never |
| Pulling with hand tools |
9% |
76% |
14% |
1% |
| Digging with hand tools |
8% |
64% |
24% |
4% |
| Cutting with pruners or loppers |
7% |
59% |
27% |
7% |
| Weed whacking with string or plastic blade |
7% |
52% |
27% |
14% |
| Cutting with hand saw or chainsaw |
3% |
52% |
34% |
10% |
| Mowing with large equipment |
3% |
44% |
26% |
27% |
| Brushcutting with metal blade |
2% |
30% |
37% |
30% |
| Grazing |
0% |
29% |
23% |
47% |
How often do land managers use herbicides for invasive plant control?
What methods do land managers use to apply herbicides?
| Method |
Always |
Frequently |
Rarely |
Never |
| Foliar spray – spray to wet |
8% |
69% |
19% |
4% |
| Foliar spray – thin line |
1% |
13% |
30% |
55% |
| Foliar spray – low volume/high concentration |
1% |
22% |
35% |
42% |
| Basel bark application |
2% |
17% |
44% |
37% |
| Cut stump application |
4% |
49% |
35% |
13% |
| Drill and inject application |
1% |
11% |
30% |
58% |
| Girdling or frilling application |
1% |
5% |
43% |
51% |
| Broadcast application |
1% |
23% |
45% |
31% |
| Wick application |
2% |
6% |
44% |
48% |
| Aerial application |
0% |
4% |
13% |
83% |
What herbicides are used by land managers?
| Active Ingredient | Response Percent | |
| Glyphosate (e.g. RoundUp, Aquamaster) |
99% |
|
| Triclopyr (e.g. Garlon 3A, 4A) |
74% |
|
| Aminopyralid (e.g. Milestone, VM) |
50% |
|
| Clopyralid (e.g. Transline, Reclaim) |
45% |
|
| Imazapyr (Chopper, Stalker, Habitat, Arsenal) |
42% |
|
| Chlorsulfuron (e.g. Telar) |
31% |
|
| Fluazifop (e.g. Fusilade) |
20% |
|
| 2,4-D (e.g. Amine 4, Weedar) |
12% |
|
| Acetic acid |
6% |
|
| Clove oil (e.g. Matran |
5% |
|
| Pelargonic acid (e.g. Scythe) |
2% |
|
These charts were shown by the Executive Director of the California Invasive Council (Cal-IPC) at a meeting of the Integrated Pest Management Program in San Francisco on February 6, 2014. He explained that the survey of land managers was conducted to assist Cal-IPC in preparation for a new edition of best management practices for managing invasive plant species in wildlands. That publication will include risk assessments of the herbicides being used by land managers. Cal-IPC is collaborating with the author of the risk assessments of potential herbicide use for the Marin Municipal Water District. We look forward to the publication of this document, which is anticipated in June 2014. We hope that land managers will have confidence in the risk assessments of the herbicides they use, given the source of the information.
We make note of …..
According to this survey of land managers:
- Ninety-four percent of land managers are using herbicides to control plants they consider “invasive.” Sixty-two percent are using herbicides frequently.
- Seventy-four percent of land managers are using Garlon, which is one of the most hazardous herbicides available on the market, as rated by the Environmental Protection Agency.
- Many land managers are using Milestone and imazapyr which are known to be mobile in the soil as well as persistent in the environment according to the manufacturer’s label and the Environmental Protection Agency.
- Foliar spray is the method used most frequently by land managers to apply herbicides. This method of application has the potential to drift into non-target areas.
These practices are not adequately acknowledged in the environmental impact reports for the ecological “restoration” projects in the Bay Area. Some environmental impact reports have not acknowledged the types of herbicides being used or the methods used to apply them. None of the reports have acknowledged the quantities used by the projects nor have they acknowledged the toxicity of the herbicides. The public is therefore unaware of the extent to which herbicides are being used by these projects and the risks associated with using them.
Conservation Sense and Nonsense 
As far as I am concerned, the levels and types of use of herbicides that this report illuminates are THE issue that you folks are to be commended and supported for trying to stop happening. Your arguments about nativism vs non-nativism, invasivism vs naturalizement, species diversity vs species diversity, the value of treed ecosystems vs the uselessness of shifting sand dune ecosystems, the benefits of certain plants to certain species in a modern agricultural model and changing climate, etc., I find more to be arguments between justifications for one set of human desires over another, all attempting to use “science” to make the cases, each ab-using science to one degree or another.
But cellullar process disruption is not a value judgement, beyond valuing life itself. In my opinion, IT DOES NOT MATTER WHY these public land managers choose to use the biocides they use in the quantities and manners that they use them. They are simply WRONG, period, to use them in those quantities and manners, if they use them at all, and if they insist on doing so for any reason, they are a danger to all life on this planet and need to re-incarnate as things which cannot make such decisions ASAP.
Thank you so much for yet another brilliant post. There is no need ever for herbicide or any other poisons. We’d been told when moving in to where I live that spraying for termites absolutely had to be done, not learning until much later how easy termites are to control in the Bay Area without poisons. We don’t know what they used, but I can still smell it 36 years later. We suspect it’s the infamous now-banned Chlordane. One of our household has had two separate rare and particularly invasive cancers. We are all chronically ill.
I’ve seen California newts dying terrible deaths after crawling through roadside sprayed areas on watershed land. Again, absolutely no reason to do this. The plants they spray die naturally when the rains end, but don’t have the volatile chemicals on them. When I tried to talk with those in charge of the poisoning of our environment, I was told the poisons were safe. I sent them information proving otherwise. Their next response: “We’ll lose our jobs if this is stopped.”
There is so much talk of not enough money for basic services, but an enormous amount is spent on destroying our health and contaminating our environment, for no rational reason, Meanwhile, the deals continue, making Monsanto, Dow, etc. richer.
Fire control is often the excuse for herbiciding our parks and roadside areas, but it never makes sense. They spray right next to the bay, in endangered animal habitat, like where the Clapper Rail is trying to survive.
How many people and animals have died as a result of this poisoning our environment? How many are permanently chronically ill?
Thanks, Bev Jo. Yes, we hear about fire hazard mitigation often, so we were very surprised that few land managers consider that the reason why they are using herbicides. This survey was a reality check on many claims we hear native plant advocates make about their destructive projects.