Borrego Knows Best

San Diego County Board of Supervisors agreed Borrego Knows Best when it made its final determination on Rudyville on September 12, 2018.

Check out our campaign video, Borrego Knows Best

KPBS Televised Broadcast

TCDC supporter, Michael Bovee, produced the following video describing one aspect of TCDC’s response to the threat produced by Sahara mustard. This report was broadcast on KPBS television and radio on June 18, 2014.

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Sahara Mustard
Life Cycle Slideshow

Learn how to recognize invasive Sahara Mustard from seeds and tiny sprouts to large, mature plants.

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"Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has."

— Margaret Mead


"Don't wait for the cavalry to come over the hill to save you. You are the cavalry and had better save yourselves."

— Robert Lee Paul

Glyph of Sun


Tubb Canyon Desert Conservancy

Summer 2019

TCDC Wins Bipartisan Congressional Support in fight against Sahara Mustard

Washington DC—Friday, July 26, 2019. Ten members of the United States House of Representatives signed a letter in support of the Tubb Canyon Desert Conservancy’s (TCDC’s) multi-year project to discover a biocontrol agent that will be safe and effective in stopping the spread of Sahara Mustard (Brassica tournefortii), one of the most destructive invasive weeds in the southwestern United States. This congressional letter directs the leadership of the USDA’s Agricultural Research Service (ARS) to dedicate sufficient funding and human resources to complete the biocontrol project during ARS’s upcoming 2020-2025 Action Plan.

San Diego Representative Susan Davis took the lead in circulating the letter among Democratic and Republican colleagues in the House whose districts are impacted by Sahara Mustard. Representatives signing the letter were: Susan Davis (CA-53), Paul Cook (CA-8), Ann Kirkpatrick (AZ-2), Raul Grijalva (AZ-3), Katie Porter (CA-45), Duncan Hunter (CA-50), Salud Carbajal (CA-24), Ruben Gallego (AZ-7), Greg Stanton (AZ-9), and Tom O’Halleran (AZ-1).

(The full text of the congressional letter)

“Achieving congressional support for TCDC’s project was a distant dream in 2014 when we began what we knew would be at least a 10-year effort,” said David Garmon, M.D., President of Tubb Canyon Desert Conservancy. Garmon added, “Because Sahara Mustard’s destructive impact is being felt across the entire desert Southwest, we were joined in our effort to educate politicians about this ecosystem-level menace by dozens of organizations from around the region—State and National Parks, governmental agencies, non-governmental organizations, and academic institutions. We would not have been able to attain this milestone of a congressional letter without Letters of Support from all of these organizations along with their own outreach efforts to their individual representatives.” (Letters of Support).

In 2014 Tubb Canyon Desert Conservancy published a White Paper outlining a scientific methodology for the discovery of a safe and effective biocontrol agent capable of stemming the spread of Sahara Mustard across the deserts of the American Southwest and northern Mexico. Rather than using the traditional trial-and-error method, TCDC’s approach uses the latest genomic sequencing techniques to determine precisely where in Sahara Mustard’s extensive native range it would be most effective to search for natural biocontrol agents. Potential biocontrol agents—the predators and / or pathogens against Sahara Mustard—from these precise locations would be the agents most likely to be safe and effective against the three genetically distinct populations of Sahara Mustard that were introduced into the U.S. during the 20th century.

The letter signed by House Representatives directs USDA scientists to travel to those precise locations around the Mediterranean and in the Middle East that were identified in the first two phases of the TCDC project. In those specific locations where the Sahara Mustard now in the U.S. originated, scientists will identify the “natural enemies” of the three genetically distinct populations of Sahara Mustard that have invaded the U.S. Once identified, candidate biocontrol agents will be subjected to several years of safety and efficacy testing in special USDA biocontainment laboratories in Europe. Promising candidates will eventually be brought to USDA biocontainment labs in the U.S. for further safety and efficacy testing prior to release into the environment.

“Because Sahara Mustard is spread over millions of acres across the deserts of the American Southwest, manual eradication or using herbicides could never rid us of this destructive weed, except in a few small, constantly surveilled, high-value areas. The only possible hope of addressing this ecosystem-level threat is with a biocontrol agent that can be safely released into the environment,” said Robert Staehle, Vice President, TCDC. “That is why our effort to find a biocontrol agent is critical to the ecological health of broad portions of the Southwest, particularly our vulnerable desert and coastal dune ecosystems.”

Lori Paul, TCDC Director added, “We are grateful for the generous support of so many friends and neighbors who have made this project possible. We would not be at the halfway point in this project without the original seed-funding generously provided by Audrey Steele Burnand and the support provided by the Borrego Valley Endowment Fund for recent congressional outreach efforts.”

J. David Garmon, MD
President, TCDC


Sahara Mustard

When the neighbors on Tubb Canyon Bajada came together in 2011 to do battle with Sahara Mustard (Brassica tournefortii), it was not immediately clear what would be required to protect pristine desert habitat from this aggressive foreign invader. We began by manually removing as many Sahara mustard plants from as many acres as we could, and then surveilling those acres every winter and spring. These efforts have resulted in many acres of pristine dessert habitat in southwest Borrego Valley that are now free of Sahara Mustard; however, the problem turned out to be much larger than we knew.

Large quantity of bagged Sahara Mustard

Bags of Sahara mustard from the Tubb Canyon Bajada delivered to the Sahara Mustard dumpster formerly provided at the Headquarters of the Anza-Borrego Desert State Park on March 27, 2011.

By 2013 we learned that in the century since its accidental introduction in the arid, date-growing Coachella Valley of California, Sahara Mustard had spread up the California coast, as far north as San Luis Obispo County; eastward across Arizona, and New Mexico to west Texas; and from southern Nevada and Utah southward into central Mexico. We learned that with this broad extent of dispersal, manual eradication and herbicides would never be effective in ridding the deserts of the American Southwest of this destroyer of native vegetation. We learned that Sahara mustard was an ecosystem-level problem and concluded that the only feasible solution for solving a problem of this scale would be the development of a biocontrol agent — a natural predator against Sahara Mustard—that could be safely released into the environment of the southwestern United States to stop, and hopefully reverse, Sahara Mustard’s expansion and destruction of fragile habitat and biodiversity.

With the goal of discovering a biocontrol agent, we partnered in 2014 with researchers from the University of California, Irvine to map a course toward the discovery of such a biocontrol agent. This effort would make use of the latest genome sequencing technology to shave years and millions of dollars of cost off the project. The course we plotted is described in our White Paper titled “Seeking Biocontrols to Enable a Long-term Solution for Sahara Mustard (Brassica tournefortii) Invasion in North American Deserts.”

Phase I of the project began in 2015 and consisted of genomic sequencing hundreds of Sahara Mustard samples taken from throughout the southwestern United States. Completion of Phase I demonstrated three distinct populations of Sahara Mustard in the deserts of the Southwest, and thus three distinct introductions of this invader from the Old World. Phase I was the doctoral work of Daniel Winkler, Ph.D. and was published in Ecology and Evolution in June 2019 under the title “Multiple Introductions and population structure during the rapid expansion of the invasive Sahara Mustard (Brassica tournefortii).”

Dr. Winkler, in concert with colleagues at the USDA’s European Biologic Control Laboratory in Montpellier, France, are nearing the completion of Phase II of the project. Phase II involves the genomic analysis of samples of Sahara Mustard from its native range around the Mediterranean and into the Near East. Comparing the results of Phase II with those of Phase I will reveal exactly where in its native range the Sahara Mustard that was introduced into the United States in the early 1900’s came from. The importance of this discovery is that it will remove the guess work of where to look in Sahara Mustard’s enormous native range for potential predators already adapted to keep Sahara Mustard in check.

With the foundational work nearly completed, and with dozens of Parks, NGO’s, agencies, and academic institutions attesting to the importance of discovering a biocontrol agent for Sahara Mustard (, in June 2019 the USDA deemed Sahara Mustard to be a priority in its 2020-2025 Action Plan. Such a designation sets the stage for the third and final phase of our program: the identification of potential pathogen(s) and/or predators against Sahara Mustard from its native range, and the testing of these potential pathogen(s) and/or predators for safety and efficacy for future release in order to suppress the epidemic of Sahara Mustard in the deserts of the American Southwest.

While the identification and testing of potential pathogens against Sahara Mustard will take several more years, we are more than half way to our goal of discovering a way of confronting Sahara Mustard on an ecosystem level. None of this would have been possible without our brilliant and tenacious researchers and our generous supporters. I give my heartfelt thanks to everyone who has worked so diligently to get us this far. Please stay tuned and involved in the continuation of this important project!

J. David Garmon, MD
President, TCDC


Archive of TCDC Updates