San Benito County Weed Management Area

CURRENT PROJECTS

The Weed Management Area’s (WMA) work is concentrated in three main areas: Inventorying, Education, and Control.

Inventorying
In 2001, an extensive survey along the county roads was made to inventory the County’s weeds.  Armed with a GPS unit, a botanist covered 350 miles of County roads recording the types, density, and extent of noxious weed populations.  Road right-of-ways and areas near roads where focused on in this survey, as they often serve as introduction routes for new noxious weeds.  Using GIS, this data was converted to detailed maps, which were used to help determine what control activities should take place.

                                                   (Click on pictures for larger view.)
     Survey Truck                    GIS map                  

Education
The educational goal of the WMA is to organize educational programs and develop an awareness plan which focuses on educational needs, such as weed prevention, weed detection, weed control methods, weed biology, weed identification, weed economics, and environmental impacts.

Education Workshops– Every fall the WMA brings together a group of weed, livestock, range, and wildlife specialists to talk about their latest research projects and any changes in laws and regulations.  For information on attending a workshop contact Sergio Garcia, San Benito County Farm Advisor.

To See the agenda for the 2007 Workshop click here.

     
     Annual Workshop

Weed Control Studies – The WMA, along with UC Cooperative Extension and SBC Agricultural Commissioners staff, is participating in research projects to look at biological, holistic, and chemical systems for controlling weeds.  Studies on the biology of yellow starthistle have been completed and proper herbicide doses and timing for proper control have been established. (Contact Sergio Garcia, San Benito County Farm Advisor, for more information.)

Weed Identification – The WMA has identified 25 noxious weeds in San Benito County and has published a booklet entitled "Selected Invasive Weeds of San Benito County", with pictures and descriptions of each of the weeds.  Copies of this booklet are available free to San Benito County residents, contact the County Ag. Commissioner's office for a copy.  Supply is limited.

Control
Control work has focused primary on five weeds: Arundo, Yellow Starthistle, Purple Starthistle, Artichoke Thistle, and Scotch Thistle.


Yellow Starthistle
From the mapping conducted in 2001, it was found that there are still areas in the County that are relatively free from Yellow Starthistle (YST).  In these areas, where YST was found in small isolated patches, hand pulling was done.  It was also found that in many places YST occurs only within the road right-of-way and was not present in the adjacent rangelands. An existing San Benito County Public Works spray truck was equipped with a computerized rate controller and special nozzles to allow an entire road right-of–way to be treated with Translineâ.  Translineâ is a selective herbicide that provides specific control of YST.  Translineâ was applied in these areas to keep the YST from spreading into the adjacent range and open lands.

In areas where YST is firmly established biological control agents have been released in an effort to help manage it. Five different insect species that commonly feed on YST in the Mediterranean region have been introduced in the County.  One of these insects, commonly known as the Hairy Weevil, is collected in early summer from an established "nursery site" and redistributed to other areas in the County.  Biological control is a long-term project which will, hopefully, provide management of YST in the future.

                            
   YST weevil collection                YST Hairy Weevil


Purple Starthistle
The 2001 weed survey found extensive infestations of Purple Starthistle (PST) in the San Juan area, but only limited patches east of Hollister.  It was decided to start aggressive control work on these "pioneering" patches to keep this weed from spreading out of control in southern San Benito County.  In the spring of 2002, eradication work was started on the known PST patches found east and south of Hollister.  Herbicides were applied to the plants using a sprayer mounted on an Ag. Commissioner's 4X4 pickup.  Labor for the application was supplied by each landowner where the work was done.  Follow up control in these areas continues.

     
     PST spraying


Artichoke Thistle
Artichoke Thistle was found to occur in just a few areas in the County, making eradication of this weed possible.  At each infestation, personnel from the WMA survey the area.  The location where plants are found is recorded with a GPS receiver and the Artichoke Thistle plant is treated with Roundupâ.  If the plant has already formed a flowering seed head, the seed head is removed and packed out.  With the locations marked by a GPS unit, next season’s follow-up can be completed more efficiently.

                  
     NPS weed crew            Removing seed heads


Scotch Thistle
There are two known infestations of Scotch Thistle in San Benito County, which carries a category "A" rating by the State of California. This rating requires mandatory eradication.  Crews from County Agricultural Commissioner’s Office and the California Department of Food & Agriculture have been working on these infestations for several years.  Now, the County and State forces have been augmented with additional help from the other members of the WMA.  Personnel hike into the infested areas and any plants that are found are removed.  Their locations are recorded by a GPS unit to assist the follow-up efforts.


Giant Reed (Arundo donax)
Giant reed has been found in Tesquisquita watershed.  A joint project between landowners, RCD, SBCWMA, San Benito Ag. Commissioner, and NRCS was started in 2003 to remove the arundo.  Over 8 miles of arundo will be eradicated, from the headwaters at Arroyo de las Viboras all the way to Pacheco Creek.  Funding comes from RCD, SBCWMA, and Environmental Quality Incentives Program.  Over 21 cooperating landowners, represented by the Pajaro Watershed Working Group, are involved with this project.  Large clumps of arundo were cut by crews, stacked and burned. Herbicides were applied to the remaining stands of arundo.  Spot treatments of herbicides will continue until the weed is eradicated.  The map below shows the project location.

Location map of Arundo removal project.