Proposed Dates of Use: As conditions and time permit on October 24, 2022.
Street Address/Site Name: Wildhorse Agricultural Buffer
Location of Application Site: Spot-spray of individual plants throughout habitat areas.
Posting and Notification: Site notifications will be posted at least 48 hours before application via the pesticide application electronic notification system and at site entrances, remaining 24 hours after.
Pesticide: Telar (Chlorsulfuron2-Chloro-N-[(4-methoxy-6-methyl1,3,5-triazin-2-yl)aminocarbonyl])
Target Pests: Pepperweed
This herbicide use is justified due to the size of the site, size of infestation and growth stage of the existing weeds. The weeds reduce the amount of grass cover and therefore change the composition and structure of the habitat, reducing its value. Pepperweed also directly competes with milkweed, a native species that supports endangered Monarch Butterflies. A considerable investment was made to restore the site to native grasses in order to support resident and migratory wildlife and weeds threaten that investment.
Pepperweed is a management priority because it alters habitats and there is no reliable way to control it without herbicide. Mechanical cultivation or hand hoeing are not options because the plant can reproduce from vegetative material and these methods will actually increase the infestation. The plant can cause damage to infrastructure because it’s large, tuberous roots can undermine pipes, foundations and other facilities.
There is no reliable way to kill these weeds using non-chemical methods at the scale they exist on the site. Other than the reasons mentioned above, mechanical cultivation is not an option because the soil disturbance will hurt or kill the native grasses. Exposing soil could also allow for more weeds over time. Additionally, the resources to go through the treatment area and hoe or hand-pull each plant to kill it and prevent seed set are not available. Open Space does not have access to the amount of labor needed to do this, plus the amount of soil disturbance would be similar to mechanical cultivation.
More information on the IPM Program, including the current Policies and Procedures guidance, can be found on the City's webpage: Integrated Pest Management
