Proposed Dates of Use: As conditions and time permit on August 8,2023
Street Address/Site Name: South Fork Preserve, around newly constructed overlook feature
Detailed Location of Application Site: Included above.
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 Products: Vastlan; Round Up Custom; Triclopyr choline: 2-[(3,5,6-trichloro-2-pyridinyl)oxyacetic acid, choline salt; Round Up Custom (Isopropylamine salt of glyphosate) EPA Reg #: 62719-687, 524-343 Pesticide Type: Herbicide City Use Type: Tier II Limited-Use, more restrictive - Vastlan, Tier 1, most restricted, may not be used in areas with high public use – Round Up Custom
Justification for Use: This herbicide use is a follow-up from an initial application conducted last October. The application is justified due to size of infestation and proximity to new infrastructure. The Open Space program completed a grant funded trail construction project and the target stand of blackberry threatens the integrity and usability of the features over time. The current infestation is largely a result of changing conditions from the construction. The blackberry is spreading due to low flows in Putah Creek, as well as disturbance from the construction project. The conditions present an opportunity to access and control the stand to prevent conflicts in the future and help re-establish native plants in the area.
Himalayan blackberry is highly invasive species that can completely transform landscapes and consume structures if left unchecked. The species grows larger and denser than native blackberries, out-competing all native species. They can also grow up and through structures, making them inaccessible to users with thick, spiked canes. This target species is a perennial vine, and grows from seed, from root rhizomes and by broken vegetative materials. These strategies make the species hard to control. Mechanical control or pruning can actually spread the infestation unless all biomass is completely removed from site, and this is nearly impossible to ensure. New vines will grow from large roots underground and cannot be dug out from a delicate creek bank near concrete footings.
To achieve control, we will use targeted application of approved herbicides via backpack sprayers. We must spray exposed vegetation to ensure maximum uptake of the herbicides. The timing of the application late in the growing season will help ensure the plant translocates the chemicals to its significant root structure. Professional applicators will take care to avoid overspray on existing native species.
All work will be done in coordination with the City’s Wildlife Biologist to ensure no impacts to avian or other species.
More information on the IPM Program, including the current Policies and Procedures guidance, can be found on the City's webpage: Integrated Pest Management
