Web Content Display Web Content Display


Strategy A3: Control Weeds and Other Pests           
Strategy A3.2:  Prioritize weeds and other pests for area-wide control


This strategy would provide technical assistance to Delta farmers, residents, marina operators, boaters, and others affected by terrestrial and aquatic weeds to inventory, prioritize, coordinate, and implement weed management projects. This strategy could also be extended to management of other pest species.

There are 130 known CDFA-rated noxious weeds and Cal-IPC-listed invasive plant species in the Delta. Actions could be designed to perform risk assessment and subsequent prioritization of treatment areas to strategically and effectively reduce expansion of the multiple species of weeds. Actions could include creation of an early detection network and reporting system. Tools to help identify suitable candidate weeds and populations for management include CalWeedMapper (http://calweedmapper.cal-ipc.org/) and WHIPPET (Weed Heuristics: Invasive Population Prioritization for Eradication Tool) (http://whippet.cal-ipc.org/).

CalWeedMapper (http://calweedmapper.cal-ipc.org/) is an online tool that enables natural resource managers to identify management opportunities in a region of interest. WHIPPET (http://whippet.cal-ipc.org/) is a decision-making tool to help prioritize weed populations for eradication. Used together, these tools can help land managers systematically target weed infestations by putting their limited resources into populations known to cause the greatest impacts, are most likely to spread, and are most feasible to eradicate.

As proposed in Strategy A3.1, Reinvigorate County Weed Management Areas, treatments could then be done through contracts with the landowner through the local Weed Management Areas to treat on private land or contracted with the California Conservation Corps for work on public-owned land.  

This ALS strategy, in concert with Strategy A3.1, would complement the efforts of the Department of Boating and Waterways on aquatic weeds by addressing additional terrestrial weeds that are problematic for agriculture, and often for native vegetation communities as well.


The California Department of Fish and Wildife maintains the California Aquatic Invasive Species Management Plan (http://www.dfg.ca.gov/invasives/plan/), which proposes management actions for addressing threats focused on non-native algae, crabs, clams, fish, plants, and other species that continue to invade California's creeks, wetlands, rivers, bays, and coastal waters.

The California Department of Food and Agriculture (CDFA) designates plant species as noxious weeds and maintains a noxious weed list per the California Food and Agricultural Code and Title 3 of the California Code of Regulations. When listed as noxious, each weed receives a rating based on its statewide importance as a pest, the likelihood that eradication or control efforts would be successful, and the present distribution of the weed in the state. CDFA uses the noxious weed list to prioritize weed control and eradication throughout the state.

Under the Aquatic Weed Control Program, the Department of Parks and Recreation's Division of Boating and Waterways (DBW) (http://www.dbw.ca.gov/) is the lead state agency responsible for the control of Brazilian waterweed, water hyacinth, and South American spongeplant in the Delta, its tributaries, and Suisun Marsh. DBW is bound by permit conditions and prioritization systems that dictate when and where control activities may occur.

The Delta Conservancy in cooperation with the Department of Water Resources is testing a pilot program that will likely lead to a Delta-wide Arundo Control Program.
The Delta Plan has a policy and a recommendation related to nonnative invasive species. Ecosystem Restoration Policy ER P5 (23 CCR section 5009) states:

(a) The potential for new introductions of or improved habitat conditions for nonnative invasive species, striped bass, or bass must be fully considered and avoided or mitigated in a way that appropriately protects the ecosystem.

(b) For purposes of Water Code section 85057.5(a)(3) and section 5001(j)(1)(E) of this Chapter, this policy covers a proposed action that has the reasonable probability of introducing or improving habitat conditions for nonnative invasive species.

Ecosystem Restoration Recommendation ER R7 states:

The California Department of Fish and Wildlife and other appropriate agencies should prioritize and fully implement the list of "Stage 2 Actions for Nonnative Invasive Species" and accompanying text shown in Appendix J taken from the Conservation Strategy forRestoration of the Sacramento–San Joaquin Delta Ecological Management Zone and theSacramento and San Joaquin Valley Regions (DFG 2011). Implementation of the Stage 2 actions should include the development of performance measures and monitoring plans to support adaptive management.

The DWR Central Valley Flood System Conservation Strategy update for 2017 will include an Invasive Plant Management Plan. 

DWR Operations and Maintenance Aquatic Nuisance Species Program focuses on invasive pests in State Water Project facilities, but also has done work on arundo removal on land purchased for mitigation and funds CDFA to survey for hydrilla in the Delta and to eradicate it from Clear Lake and other water bodies connected to the watershed. 

Weed managers may also consider the National Park Service Exotic Plant Management Program (http://www.nature.nps.gov/biology/invasivespecies/EPMT_teams.cfm) as a model for forming strike teams to assist landowners to respond swiftly to protect their land from invasive plants.


Farmers may not be familiar with Cal-IPC, CalWeedMapper, and WHIPPET and how these partners and tools are beneficial.

Currently, DBW, the only entity authorized to use herbicide to treat Brazilian waterweed, water hyacinth, and South American spongeplant in the Delta, is required to operate under two Biological Opinions (USFWS and NMFS) and the Central Valley Regional Water Quality Control Board's National Pollutant Discharge Elimination System (NPDES) permit. NPDES permits are required for all aquatic pesticide applications in California. 

Securing adequate funding and resources for aquatic weed control is also an issue.  The DBW program is expensive, and non-chemical treatments (e.g., mechanical harvesters) are also expensive, time-consuming, or hard to implement/coordinate with residents and agencies.

Identifying and coordinating with existing efforts to manage pest species would maximize efficiency.


Resource Conservation Districts (RCDs) (http://www.carcd.org/) implement various types of conservation projects on public and private lands and educate landowners and the public about resource conservation.  Project activities conducted by the RCDs include, but are not limited to, agricultural land conservation, wildlife habitat enhancement, and wetland conservation.  Weed managers could consider engaging the RCDs in helping to educate farmers about invasive species and the benefits of removal as well as provide technical assistance to identify weed populations and prioritize control or eradication on agricultural land. 

The Bay area has established a Bay Area Early Detection Network (BAEDN) (http://www.cal-ipc.org/WMAs/BAEDN/). BAEDN is a collaborative partnership of regional land managers, invasive species experts, and concerned citizens in the nine-county San Francisco Bay Area which selects regional priority species for eradication, including some naturalized non-native plant species that have not yet become invasive but that are deemed to be a future risk. BAEDN has become a project of Cal-IPC, joining with other regional partnerships across the state working with Cal-IPC to prioritize eradication targets. Cal-IPC is supporting continued work on Bay Area populations that have been selected for eradication. BAEDN used WHIPPET to prioritize populations of target weed species. This program could serve as a model for a similar program in the Delta.

Other potential partners include:

If you would like to provide feedback on this strategy, please click the following link: Agricultural Stewardship Strategy Feedback Form

ALS Workgroup: ALS Framework and Strategies: Section II:  Strategy A3.2 Prioritize weeds and other pests for area-wide control: 061014