Skip to main content
ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #371352

Research Project: Watershed-scale Assessment of Pest Dynamics and Implications for Area-wide Management of Invasive Insects and Weeds

Location: Invasive Species and Pollinator Health

Title: Invasive alligator weed (Alternanthera philoxeroides) expands range in northern California: Feather River populations

item CARTER-ERVIN, ROBIN - California Department Of Water Resources
item Grewell, Brenda
item Futrell, Caryn
item REICHOLF, REBECCA - University Of California, Davis

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/23/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Alligator weed (Alternanthera philoxeroides) was discovered in the Suisun Marsh in late 2017. This population was the first in Northern California, and in 2018 several population patches were found in the lower Sacramento River and the Delta. Potential upstream source populations were unknown. In 2019, several new infestations of alligator weed have been discovered along a 23-mile section of the Feather River, from about 7 miles south of the Oroville Dam south to the city of Live Oak. The densest patch observed is near the Feather River Outlet Boat Ramp just south of Oroville, CA. So far, a total of 44 locations have been mapped within the Feather River and it is assumed that there are many more. Alligator weed has a High Cal-IPC rating and an A CDFA Pest Rating. It spreads rapidly by clonal shoot fragments to invade lakes, streams, canals, ponds, and irrigation ditches and is has a high growth rate. A rapid management response is needed to reduce negative impacts on flood conveyance, water deliveries, and endangered species habitat.