Japanese dodder is a very aggressive parasitic plant that has the potential of severely altering the composition and function of riparian areas, as well as affecting ornamental plantings and agricultural crops. It is an "A" rated noxious plant as classified by the California Department of Food and Agriculture (CDFA) and it is listed as a Federal noxious weed and as such is under an eradication program by the county department of agriculture. Japanese dodder looks very similar to thick diameter spaghetti noodles that are bright yellow-orange. It can completely engulf host plants and often drapes to the ground. It can kill large portions or the entire host plant within two to three years after infestation.
Japanese dodder was found for the first time in California in the summer of 2004 in Redding. In 2005 it was found in Contra Costa County by Dennis McLain, a pest detection trapper with the county. Dennis found it on two adjacent residential properties in San Pablo.
Fred Hrusa, the State botanist, visited the San Pablo and other sites in California. He found that, though a few small inconspicuous white flowers were found none had developed seed. It is believed that Japanese dodder is incapable of developing seed at least in northern California. The dodder may have been intentionally or unintentionally introduced through seed importation from Asia where Japanese dodder is believed to have medicinal value. It is legal to import heat treated sterile seed.
Japanese dodder is very different than our eight Bay Area native dodder species. These native dodders attack small plants like tomato, alfalfa, pickleweed and ceanothus. Japanese and other Asian dodders attack a wide variety of small plants and shrubs as well as a wide host of full grown trees including many of our native trees and fruit trees.
The Alameda-Contra Costa Weed Management Area (ACCWMA) is a group of agencies, growers and watershed volunteer organizations that was formed in 1998. Its focus is on noxious and invasive weed issues. Through the outreach efforts of ACCWMA Susan Schwartz of Friends of Five Creeks (a member group) recognized the Japanese dodder as a plant that she had been trying to identify. It was growing in Cerrito Creek on the Albany-El Cerrito boundary. This site was confirmed in early June 2006 as Japanese dodder by CDFA. The dodder was growing on California native willows and as well as on plum, thornless blackberry, and Algerian ivy at this site. It was also found by a creek group member in Wildcat Creek completely draping over a medium size California live oak and a California buckeye tree, two very important species of our native landscape environments.
CDFA mailed informational post cards to targeted areas of Contra Costa County. Through this and other outreach and detection efforts of our staff along with reports from conscientious citizens, 39 infested properties have been identified in Contra Costa County. It has been found in El Cerrito, Richmond, San Pablo, Pinole, Rodeo and Antioch.
Eradication involves removal of the entire host plant or all infested portions of the plant if is is newly-infested. Since Japanese dodder spreads vegetatively much care is taken to remove and clean up all fragments of dodder and to envelope infested material using plastic sheeting. The material is then transported by our department to a land fill where it is deep buried. This work is done by the Contra Costa County Department of Agriculture often with the help of CDFA. Most funding comes from CDFA's Emergeny Eradication Fund with a small portion coming from the county. After removal, infested properties are monitored for missed or recurring dodder until eradication can be declared.
Your help is needed! If you see this unique plant, please call our department at 925-646-5250 or the CDFA pest reporting hotline 1-800-491-1899.