Dodder Alert!
More about Dodder
The term “dodder” is used for more than 150 parasitic plants with yellow to orange twining stems that look leafless. (Actually, the leaves are tiny scales.) The flowers and seeds are small and easy to miss. Overall, the plants resemble threads or spaghetti, often tangled in masses that all but cover the host plants.
Generally, dodders are classified as being in the genus Cuscuta in their own family, Cuscutacaea. Some authorities, though, place some dodders in the genus or sub-genus Grammica , or place dodders in the family of morning glories ( Convulvulacaea ).
Dodders sprout from seed with a tiny root that soon withers away. They also can grow from pieces of the mother plant. Either way, the sprouting tips twine toward other plants – which they find at least partly by smell... more
Once they touch a host, they coil around it, and modified roots, called haustoria, both dissolve and physically break through the host's bark. When the parasite breaks through, it begins to suck water, minerals, and carbohydrates – everything it needs for life – from the host plant. More shoots twine toward other branches and other plants, until the plant and its neighbors are all but engulfed.
Dodders are found in many habitats, from seashore to desert – although not in frigid climates. The yellow to orange tangles have been given many names, often involving “devils,” “strangling,” and similar terms. Dodders also have had many benign uses in folk medicine -- for everything from dry and tired eyes to muscle pain, constipation, liver and urinary problems, and sexual health of both men and women.
California has a number of native dodders..more, most found in salt marshes or chaparral. Most are orange and threadlike, parasitizing low-growing plants or scrub. They co-exist in reasonable balance with other vegetation, without overwhelming their host plants. A few, though, join non-native dodders as pests of fruit trees and field crops from alfalfa and flax to onions, potatoes, beets, and melons, as well as garden plants. In addition to weakening these crops, dodders can spread diseases to some plants .
Why is Japanese dodder a special problem?
Japanese dodder, Cuscuta japonica , is native throughout much of Southeast Asia. It has round, fleshy stems of slightly greenish gold, about the thickness of angel-hair pasta (1-3 mm diameter). In cooler areas it dies back in winter, but in warm ones it can grow more or less continually.
Recently introduced into the United States, it quickly began causing problems in Southeastern states and California, where it was first seen in 2004. It has been found in more than a dozen California counties, particularly in the Central Valley and Bay Area. According to Cal-IPC it is an extremely threatening pest..more
Japanese dodder is on the federal government's Noxious Weed List ...more and importation of plants or seed capable of sprouting is illegal. The California Department of Food and Agriculture lists it as an “A” list weed...more
Japanese dodder spreads very quickly. It can grow several inches a day, forming huge masses reaching to treetops. It can move rapidly from plant to plant with the help of abundant seeds, water, and birds. Its popularity in Southeast Asian folk medicine also seems to be contributing to the spread.
Japanese dodder can infest a wide variety of plants, from groundcovers to very tall trees (click to see list ). This makes the orange tangles a threat to farms, gardens, and wild areas, particularly along or near water. It also makes the plant more difficult to eradicate.
What to do if you see Japanese dodder
The California Department of Food and Agriculture (CDFA) is asking help in locating Japanese dodder so that it can be eradicated. If you see Japanese dodder, please report the sighting to the CDFA at 1-800-491-1899 or to your county's Agricultural Commissioner...more
Generally, it is best to get CDFA help with eradication. Do not try to eradicate dodder with herbicides. If you must handle it, remove all infected branches, and generally the entire infected plant down to the roots. Carefully bag all fragments of the parasite and host and dispose of them in commercial landfills where you know they will be deeply buried. Do not compost either host or fragments. Keep a careful watch for new infestations in the general area for several years.
The San Francisco Estuary Project , California Invasive Plant Council (Cal-IPC), Friends of Five Creeks and Friends of Sausal Creek have published a flyer on the threat of Japanese dodder in English, Mandarin, Spanish, and Hmong. You may download and print those versions here.