The Japanese Dodder has most recently been found in Sacramento County, but has also been spotted in several other counties, including Los Angeles.  It’s long, spaghetti-like strands, with yellow flowers, hang from trees and shrubs and eventually kill the host plant.
Jay Van Rein with the state Department of Food and Agriculture says the weed is awfully hard to get rid of:
 
If they’re allowed to grow unabated, they can take over trees and shrubs, and it’s amazing how much they can grow just in a day or two. 

In the Asian community, the dodder’s seeds are thought to have medicinal properties, and officials believe that’s why someone first brought them into California. So far, the Japanese dodder has only been found in urban areas, but  officials fear it will spread to agriculture.