New pest parasite, Cuscuta japonica or Japanese dodder
A new pest parasite, Cuscuta japonica or Japanese dodder, has been found invading the East Bay. Please be on the lookout and inform your county agriculture office if you see it.
The leafless, bright-yellow parasitic vine forms dense tangles on willows, blue elderberry, and wild plums on Cerrito Creek, on the Albany-Contra Costa border. Friends of Five Creeks, a volunteer creek-restoration group, reported the infestation after seeing an Alameda/Contra Costa Weed Management Area alert. There are many native and non-native California dodders, but no other forms thick, twisted, bright yellow mats in broadleaf trees and shrubs. This dodder is capable of parasitizing many hosts.
The two previous California reports were on orchard trees in the Central Valley and pittosporum at an apartment building in San Pablo. There is a Department of Agriculture quarantine against importing plants or viable seed. But the rules are weak. Vince Guise of the Alameda/Contra Costa Weed Management Authority reports that seed from a recent, supposedly sterile shipment, imported as herbal medicine, were found to sprout readily.
Plants spread both by seed and vegetatively. Once the sticky seed, or the long, twisting growing tip, finds a home, it sends root-like hausatoria into the host’s limbs, sucking out water and nutrients.
Plants should be handled and disposed of with extreme caution. The Weed Management Area recommends that you contact them for removal rather than doing it yourself. If you do work on the parasite, their recommendation is removal of the entire tree or shrub down to the ground, careful double bagging of all debris, and disposal where nothing could possibly take root (buried in landfill with good soil cover, not composted).
In Alameda or Contra Costa Counties, contact Vince Guise, vguis AT ag DOT cccounty DOT us.
(Please also let me know if you find it in the Sausal Creek watershed!)
– Karen