Carrot (Daucus carota)-Dodder

Cause Annual, parasitic seed plant belonging to the genus Cuscuta, which lives on carrots and other plants including commercial crops and weeds. Dodder plants consist of rootless, leafless stems that encircle and penetrate carrot stems, diverting host nutrients. Dodder is favored by high temperatures and full sunlight. Dodder seed can remain viable in the soil for 20 years. Dodder seed are gray to brown in color, irregularly round with a rough surface texture, and are similar to clover and alfalfa seed in size.

Symptoms A tangle of leafless, thread-like stems that are yellow, orange, purple, or white entwine carrot petioles. Tiny white, pink, or yellowish flowers in clusters appear in June; seeds are produced from midsummer until frost kills the plant.

Cultural control See also the PNW Weed Management Handbook for additional information.

  • Plant seed free of dodder seed.
  • Do not use manure with dodder in it.
  • Do not graze animals in dodder-infested areas and then put them on clean land.
  • Avoid spreading dodder seed in irrigation water.
  • Cut dodder-infected plants before dodder plants develop seeds.