Dodder [Cuscuta spp.][CDFA list: C] Photographs

Giant dodder [Cuscuta reflexa][Bayer code: none][CDFA list: A][Federal Noxious Weed] Photographs Map of Distribution

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SYNONYMS:angel’s hair, witch’s hair, tangle gut, strangle gut, devil’s gut, love vine, witch’s shoelaces.

GENERAL DESCRIPTION:Annual stem parasites with leafless, thread-like, orange, red, or yellow stems that twine over other plants. Dodder can be problematic in agricultural crops, especially alfalfa and tomatoes. In addition, dodder seed is difficult to exclude from commercial alfalfa, clover, or flax seed.

SEEDLINGS:Lack cotyledons. Develop a small temporary root to support a thread-like shoot, 4-10 cm long. Shoot moves slowly in a circular pattern as it grows until it touches a support. Upon contact with a suitable host, knob-shaped organs (haustoria) develop to penetrate the host stem. Seedlings die without a host within 10 days to several weeks depending on the species.

MATURE PLANT:Stems 1-2 mm thick, glabrous, lack leaves or have appressed, scale-like leaves about 2 mm long; red, yellow, or orange, but contain some chlorophyll and are sometimes tinged green. Growing stems branch and attach to new host stems with haustoria. Each dodder branch obtains nutrients from the host independent of older branches. One plant can cover 10-15 ft2.

ROOTS and UNDERGROUND STRUCTURES:Modified into specialized knob-shaped organs (haustoria) that penetrate host stems.

FLOWERS:Time variable depending on species, but generally May-October. Bell-shaped.

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FRUITS and SEEDS:Capsules spherical, ovoid, or conical; open irregularly or like a lid at the top (circumscissile). Seeds 1-4, spherical, oblong, ovoid, or angular.

POSTSENESCENCE CHARACTERISTICS:Frost kills plants, but haustorial tissue of some species can overwinter in host stems and develop new stems the following spring. Stems do not persist through winter.

HABITAT:Most natural communities, but sometimes infests nursery crops, landscaped sites, and agricultural crops, especially alfalfa, clovers, and tomatoes. Host range is broad, but monocots (excluding asparagus) are seldom affected.


PROPAGATION/PHENOLOGY:Reproduces by seed and vegetatively. Broken stems can develop new haustoria. Seed disperses by water, animal ingestion and movement, and especially human activities and machinery. A proportion of seed has a hard coat that must be weakened by scarification, microbial decomposition, and winter chilling before germination can occur. Germination does not require the presence of a host plant. Under favorable conditions, seed can germinate in the fruits. Seed can remain viable for at least 10 years in the soil. Emergence is typically from the top 5 cm of soil. In most years, the period of emergence ends by mid-May in the Central Valley.

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MANAGEMENT FAVORING/DISCOURAGING SURVIVAL:Many options are available to help decrease crop infestations. Useful methods include hand cultivation, spot or field burning, close mowing, later planting time (mid-May or later), and crop rotation to cereals or corn. Prevent the spread of dodder seed by thoroughly cleaning agricultural machinery immediately after it has been used in an infested field. Hand cultivation is most efficient at 30 days after planting a crop and repeated at 50 days.

SIMILAR SPECIES:Slender, twining, orange, red, or yellow stems easily distinguish this genus.


A thorough report of dodder control in seed alfalfa has been produced by Shannon Mueller through University of California Cooperative Extension, Fresno County. The report can be accessed on the World Wide Web at the following address:

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