SafePlants

Alfalfa Dodder (Cuscuta approximata)

Alfalfa dodder, scientifically known as Cuscuta approximata, is a parasitic plant with a significant impact on agricultural systems, particularly alfalfa and clover crops. It is also referred to as smallseed alfalfa dodder and smoothseed alfalfa dodder.

Considerations for Pets

• Several weed species found in California alfalfa fields are poisonous to livestock. Alfalfa dodder (Cuscuta campestris) toxicity has been reported in horses.
• Dodder seeds are small, gray to brown, irregularly round with a rough surface texture.

Taxonomy and Nomenclature

• Scientific Name: Cuscuta approximata Bab.
• Common Name: Alfalfa dodder
• Family: Not explicitly mentioned in the text.
• Synonyms:
  • Cuscuta approximata var. urceolata (Kunze) Yunck.
  • Cuscuta suaveolens syn C racemosa C racemosa var chileana (German-English Dictionary)
  • smooth-seed alfalfa dodder: Cuscuta approximata Babington var. approximata

Distribution and Habitat

• Native to Eurasia and Africa.
• Also found in North America.
• Global Range: Great Plains species, found from Illinois to South Dakota and from Florida to California, as well as Mexico.

Ecological Role

• Parasitic plant, damaging to leguminous crops (alfalfa, clover).
• Impacts vegetable, forage crops, ornamentals, and native plants.
• Considered a noxious weed in many parts of North America.
• Can kill host plants in severe infestations, reducing alfalfa yield.
• C. epithymum, another dodder species, poses a risk of accidental introduction with contaminated materials.

Morphological Characteristics and Growth Habits

• Annual, parasitic seed plant.
• Leafless, thin-stemmed.
• Stems twine around the shoots of host plants.
• Leaves reduced to minute scales on a glabrous stem.
• Forms small appendages to attach to the host plant.
• Rootless plant that attaches to its host soon after germination.
• Dodder stem color is sometimes yellow, reminiscent of egg yolk.
• Dodder seeds are gray to brown, irregularly round with a rough surface texture

Interactions with Other Organisms

• Parasitizes various kinds of wild and cultivated plants, including alfalfa, lespedeza, flax, clover, potatoes, asparagus, melons, safflower, sugarbeet, and tomato.
• Host plant: Alfalfa (Medicago sativa).

Resources and Further Information

• UC home and landscape guidelines for control of Dodder.
• Washington Noxious Weed Law.
• USDA PLANTS Database (CUAP2).
• Discover Life page.
• Montana Field Guide (for photo submissions).
• ITIS (Integrated Taxonomic Information System).