Dodder-Susceptible and Resistant Plants

Dodder is a plant from a horror movie -- a parasite that uses fangs to suck the life out of its plant hosts

By M.L. Blue

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Upon finding a host, it sinks its fangs (known as haustoria) into the vascular system of its victim and drinks its water and nutrients. Dodder then grows and reattaches until it covers all nearby host plants in a tangled mat of orange stems. Dodder is an annual, and each plant produces thousands of seeds. The seeds remain viable in the soil for more than 20 years.

Young seedlings or plants attacked by dodder usually die. Mature plants are severely weakened, making them vulnerable to disease. Multiple species of field dodder (Cuscuta spp.) are wide-spread throughout the United States. Of particular concern are the infestations of Japanese dodder (C. japonica) found in Texas, California, South Carolina, and Florida. Dodder attacks both vegetable and ornamental plants, although not all plants are susceptible:

Dodder-Resistant Plants
All grasses (including grains such as corn)
Cool-season vegetables (e.g., lettuce, broccoli, cauliflower)
Many monocots (e.g., lilies, irises, palms, bamboos, orchids)
Soybeans
 

Dodder-Susceptible Plants

Beets
Carrots
Chrysanthemums
Garlic
Nightshade family plants (potatoes, eggplant, tomatoes)

    Here's how to deal with dodder:
  • Use certified weed-free seeds. (Contaminated seed was a major cause of dodder infestation until many states adopted laws that prohibit the presence of dodder seed in planting seed.)
  • Keep weeds controlled. Weeds such as field bindweed, lamb's-quarter, pigweed, and nightshade are hosts for dodder.
  • Remove any infestations before dodder goes to seed in late summer. Small areas can be cleared by hand; larger areas require mowing, pruning, or burning. The seed survives soil solarization.
  • If you have had a dodder infestation, replant the area with nonhost plants.
  • Spray serious dodder infestations with vinegar (acetic acid), but be aware that this destroys both dodder and the host plants.
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