Cooperative Extension Service
The University of Georgia College of Agricultural and Environmental Sciences
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Dodder (Cuscuta spp.)
Can I Control It?

Mark Czarnota, Ph.D., Ornamental Weed Control Specialist
Department of Horticulture, 1109 Experiment Street
Griffin, GA 30223

Dodder (Cuscuta spp.) is a parasitic weed that infects a wide range of herbaceous and woody plant material. There are approximately 12 species of dodder, and each species has a different host range. Dodder is generally brought into ornamental planting via infected plant material.

Growth Characteristics

Dodder is a rootless, leafless, parasitic flowering plant. It is in the morningglory (Convolvulaceae) family. Dodder flowers and produces seed like any other flowering plant. Seeds can remain dormant in the soils for years before germinating. Under the right conditions, dodder seed will germinate, sending up a tendril that attaches to a suitable host plant. If no suitable host is available, the plant will die within a few days. Dodder attaches itself to the host plant's vascular system with a peg-like haustoria. Once attached, the root system of the dodder plant shrivels, and the plant feeds off the host. Dodder contains no green tissues because it does not need to photosynthesize and produce its own food. The stem color of dodder is generally yellow to orange, but can also be shades of red or white. Flowers are small, white or pink and usually born in clusters.

Host Plants

Dodder infects a wide range of plants, including plants in the Asteraceae family (chrysanthemums, marigolds and sunflowers), Fabaceae family (alfalfa, clovers, soybeans and vetches), and the Ericaceae family (azaleas and rhododendrons).

Control

Remove all plants or portions of plants infected by dodder. Ideally it should be removed before the dodder flowers and produces seed. To date, dodder cannot be controlled through a selective postemergent herbicide application. However if the host plant is killed, the dodder plant will also die. Dodder seed can be controlled with the preemergent herbicides Kerb and Casoron (check label to see if herbicides are safe to host ornamentals). Other options include soil sterilization with Basamid (a soil sterilant).

Trade and brand names are used only for information. The Cooperative Extension Service, University of Georgia College of Agricultural and Environmental Sciences does not guarantee nor warrant published standards on any product mentioned; neither does the use of a trade or brand name imply approval of any product to the exclusion of others which may also be suitable.

Attention!

Pesticide Precautions

• It is the responsibility of the pesticide user to observe all directions, restrictions and precautions on pesticide labels. It is dangerous, wasteful and illegal to do otherwise.
• Store all pesticides in original containers with labels intact and behind locked doors. KEEP PESTICIDES OUT OF THE REACH OF CHILDREN.
• Use pesticides at correct label dosage and intervals to avoid illegal residues or injury to plants and animals.
• Use pesticides carefully to avoid drift or contamination of non-target areas.
• Surplus pesticides and containers should be disposed of in accordance with label instructions so contamination of water and other hazards will not result.
• Follow directions on the pesticide label regarding restrictions as required by State or Federal Laws and Regulations.
• Avoid any action that may threaten an endangered species or its habitat. Your county extension agent can inform you of endangered species in your area, help you identify them and, through the Fish and Wildlife Service Field Office, identify actions that may threaten endangered species or that habitat.

Circular 876-6/May, 2004

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service, the University of Georgia College of Agricultural and Environmental Sciences offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.

Gale A. Buchanan, Dean and Director