Dodder infection.
Dodder, Cuscuta sp. infecting carrots. [Click for larger image]	Dodder, Cuscuta sp. close-up of flowers. [Click for larger image]

This plant is a real sucker!

Dodder is a parasitic vine with smooth, wiry, twining stems that attach to a host plant with tiny suckers (haustoria) which draw water, minerals and carbohydrates out of the host plant to feed itself. Large numbers of them twine over shrubbery to form blankets that look like masses of orange spaghetti (which gives it its common name, "vegetable spaghetti"). Dodder is a member of the Morning-Glory Family (Convolvulaceae) in older references, and a member of the Dodder Family (Cuscutaceae) in the more recent publications and lacks sufficient chlorophyll in its buds, fruits and stems to manufacture food for itself, thus its "sap-sucking" ways.

Identification

Only dodder seedlings have roots, its tangled stems are usually orange, but may be yellowish, whitish, or greenish or even tinged with red or purple. The plant's tiny leaves are scale-like and almost invisible, whereas the numerous clusters of little waxy cream colored 5-petaled flowers and subsequent 1/8" seedpods are more noticeable. There are 2 to 4 3-sided brownish seeds in each 2-celled capsule.

The USDA classifies dozens of dodder species as Noxious Weeds. American dodder (C. americana) and golden dodder (C. campestrisis) are particularly damaging agricultural weeds. Dodder is a major problem for such crops as alfalfa, clover, and flax. Other plants commonly parasitized by dodder include many daisy relatives (especially chrysanthemums), Virginia creepers, trumpetvines, English ivies, petunias, camellias, citrus, beets, redbuds, hollies, sumacs, buttonbushes, cucumbers, raspberries, potatoes, tomatoes, roses, coleus, impatiens, and various legumes. Dodder can also carry plant viruses, including Phytoplasma, which is responsible for many of the "yellows" diseases.

Culture

Dodder is usually regarded as an annual, but tends to be a perennial in Florida. Some species are salt tolerant and/or herbicide resistant.

Light: Dodders grow most vigorously in full sun.

Moisture: Moisture requirements vary according to host plant. Some species grow in marshes, others in arid scrub-lands.

Hardiness: USDA Zones 4 - 11.

Propagation: Dodder reproduces readily from seed. A single plant may produce thousands of seeds, which can remain viable in the soil for many years.

Control

Its wide host range and the long life of its dormant seeds make dodder hard to control and nearly impossible to eradicate. Dodder seed can be spread by irrigation water, in the manures of livestock that have eaten infested alfalfa, or along with the seed of crops that were infested with dodder. Pre-emergent herbicides such as DCPA (Dacthal), applied to the soil in the spring prior to seed germination will prevent this pest. Follow label directions!

 Pulling and destroying dodder infected plants is recommended. Dodder must be destroyed before it produces seeds or infestations will spread. Once established, dodder appears in patches in the field. Cutting the host plant prior to the dodder producing seed helps reduce the quantity of seed for the following year. Planting an infested field with an immune or resistant crop such as cereals, corn, soybeans, velvetbeans or cowpeas assists in control. 

The use of a 2,4-D type herbicide or contact herbicide directed at infected hosts and dodder plants is effective in killing established parasitic plants (as well as the host).