Dodder-A Parasitic Seed Plant
Gail Ruhl, Sr. Plant Disease Diagnostician,
Department of Botany
& Plant Pathology, Purdue University
Dodder (Cuscuta spp.) is a twining
plant that obtains its moisture and nourishment by parasitizing
various kinds of wild and cultivated plants. The seedlings must
attach to a suitable host within a few days of germinating or
they die. Once the Dodder seedling finds a plant, it quickly
twines itself around the plant's stem and the basal part of the
parasite soon shrivels away so that no soil connection exists.
Its water, minerals and carbohydrates are absorbed from the host
plant through haustoria, specialized absorbant organs that press
up against the stem of the host plant , penetrate the tissue
and act as “straws”.
Dodder rarely kills its host plant, although it may stunt its growth.
Dodder flowers are numerous and are borne in tight balls or in
a loose cluster (depending on species). The fruit is about
1/8 th inch in diameter, with thin papery walls and contain 1 to
4 seeds. These seeds drop to the ground and germinate the
next growing season if a suitable host is present. If no
suitable host is present, the seed may remain dormant for five
Its wide host range and the long life of its dormant seeds make
dodder hard to control and nearly impossible to eradicate. There
is no herbicide that can be applied to garden and/or landscape
plants once the dodder is up and growing on plants. Hand-pulling
and pruning is the only method of control once the dodder is established.
Pulling and destroying dodder infected plants before it produces
seeds is recommended. Prior to germination, dodder can be
prevented reasonably well with the application of a pre-emergence
herbicide. Be sure to read and follow all label directions before
using any pesticide.
Colorado State University Cooperative Extension
Click image to enlarge
Dodder on a pepper plant
Photo courtesy of Lorraine