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Dodder, an annual
plant that consists of thin thread-like stems that are orange in
color which attach to a host plant, belongs to the dodder (cuscutaceae)
family, which includes many species. At one time dodder was classified
in the morning glory family. Dodder is a true parasitic plant. Unlike
other parasitic plants such as mistletoe, which have green leaves,
only extract water and nutrients from host plants. Dodder has no
leaves and must extract carbohydrates from the host plant. |
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Dodder produces small clusters of white to pink flowers in the early summer. Dodder spreads primarily by seeds which have the capability of surviving in the soil up to sixty years. When dodder seed germinates, establishment is dependent upon host plant availability. If a host plant is not within 1 - 3 inches of the initial germinating seed the seedling will die. When the dodder seedling emerges, it develops a small ineffective root which can support the seedling for only a couple of days. Upon germination, the small dodder seedling sways around in search of the host plant. When a host plant is contacted, the dodder coils around the host in a counter-clockwise direction. Small sucking appendages called "haustoria" are produced that penetrate the host plant and extract food. Once the haustoria begin to extract food, the small initial root dies. Dodder can grow up to 3 inches per day and continually produces new haustoria to drain the host plant of nutrients. Dodder is found throughout North America. |
| Integrated Pest Management Control Recommendations: |
Cultural Practices:
Dodder is best controlled through establishment prevention by using clean
seed. Ornamental beds should be kept clean of seed-producing plants. Once
dodder becomes established, eradication is almost impossible. Mechanical
removal can be attempted, but once dodder has produced the haustoria it
is near impossible to avoid damage to the host plant. If dodder has germinated
and has attached to a host plant, removal of both is recommended to eradicate.
Herbicide
Use:
Use of pre-emergent herbicides is the best chemical approach. These products
must be applied prior to the germination of the seed as the small seedling
root will drop off once the haustoria has formed. Dinitroanaline herbicides
have been reported to be effective. Dichlobenil has also shown good results.
Read all labels to ensure that the herbicides can be used around the host
plants. Glyphosate has shown results as a postemergent herbicide, but
its use is limited as it will also damage the host plant. Phenoxy herbicides
have only shown limited control and again injury to the host plant can
occur.
University Links | Gordon's Recommendations | Germination Dates
