Dodder

Cuscuta species

Family: Convolvulaceae (was Cuscutaceae)

Names:

Cuscuta is from the Arabic word meaning "to bend" and refers to the twining habit of the stems. Dodder is from the German word for "egg-yolk" and refers to the yellow stem colour of many of the species.
Australian Dodder (Cuscuta australis)
Fringed dodder (Cuscuta suaveolens) not in WA.
Golden Dodder (Cuscuta campestris)
Greater Dodder (Cuscuta europaea)
Lesser Dodder (Cuscuta epithymum)
Small-seeded Alfalfa Dodder (Cuscuta planiflora)
Tasmanian Dodder (Cuscuta tasmanica)
Cuscuta victoriana.

Other names:

Beggar Vine
Love Vine
Strangleweed.

Summary:

Dodders are leafless, thin stemmed plant parasites that usually have little or no chlorophyll. They twine around the host plant and attach suckers (haustoria) to remove nutrients from the host.

Description:

Cotyledons:

Two. Rudimentary or none.

Leaves:

None or inconspicuous scales.

Stems:

Yellow, green or pink. Twining. Many branched. Attach to host plant by small suckers (haustoria) to obtain moisture and nutrients. Thread like. Up to 1000 mm long.

Flower head:

Clusters of flowers along the stem.

Flowers:

White, cream or pink. Bell shaped. 3-4 mm round.

Fruit:

Globular capsule. 3-4 mm round with 1-4 seeds. Opens by an irregular line around the middle.
Seeds: Brown, yellow or grey. Globular but flattened on one side. 1- 2 mm round. Rough seed coat. Triangular pyramid shaped.

Seeds:

Small.

Roots:

None or very small. Dies away after stem attachment.

Key Characters:

Thin, leafless, twining, brown to yellow stems.

Biology

Life cycle:

Annual. (Golden dodder can be perennial). Seeds germinate mainly in spring but through to autumn. Seedlings have no roots and soon die unless they contact the stem of a suitable host plant to parasitise. Twining stems engulf the host plant quickly. The first seed may be set within 3 weeks. Flowering and seeding may continue over an extended period so dodder seed may be harvested with the crop. Seed may survive in the soil for at least 5 years. Most spread is by seed as a contaminant of produce or in water or by passing in animal droppings. Stem fragments can move in water or on machinery and invade new hosts. Large amounts of seed are produced. 16,000 seed have been counted on one plant.
Mature plant is a twining, yellow to pink stemmed parasite, with white to pink bell shaped flower and globular fruit.

Physiology:

Parasite.

Reproduction:

By seed and stem fragments.

Flowering times:

Most of the year.

Seed Biology and Germination:

Survives in soil for at least 5 years.

Vegetative Propagules:

Stem fragments/

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Origin and History:

Australian or overseas, depending on species.

Distribution:

ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Various species occur in each state.

Habitats:

Grows wherever host survives.

Climate:

Soil:

Not dependent on soil type.

Plant Associations:

Significance:

Beneficial:

Detrimental:

It will parasitise various plants depending on the species of Dodder. Can seriously reduce the yields of vegetables, Lucerne, clovers and a number of wildflowers and ornamentals. They can transmit viral diseases of some plants.

Toxicity:

Infested fodder may cause scouring and cattle deaths have been recorded overseas, but don't seem to occur in Australia. It is relatively unpalatable.

Symptoms:

Scouring.

Treatment:

Prevent stock access to infested areas or fodder.

Legislation:

Noxious weed of NSW, SA, TAS, VIC, WA.

Management and Control:

Burn after spraying with diesel and/or cultivate. The herbicide diquat, amitrole and glyphosate can be used if applied before flowering. Repeat sprays are required. Metsulfuron, clopyralid and propyzamide have more selective action. Fumigation with chlorinated hydrocarbons is effective and expensive. Methyl bromide is ineffective. Various mulches provide some control in perennial or transplanted crops. A number of biocontrol agents have been investigated and a fungal preparation is used on soybeans.

Thresholds:

Eradication strategies:

Remove host plants for 3 to 5 years. Growing crops or pasture species that are not attacked by the particular Dodder usually does this.
For Golden dodder, grass pastures or crops such as the cereals are normally used. Good control of broadleaf weeds in these crops is essential to stop Golden Dodder surviving. In areas that can't be cropped, application of picloram based herbicides provides residual control of broadleaf plants with little effect on grasses. Patches can be treated by spraying host plants, plus a 5 metre buffer area, until just wet, with a mixture of 1 litre of Grazon plus 250 mL Pulse® Penetrant per 100 litres of water. Repeat this annually for five years or when broadleaf plants germinate.

Herbicide resistance:

Biological Control:

Related plants:

Australian Dodder (Cuscuta australis)
Fringed dodder (Cuscuta suaveolens) not in WA.
Golden Dodder (Cuscuta campestris)
Greater Dodder (Cuscuta europaea)
Lesser Dodder (Cuscuta epithymum)
Small-seeded Alfalfa Dodder (Cuscuta planiflora)
Tasmanian Dodder (Cuscuta tasmanica)
Cuscuta victoriana.

Plants of similar appearance:

Dodder Laurels (Cassytha species) are native plants and usually grow on native hosts, usually have at least some green on their stems, are rarely as golden as Golden Dodder, have 3 petals rather than 5 lobed flowers and tend to be perennial.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P156. Photo.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P559-560. Photo.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #387.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia).

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne).

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.