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.
Golden Dodder is a parasitic, leafless, vine with thread-like yellow to orange stems that twine around the host plant and attach by suckers (haustoria) to remove nutrients. The tiny, white to cream flowers are in dense clusters. Each flower (only 2-4 mm long) is bell-shaped, 5-lobed and has 5 stamens. The fruit is globular.
Native to North America, this weed can be a problem smothering vegetation near Albany and Pemberton and is a declared weed. It is a serious weed of vegetables and been recorded as a parasite on both introduced and native plants especially Muehlenbeckia adpressa.
Rudimentary or none.
None or inconspicuous scales.
Golden yellow. Twining. Many branched. attach to host plant by small suckers (haustoria) to obtain moisture and nutrients. Thread like. Up to 1000 mm long.
Clusters of flowers along the stem.
White or cream. Bell shaped, 5 lobed. 3-4 mm round.
Globular capsule. 3-4 mm round with 1-4 seeds. Opens by an irregular line around the middle.
Small, brown, yellow or grey. Globular but flattened on one side. 1- 2 mm round. Rough seed coat. Triangular pyramid shaped.
None or very small. They die away after stem attachment.
Thin, leafless, twining, brown to yellow stems.
Annual or rarely 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.
Mainly summer with some flowers at all times of the year.
Seed Biology and Germination:
Seed usually germinates after rain.
Population Dynamics and Dispersal:
Spread by seed and stem fragments.
Produces very large numbers of seeds.
Origin and History:
ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Grows wherever host survives.
Any soil type.
Associated mainly with introduced plants.
Used experimentally to transmit viruses.
It will parasitise various plants. Can seriously reduce the yields of vegetables, Lucerne, clovers vetches, legumes and a number of wildflowers and ornamentals. They can transmit viral diseases of some plants.
Infested fodder may cause scouring and cattle deaths have been recorded overseas, but don't seem to occur in Australia. It is relatively unpalatable.
Prevent stock access to infested areas or fodder.
Noxious weed of NSW, SA, TAS, VIC, WA.
Management and Control:
Burn host plants 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.
Very low because it spreads so quickly on preferred hosts.
Manual removal is a waste of time and usually spreads the Golden Dodder.
Remove host plants for 3 to 5 years. Grow species that are not attacked by Golden Dodder such as grass pastures, cereal crops or woody species. Good control of broadleaf weeds in these crops is essential to stop Golden Dodder surviving. In areas that can't be cropped or replanted, 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 when the hosts are actively growing. Repeat this annually for five years or when broadleaf plants germinate.
Replant woody native species in bushland areas.
Australian Dodder (Cuscuta australis)
Fringed dodder (Cuscuta suaveolens) not in WA.
Greater Dodder (Cuscuta europaea)
Lesser Dodder (Cuscuta epithymum)
Small-seeded Alfalfa Dodder (Cuscuta planiflora)
Tasmanian Dodder (Cuscuta tasmanica).
Plants of similar appearance:
Cuscuta planiflora and Cuscuta epithymum are similar parasitic weeds and should be reported to the Department of Agriculture and Food when found.
Dodder Laurels (Cassytha species) are also parasitic twining vines but are native plants and usually grow on native hosts. They usually have at least some green on their stems, are rarely as golden as Golden Dodder, have 3 petals rather than 5 lobed flowers, have 6 or 9 stamens and tend to be perennial.
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).
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.