Watch out for parasitic weed

Home gardeners are asked to be on the lookout for a thread-like, parasitic weed after it was discovered in a backyard vegetable patch in the Wheatbelt.

Department of Agriculture and Food (DAFWA) Invasive Species Manager Jon Dodd said golden dodder (Cuscuta campestris) was a leafless parasitic plant. It grows as distinct ‘yellowish threads’ that twist around its host, sometimes causing significant yield and quality reductions on its host plant.

“There are more than 90 known hosts of golden dodder, most of which are annuals and include a wide range of ornamental, vegetable, herb and crop plants,” Dr Dodd said.

“It is most likely to be found in medium to high rainfall areas and under irrigation, posing a risk to some horticultural crops and broadleaf crops such as lupins and canola.”

Dr Dodd said the declared plant was reported by a DAFWA officer, who recognised the threadlike weed growing in a backyard vegetable patch in Wongan Hills and on seedlings, and sent in samples to confirm identification. The dodder was growing on several different hosts including tomato, capsicum and basil.

“DAFWA is investigating possible sources of this weed and has alerted major retail outlets and wholesalers of vegetable and herb seedlings about the detection,” Dr Dodd said.

“To date, we have had no further reports of the weed, but we are asking anyone who sees this unusual weed growing on vegetable and herb plants in their garden to contact the department’s Pest and Disease Information Service (PaDIS).”

Golden dodder has small creamy white flowers and smooth, delicate thread-like stems about 1mm thick. The stems are usually bright yellow in colour, but may occasionally be green or pink.

“The stems twine round the host and attach to it by sucker-like pegs,” Dr Dodd said. “Parts of the stem may be attached with other parts hanging free.”

Golden dodder is widespread in eastern Australia. Within WA, populations of golden dodder are established along parts of the Warren River near Pemberton and around Albany.

The weed is not to be confused with the unrelated native dodder (Cassytha species), which is found on native shrub and tree hosts, and has tough dull green stems.

Suspect sightings can be reported to PaDIS on freecall 1800 084 881.

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Photo captions: Department of Agriculture and Food Invasive Species Manager Jon Dodd holds up punnets of basil and tomato seedlings infested with golden dodder.

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File photo: Golden dodder is identifiable by creamy white flowers and thread-like stems which are usually bright yellow in colour. Pictured here on host plant vinca, a common garden plant.

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File photo: Golden dodder is identifiable by creamy white flowers and thread-like stems which are usually bright yellow in colour. 

Media contacts: Jodie Thomson/Lisa Bertram, media liaison   +61 (0)8 9368 3937