Red witchweed (Striga asiatica) is a parasitic plant that grows attached to the roots of certain commercially important grasses and summer cereals, including sorghum, corn (maize), rice and sugarcane.
Red witchweed is exotic to Australia but was found on a property near Mackay in Queensland in 2013. The weed remains contained within the Mackay region, with approximately 87 hectares known to be infested.
Government and industry action to eradicate red witchweed
Biosecurity Queensland, as the combat agency, has been working with industry to eradicate the weed since it was detected, however, the response has not been covered by existing national agreements which include mechanisms to share costs.
In July 2015 industry and government reached an agreement on a ten year (2015-16 to 2024-25) response plan, to eradicate Red witchweed from Mackay. The response plan was agreed to the value of $5.86 million and will be cost-shared on a 50:50 basis between governments (the Australian, state and territory governments) and industry groups (CANEGROWERS; Grain Producers Australia; Cattle Council of Australia and the live export industry and Canegrowers on behalf of the Australian Cane Industry).
Current scientific advice provided by the Consultative Committee on Exotic Plant Incursion (CCEPI) indicates that it is technically feasible and cost beneficial to eradicate red witchweed from the Mackay area.
Land affected by Red witchweed, approximately 87 hectares, will be intensively treated for three years to deplete the soil seed bank of this weed. This treatment period will be followed by a seven year period of infield management and surveillance to mop up any surviving seeds that may germinate.
An independent review of the first (treatment) phase will be completed by 30 June 2018. The review will look at the effectiveness of the response and ensure that it continues to be efficient and meet its objectives beyond 2018.
Other than the areas being directly treated, affected land owners will still be able to grow crops and operate their properties in accordance with the existing Queensland quarantine restrictions.
Eradication will not happen overnight. It will take at least decade until authorities can be sure that the eradication activities have worked. Success is also dependent on the cooperation and ongoing efforts by growers and graziers in the region as well as the affected community.
What you need to do
Good biosecurity measures are vital to stopping the spread of weed seeds and other plant pests and diseases.
Please watch Biosecurity Queensland’s red witchweed video to learn what it looks like, and some simple steps that can be taken to stop it spreading.
Importantly if you see red witchweed on your property or in public areas (such as on roadsides) report it to Biosecurity Queensland on 13 25 23 or through the Exotic Plant Pest Hotline on 1800 084 881.
Farmers and graziers
For producers who suspect they have red witchweed:
- Report the plant immediately to Biosecurity Queensland on 13 25 23.
- Take photos of the infestation and store them until you are contacted by Biosecurity Queensland.
- Do not attempt to remove any flowering plants, as this may allow the weed to spread tiny, dust-like seeds.
- Don't move off-site any soil, machinery or products (including mulch) that might contain soil. This will help avoid spread of seeds to other properties.
- Seeds are tiny and can easily drop into the soil, enabling its spread. Therefore, keep the weed in place until Biosecurity Queensland can investigate.