Weeds

Wild Radish (Raphanus raphanistrum)

Family: Brassicaceae
Form: Herb
Origin: Native to Mediterranean region
Flowers/Seedhead: In branched racemes. Flowers from late winter to summer.

Wild Radish is becoming one of the most difficult weeds to control in our area, with land further North showing signs of resistance to chemical control of the plant. Wild Radish is in the Brassicaceae (mustard) family and there are many related family members including wild turnip, shepherds purse, turnip weed to name a few.

Wild Radish is a schedule 4 – Class 4 Noxious weed. It can cause significant crop yield losses as it establishes quickly, is vigorous and is a fast growing plant. Wild radish that emerges with the crop can cause more than 90% yield loss whereas populations that emerge more than 7 weeks later cause less than 20% yield loss (Blackshaw 2001).

The plant is easily spread by animals, wind and water but mostly through agricultural products containing the weed.

Control of wild radish has been through the use of Herbicides as the most fast and effective way to control plant populations. However this has led to herbicide resistance in the plants due to their overuse. Control of the plants now depends on a combined integrated weed management approach incorporating a range of chemical, cultural and biological weed control techniques and a proactive approach to weed management.

For further information:
Wild Radish Information on the plant, control and effect on annual crops - click here
Weed Identification of Wild Radish - click here
Maximising chemical control of resistant wild radish, Landmark - click here
Breaking the Wild Radish bank, GRDC - click here

Photos courtesy of Department of Agriculture and Food WA, CSIRO and flickr.com


 

 

Bridal Creeper (Asparagus asparagoides)

History
Bridal Creeper was originally imported from South Africa and spread quickly throughout the southern regions of Australia as a tough and hardy plant, greening up the autumn garden. As the common name suggests, its pretty white flowers and heart shaped leaves were also often used for bridal bouquets, garlands and decorating.

Impact
Regarded as one of the worst weeds in Australia, Bridal Creeper has the ability to have an imense impact on the economic and environmental stability of our area if not properly controlled. Its climbing stems, and underground tubers give it the ability to choke out our native flora, rapidly reducing the natural habitat of our local fauna. Bridal creeper thrives right throughout the agricultural regions due to high soil nutrient levels. And the plants tolerance to frost and dry conditions makes it extremely difficult to control once established.

Distribution
Two dispersal methods give Bridal Creeper the ability to spread quickly and effectively, with an excellent chance of survival. Bridal Creeper is dispersed in the environment by the following means;

  • Berries - One bridal creeper can produce more than 1000 berries per square metre. Birds, rabbits and foxes feed on the berries and later excrete the seeds allowing them to be spread over vast distances.
  • Tubers - The root system is made up of tubers\rhizomes, meaning removal of the plant is not effective unless all the tubers\rhizomes are removed. This ensures the spread of the plant via roadside grading or removal without proper disposal extremely common.

Treatment
The most effective treatment for Bridal Creeper removal is to use herbicide spraying. However in areas with native flora this is not always the best method. Introducing biological controls such as Bridal Creeper Rust Fungus, Bridal Creeper Leaf Hopper and Bridal Creeper Beetle, help to slow the growth of the plant on the surface of the soil thereby reducing the production of berries and slowing the production of tubers under the soil.

This is however a slow process that takes several years to achieve results. Physical removal can be effective for extremely small areas but as you must ensure every single rhizome is removed, this can prove extremely difficult. In addition plants and tubers that have been physically removed should not be mulched or composted, but wrapped in plastic bags and placed in your kerbside rubbish bin or through your local tip.

Fire can also be effective in large infestations but requires permission from your local government authority to do so.