Verbesina encelioides, commonly known as crown beard, has become a serious environmental weed in south-west Australia including the Geraldton Sandplain.
It has the ability to invade native vegetation and displace native flora. It has high seed production, seed dormancy, ability to tolerate dry conditions and allelopathic effects, meaning it impacts on other plants growing around it.
It is of particular concern on off-shore Islands where it can cause substantial degradation to seabird habitat by creating a physical barrier to nesting birds, lowering nest density and shading out native plants.
There are also several reports pointing to its toxicity in sheep.
Dr Bob Nickels, private consultant with Combined Rural Traders (CRT) said “Crown beard contains galegine, a substance that causes a pneumonia type problem in sheep through the build-up of excessive fluid in the chest cavity which can cause death.”
On post mortem, the thorax will be full of fluid with as much as 2-3 litres of straw coloured fluid with fibrin tags and congestion and oedema of the lungs.”
There is no treatment available for sheep so prevention is imperative. It can be prevented by getting rid of as much crown beard as possible from the paddocks and fence lines and by providing hay or some other good quality feed to the sheep,” said Dr Nickles.
The Department of Parks and Wildlife’s management notes indicate that, “crown beard can be controlled mechanically by hand removal of isolated plants, including tap root, before seed set.”
For more information on crown beard best weed management options, please contact the Department of Parks and Wildlife.