A Fungus to Replace herbicide for Black wattle

Have you ever heard of a fungus that helps control invasive alien plants? Meet Cylindrobasidium torrendii, a naturally occurring fungus that could revolutionise black wattle treatment. This tiny organism is helping manage areas of invasive species like Acacia mearnsii (black wattle). Black wattle is a fast-growing, aggressive plant that spreads rapidly and outcompetes indigenous vegetation. Black wattle disrupts ecosystems by consuming excess water and nutrients, displacing the indigenous flora.
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Recently, the Grootvadersbosch Conservancy had the privilege of hosting Dr Alan Wood from the Agricultural Research Council, an expert in plant pathogen behaviour and biocontrol development. Dr Wood presented his biocontrol solution as an alternative to herbicide to control black wattle on cut stumps. The Conservancy is working with Dr Wood to test this approach in real world conditions.  

Dr Alan Wood visiting one of our sites to test Cylindrobasidium torrendii in real life conditions

During his visit, Dr Wood demonstrated to the Grootvadersbosch team and a group of alien clearing workers how the biocontrol works. He explained how to mix and apply the fungus on stumps immediately after cutting down black wattle trees, ensuring it is absorbed through the stump and into the roots. This method targets the tree’s internal systems without the potential environmental and human health risks associated with herbicides.
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Unlike herbicides that can harm the environment and workers who appply, without the correct protective equipment, Cylindrobasidium torrendii offers a natural, water-based solution. The biocontrol is applied directly onto the stump after cutting the tree at ankle height with either a chainsaw or silky saw. From there, the fungus colonises the tree’s roots and slowly decomposes them, preventing regrowth. It’s like pressing a natural shutdown button for unwanted black wattle trees. Best of all, the fungus is species-specific, meaning it won’t spread to surrounding indigenous plants, making it an eco-friendly alternative to herbicides. Dr Wood is trialing a new, and more cost effective, formulation of this fungus. 

An alternative treatment to herbicide for Black wattle

Protective equipment worn by workers using herbicide.

Although Cylindrobasidium torrendii isn’t a fast-acting solution, it is possibly a more sustainable and less harmful method for combating black wattle. It takes time for the fungus to spread and for the decomposition process to fully take effect, but the long-term benefits could make it worthwhile and this approach allows indigenous plants to recover naturally. 

Cylindrobasidium torrendii could be a good alternative to herbicide, especially close to rivers where cornerns for the impact on biota are often the greatest