Insects and fungus a remedy to the surge of knotweed in Britain?

Parasite insects that attack knotweed and yet remain neutral to native plant life have been released under close scrutiny of environmental experts at multiple undisclosed locations across the UK.

Fallopia japonica, commonly known as Japanese knotweed, is an alien plant that was initially introduced to Britain as a garden ornamental sometime in the 1800s. Its clusters of white flowers and large foliage were considered by the Victorians as an attractive addition to home gardens across the nation.

For years the spread of knotweed was neglected, causing the plant to uncontrollably widespread into the wild. Nowadays, the non-native species poses a severe threat to ecological balance in England, preventing native vegetation from thriving. Owning to the destructive nature of its bamboo-like stems, knotweed has the ability to prey on existing weaknesses in hard structures such as concrete and tarmac, causing massive problems to home sellers and property owners.

Japanese knotweed has so far remained unrivalled, with no natural enemies found in our ecosystem. However, on areas where knotweed originates from (China, Taiwan and Japan), there are dozens of scroungers that feed on it.

Since 2010, efforts are being made to finally limit knotweed spread on British soil. Environmental experts at CABI – a non-profit that specialises in innovative horticultural research – have claimed that the attempts to introduce knotweed’s natural predators onto our habitat had been a success.

Psyllid is a very small insect species that feeds off the sap found in knotweed stems and leaves. Several experiments across Britain saw the tiny insect released into the wild in controlled environment. These were to verify not only its effectiveness, but also make sure the pest is not harmful to any of native fauna and flora.

CABI is also said to have filled for a patent for a unique spray that contains fungus, which is able to cause mutilation to knotweed leaves and stems, while causing no damage to native vegetation. The bugs are not to eradicate knotweed plants completely, but are quite successful with weakening the plant. This makes knotweed susceptible to further damage – by e.g. herbicide treatment.

Could the insects and fungus treatment altogether put the knotweed surge to an end?

The research is still underway, with couple of more years before we have a concrete proof that bugs and fungus can be combined for a successful and permanent removal of knotweed in order to limit the contamination long-term.


Contact our office at 0800 122 3310 to receive further details on knotweed control methods and request a bespoke quote on your knotweed treatment plan. 


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