REVEALED: Jumping, munching insect ‘taking on Japanese Knotweed’

Scientists at Cabi say ‘psyllids’ can weaken the plants’ ability to spread and turn it from a threat to just ‘another annoying weed’.

Japanese Knotweed can be seen invading a garden fence of a home in the UK, making its way towards a green house.

The fight against Japanese Knotweed has taken a leap forward after scientists at non-profit environmental organisation Cabi discovered a tiny insect that could eat away at the growing problem.

The Times reports that Aphalara itadori, a type of jumping insect from the psyllid family, is getting its teeth into the most aggressive type of Japanese knotweed in Britain.


Cabi, formerly Commonwealth Agricultural Bureaux International, says that in the UK it is estimated that a nationwide attempt to control the weed would cost over £1.56 billion with most methods of control relying on chemical and mechanical approaches.

Since 2000 its scientists have been researching the possibility of using natural control methods to curb the onslaught of Japanese knotweed in the UK.

Aphalara itadori on Japanese knotweed leaf.
Cabi: Aphalara itadori on Japanese knotweed leaf.

Psyllids were first released into the wild in Britain in 2011, when they became the first insect authorised for release as a biological control in Europe.

But British winters got the better of the little critters as the insects had lost their resilience after being bred for 150 generations in a lab while undergoing testing to make sure that they wouldn’t harm native plants.

To rectify the issue, botanists found a new psyllid from Japan from the north of the country.

UK trials began on this variant in 2019 and results show the bugs are successfully braving British winters and seriously damaging Bohemian knotweed – which is a bigger and more aggressive type of the plant which is more common in Europe.


Dr Dick Shaw, an entomologist and senior regional director for Cabi, told The Times: “I think there’s still the right psyllid out there in Japan that would hit it. We’re not giving up.

“One of the strategies is to collect the ones that have overwintered successfully and interbreed them. We’re only three years into the new release programme so we’re still hopeful.”

Japanese Knotweed was brought to Britain by the Victorians as an ornamental garden plant and to line railway tracks to stabilise the soil.

Read more about Japanese Knotweed HERE.

One Comment

  1. When will they stop harping on about Knotweed!, it’s a plant and ironically not that easy to grow and hates dryness. Bamboo and Wysteria is worse for your house and nobody cares. It only heads through cracks and if you have cracks in your house, you have bigger issues. Wysteria does more damage to your soffits and facias just like ivy.

    As for these bugs, when they have eaten all the knotweed, then what? turn into another annoying species that eat corn or something? least it keeps the likes of Dr Dick employed IG.

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