Toxic caterpillar invasion spiralling out of control
Conservationists are battling a ‘phenomenal’ invasion of toxic caterpillars and they have warned that their numbers are spiralling out of control. Millions of pounds have been invested into attempts to prevent the spread of Oak Processionary Moths (OPM) since they arrived in London in 2006. The caterpillars can cause asthma attacks, skin rashes and sickness in humans, while their larvae strip oaks of their bark and feed on the leaves, leaving the trees vulnerable to disease.
The City of London manages 9 parks in the capital and have spent £100, 000 on eradicating the unwanted pests, this figure is up 10 times on the previous year. In 2015, inspectors found just 15 OPM nests in Hampstead Heath, Highgate Wood and Queen’s Park. Last year the number soared to more than 2,000.
The destructive insects were accidentally introduced into the UK when oak trees from Southern Europe were imported for a development site in London in 2006. They have spread to all 33 London boroughs and cost the government £37 million in pest control bills.
It is imperative for landowners to remove the nests or use insecticidal sprays soon after the caterpillars hatch. However, neither approach is 100% effective. Colin Buttery, director of open spaces at the City Corporation, said: “We are now reaching a ‘tipping point’ at some properties, such as Hampstead Heath, where nest numbers have grown exponentially in 2018. Colin warned that it is expected its other parks to experience a similar boom caterpillar numbers in the coming years. A spokesman said officers were working with the Forestry Commission and specialists carrying out targeted treatment to control the caterpillars. John Beyer from the Heath and Hampstead Society told the Standard: “When they first arrived we thought we could control the mess and the numbers would be controlled. But that doesn’t seem to be possible. My personal feeling is that sooner or later we will have to go to a system where we treat the trees where there are paths so the public is protected and then you will have to ignore the other trees because the numbers are getting so great. It didn’t seem a big issue but now it’s really worrying. It’s phenomenal — we can’t take it in.”