By Adam Barnett
People are being warned to watch out for toxic caterpillars which can cause asthma attacks, skin rashes and vomiting.
The Forestry Commission has warned of an outbreak of oak processional moths (OPM) in their larval stage in south-east England and Greater London.
As caterpillars, the insects have 62,000 hairs which they can eject from their bodies, causing fevers and irritation to both the eyes and throat in humans they touch.
62,000 ejecting hairs
Ashtma attacksSkin rashesIrritation to eyesVomitingIrritation to the throat
A spokesperson for the Forestry Commission said they were currently working on treating the outbreak, but were racing against the clock.
"The treatment programme is expected to continue until late May or early June," they explained. "After that, the caterpillars will be too large to be affected by our preferred treatment product."
People are being advised not to touch the caterpillars, whose hairs are long and white and remain active after being ejected.
So far they have been spotted in large numbers in Greater London, including in Kingston upon Thames and Brent, as well as Bracknell Forest, Slough and Guildford.
Some people have already been affected by the caterpillars, which emerged in mid-April.
Do not touch
One gardener quoted by the BBC said she was exposed to a tree infested with OPM caterpillars and became "violently sick".
"My first symptom was a rash on my tummy", she said. "During this time I had spells of feeling violently sick.
"The rash got worse and the left side of my face became covered in this sore irritating rash. My left eye became very sore and weepy."
She added: "I contacted my doctor and it was confirmed I had been severely affected by OPM and must keep away from the source as over time I had developed a severe allergic reaction."
This article originally appeared on our sister site, iNews