Ermine moth larvae infest Bradford park
19 May 2011 Last updated at 11:39 BST
An urban park in Bradford has been infested with thousands of caterpillars, stripping 15 trees of all their leaves.
They have been identified as Ermine moth larvae and have formed large communal webs covering railings and tree trunks.
As Phil Bodmer reports, the infestation has been caused by the recent warm weather.