A breakthrough has been made in the battle against the box tree moth caterpillar.
First reported in the UK in 2008, the box tree moth (Cydalima perspectalis) has green-yellow larvae which are able to leave a box hedge entirely leafless and then attack the wood, which causes the plant to die.
Native to Asia, the moth has caused problems in gardens primarily in the south east of England, although recently it has been seen in Edinburgh.
In China, the box tree moth caterpillar is controlled by a parasitic wasp, and previously it was thought that the moth had no native predators in this country, but the National Trust has spotted that in Ham House and Garden in Richmond, jackdaws have been feasting on the insects.
Jackdaw eating a box moth caterpillar at Ham House © National Trust/Chris Davies
Following damage to Ham House’s kitchen garden, around 10 jackdaws have been patrolling the hedges which have been partially rejuvenated. Gardeners at the Ham estate are now looking at ways of attracting jackdaws and other birds, including changing the way they prune the hedges.
Rosie Fyles, head gardener at Ham House said: “We’ve noticed the jackdaws are most effective on the hedges which have been partially stripped of leaves by the caterpillars and so contain bigger holes – which makes the insects easier to spot.
“We’re now looking at ways to prune the hedges in a more open style, that allows increased air flow and gives the birds easier access to the caterpillars.”