Revealed: The top ten British garden pests of 2009

THEY are creatures that have the potential to leave gardeners shrieking in horror.

• Top 10: 1 Slugs and snails 2 Harlequin ladybird 3 Lily beetle 4 Vine weevil 5 Chafer grubs 6 Viburnum beetle 7 Pear leaf blister mite 8= Ants 8= Rabbits 10 Capsid bugs

The Royal Horticultural Society has revealed the top ten British garden pests of 2009.

The list contains familiar nasties such as slugs and vine weevils, as well as relative newcomers such as harlequin ladybirds.

The indefatigable enemies of all keen gardeners – slugs and snails – topped the list. Gardeners have long been at war with the slimy creatures, hated for their skill at chewing holes in leafy plants and vegetables.

Second on the list was a relative newcomer to British gardens: the harlequin ladybird.

This invasive species, originally from south-east Asia, has earned a bad name since it arrived in the UK in 2004, because it competes with native species of the bug.

And it has a habit of hibernating inside homes in the autumn. The ladybirds often clump together in large numbers, particularly in curtains.

Despite these traits, the harlequin ladybird is actually quite good for gardens, according to experts at the Royal Horticultural Society.

Andrew Halstead, RHS principal entomologist, said: "Adult harlequin ladybirds and their larvae feed mainly on greenfly and other aphids, so are helpful to gardeners.

"They will eat other insects if aphids are in short supply, but it remains to be seen whether the arrival and spread of this new ladybird will have an undesirable impact on other aphid predators."

At number three was the lily beetle, which enjoys munching through precious lilies. It replaced the cushion scale, a bug that feeds on woody plants, which was number three on the list for 2008 but did not feature last year.

Vine weevils came fourth, followed by chafer grubs, a newcomer on the list.

Mr Halstead said: "Chafer grubs can be a severe problem for lawns, especially on sandy or chalky soils. The beetle grubs sever the grass roots, allowing foxes, badgers and crows to rip up the loosened turf in the autumn and winter.

"These animals eat chafer grubs and so provide some control, but the lawn can end up looking like a badly ploughed field''.

The viburnum beetle came sixth. The larvae of these bugs have the ability to reduce leaves to lacework.

Seventh was the pear leaf blister mite, a microscopic pest that lives inside the foliage of pear trees, causing reddish pink or pale green blisters. By midsummer the affected parts of the leaves have turned blackish brown, giving heavily infested trees a very unhealthy appearance.

Ants and rabbits shared eighth place. Rabbits eat the foliage of many low-growing ornamental plants and vegetables. They also damage the bark of trees and shrubs, sometimes fatally, especially in hard winter weather when other plants are frosted or snow-covered.

The RHS also monitored the plants that caused the greatest number of pest inquiries.

Lawns came top, mainly due to the impact of chafer grubs, moles, leatherjackets, ant nests and worm casts.

Also on the list were apples, pears, viburnum and lilies.