Slugs and snails were the number one problem on the 2009 Top 10 garden pests list, according to the Royal Horticultural Society (RHS).

The RHS Entomology team, based at RHS Garden Wisley, have compiled their annual list of garden pests, based on the enquiries by RHS members during the last year.

In second place were harlequin ladybirds; third place went to the infamous scarlet lily beetle; with vine weevil and chafer grub in fourth and fifth place respectively.

                                          
Harlequin Ladybirds                                                                                  Scarlet lily beetle

The cool, wet conditions of the 2009 summer were ideal for snails and slugs.

The non-native harlequin ladybird produced the second largest number of enquiries, although it is not a pest in the conventional sense.  Since its arrival in 2004, it has caused a nuisance by coming into houses to hibernate in the autumn.  It has also been given a bad reputation as a destroyer of native ladybirds and other aphid predators. 

RHS Principal Entomologist, Andrew Halstead, says ‘’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’’.

The plants that produced the greatest number of pest enquiries:

1 Lawns
2 Apples
3 Viburnum
4 Lilies
5 Pears

 

Lawns are usually the number one trouble spot in a garden.  The main problems are chafer grubs, moles, leatherjackets, ant nests and worm casts. 

Andrew Halstead says ‘’ 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 top 10 pests of 2009

 2009        

1 Slugs/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     

9 Rosemary beetle

10 Capsid bugs  

 

 

The RHS offers a unique advice service to all its members. Gardeners can write, email or phone the Advisory service, or visit one of the four RHS gardens (Wisley, Hyde Hall, Rosemoor, Harlow Carr), to discover the answer to any horticultural question that is plaguing them. In the case of a pest, the Entomology department can offer gardeners a solution to their problem and advise them on the necessary action.

The RHS Entomology team are asking people to take part in an on-line survey of scarlet lily beetle, berberis sawfly, hemerocallis gall midge  and rosemary beetle.
For more details go to: http://www.rhs.org.uk/Science/Plant-pests