TDA 115 Grey squirrel control -2007
Tree Damage Alert No 115
12th April 2007
Grey squirrel control by poisoning – 2007 Changes
In Arboricultural Practice Note 7 Grey Squirrels in Parks, Urban Woodlands and Amenity Plantings we highlighted the extensive and disfiguring bark-stripping damage Grey squirrels (Sciurus carolinensis) can cause to trees. Such damage, which is often visible in roadside trees from a moving vehicle, continues to be a concern for tree owners and managers. There is need to maintain control measures if young trees are to have a chance of reaching maturity. APN 7 provides advice and recommendations on the management of Grey squirrels and the protection of trees from the damage they cause. This includes how to control Grey squirrel numbers using warfarin poison. There are some changes in the use of warfarin that come into effect this year.
The most important change is the withdrawal of approval for use of the Grey Squirrel Liquid Concentrate MAFF approval no. 06455. This prevents users from mixing their own bait. There is however one minor concession – any prospective user, who has Grey Squirrel Liquid Concentrate in store, may continue to use it, but again there are conditions. The Liquid Concentrate must have been purchased before 31st December 2006 and it must be used by 31st December 2007, but in practice, for tree managers, the cut off date is 15th August 2007. This is because the label instructions state that 0.02% warfarin bait may only be used for ‘tree protection’, between March 15th and August 15th.
From now on only 0.02% warfarin ready mixed on whole grain wheat bait – Grey Squirrel Bait MAPP no. 13020 - is available and only from Killgerm Chemicals Ltd., at Denholme Drive, Ossett, West Yorkshire, WF5 9NB at a current cost of £22.80 for 10kg. On-line orders may be placed at http://www.killgerm.com. Apart from the mixing instructions all the other on-label conditions for use remain in place. These include a requirement to search the control area, pick up all squirrel cadavers found and ensure their safe disposal through an appropriately registered waste disposal contractor. Any bait that has been soiled by moisture and is not in a suitable condition to be returned to the hopper must be removed for safe disposal either by burning or through a registered waste disposal contractor.
Other precautions that must be taken include wearing synthetic rubber or PVC gloves (European Standard EN 374) when handling the ready mixed bait. Gloves may be either unlined or flock lined. Disposal, after use, of contaminated gloves and any other protective clothing or equipment must be through a registered waste contractor.
And finally don’t forget the dreaded Risk Assessment. A written one should cover each and every Grey squirrel control operation. Control of Grey squirrels is essential if we are serious about managing healthy trees into maturity and beyond!
Harry Pepper, AAIS, Alice Holt Lodge, Wrecclesham, Farnham GU10 4LH
This is one in an occasional series of Tree Damage Alerts produced for the benefit of the arboricultural profession and issued by the Arboricultural Advisory and Information Service.
AAIS Alice Holt Lodge Wrecclesham Farnham Surrey GU10 4LH
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