The mole (Talpa europaea) is a common British mammal and although rarely seen, due to its subterranean existence, its presence is well marked by the appearance of ‘molehills’ above ground, produced as a result of its underground tunnelling activity. Molehills and tunnels can be a real nuisance in gardens, golf courses, race-courses and other amenity areas.

Moles are territorial creatures, living alone in an extensive network of tunnels covering anything up to 4 acres, in soils suitable for tunnelling. Almost blind but with a good sense of smell, moles feed predominantly on earthworms, which fall into their tunnel systems acting as a pitfall trap. Moles patrol their labyrinth of tunnels on a four hourly cycle. Several young are born every spring but within five to six weeks they move out, over-ground, to establish their own territories.

Numbers are increasing

During the Foot and Mouth epidemic in 2001, mole numbers increased significantly because contractors couldn’t get on the land to control them, the following year strychnine was in short supply.  The only real natural predators of the mole are weasels however; it would appear that fewer weasels are around as less are being inadvertently trapped. Mole numbers therefore are much higher than before the foot and mouth epidemic and still rising. This will increase due to the loss of strychnine as a legal control method.

Controlling the mole

There are predominantly three main methods of controlling moles and each method has its advantages and disadvantages: -

·        Poisoning (Strychnine) *see above  

·        Gassing    (Aluminium Phosphide)

·        Trapping   (Scissor or Duffus)

Poisoning

Strychnine was subject to the Poisons Rules 1982 and the Poisons Act 1972. Only trained and certificated operatives could apply for a permit to use strychnine for mole control. This use was strictly controlled and only permitted on agricultural, horticultural and other extensive grassland areas subject to specific authorisation being granted. Strychnine as previously stated has now been withdrawn from use. 

Gassing

As an alternative chemical control method, aluminium phosphide is all that is currently available. This (aluminium phosphide) comes formulated as a pellet, which reacts with moisture in the soil and gives off phosphine gas; two products are available on the market at present Phostex and Talunex.

The supplier’s of both these aluminium phosphide products have spent a lot of money and generated a considerable amount of data to ensure continued registration of these products in the market place. Aluminium phosphide is being supported under the EU Directive 91/414/EEC as a plant protection product, as well as under the Biocides Products Directive 98/8/EC. This is now currently the only real chemical alternative to strychnine.

Aluminium phosphide is a Schedule 1 poison and operators must be trained and certificated to be able to purchase and use it for the control of moles and the manufacturer’s recommended guidelines must be followed.

Gassing is a very good method of controlling moles, but you do have to bear in mind where it is being used as it is not ideal for every situation, for example you cannot use it within 10 feet of habituated buildings. It is most effective in clay or heavy soil as when used  in sandy soil the gas is not retained long enough to ensure its effectiveness.

Some view gassing a more expensive control method in comparison to Strychnine but the reduced risks outweigh the cost. Phosphine gas under normal conditions will have been liberated from the pellet in up to 48 hours and moles will generally have travelled throughout their tunnel network within that time ensuring effective control.

Trapping

Although trapping is regarded by some as old-fashioned, it is also often regarded as being the ‘cheapest’ form of control. However although the traps themselves are relatively cheap, typically £6.00 - £8.00 using them is labour intensive. More costly site visits are required and there are frequent losses either from people pulling them up or by them getting dragged down by the mole or damaged by machinery. There is no legal requirement under the existing legislation to inspect traps set for moles at any specific interval, however, “humanness and efficacy considerations should be taken into account and any traps used should kill the mole humanely".