The risk of rodent infestations in feed stores and general farm buildings is increasing, which is not surprising given the change in weather and scarcity of natural food supplies.

Rodent infestations can quickly multiply if left unchecked.

For example, a female rat can produce five to six litters per year with a gestation period of just 21 days.

Litter sizes are commonly between five and 10 rats and as high as 12 to 14, while newborn rats can reach sexual maturity anywhere from five to eight weeks of age.

Rats can pose a serious risk for human health (Weil’s disease) or cause significant damage to equipment, wiring, etc.

The campaign aims to promote the responsible use of chemical rodent controls and best-practice techniques to do so

A taskforce made up of Government departments and agencies, non-governmental organisations and product manufacturers are working together in a campaign for responsible rodenticide use (CRRU).

The campaign aims to promote the responsible use of chemical rodent controls and best-practice techniques to do so, while also minimising any risk of exposure to non-target species such as birds, other predators and farmyard dogs or pets.

A wildlife awareness training course was established in recent years by CRRU in co-operation with the Irish Agricultural Supply Industry Standards (IASIS).

The course was targeted at professional pest control technicians and other competent users of rodenticides.

A list of accredited professionals is available on www.iasis.ie.

CRRU code

A seven-point CRRU code was also established to provide concise recommendations. The seven points are as follows:

  • Always have a planned approach.
  • Always record quantity of bait used and where it is placed.
  • Always use enough baiting points.
  • Always collect and dispose of rodent bodies.
  • Never leave bait exposed to non-target animals and birds.
  • Never fail to inspect bait regularly.
  • Never leave bait down at the end of the treatment.

    • The code advises to carry out an assessment of the site to see where rodents are entering the yard or buildings and, in particular, to ask where they are seeking out cover. This should not be altered before the infestation is addressed as it will make treatment more difficult. Remedial action such as removing or trimming back weeds’ shrubs, bushes, etc, that provide cover or rodent proofing entry points to feed stores and sheds should be undertaken following treatment.

    The code advises that any bait should have achieved control within 35 days

    Rodenticides should be placed alongside areas where rodents travel or congregate and should ideally only be used as long as it is necessary to achieve satisfactory control.

    Removing access to other food sources, such as spilled grain, will help to encourage higher consumption of bait. The code advises that any bait should have achieved control within 35 days and that where satisfactory control is not achieved, a more potent anticoagulant should be considered. If intake is low relative to the size of the infestation, re-siting of bait points or the type of bait box used should also be considered.

    Rodent removal

    The bodies of dead rodents can carry residues of rodenticides and if eaten by scavengers, predators or pets may lead to chemical exposure for wildlife. Rat bodies may be found for several days after rats have eaten bait and it is common for rats to die up to 100m or more away from baited sites.

    It is a requirement under the Bord Bia sustainable beef, lamb, dairy and other quality assurance schemes to record rodent/pest control strategies. The location of bait points should also be marked on a farmyard sketch.