How to use rodenticides safely

Campaign for Responsible Rodenticide Use

Using rodenticides safely

The control of any pest is best achieved with an Integrated Pest Management (IPM) plan that utilises a range of strategies to achieve the best possible level of control. IPM strategies include:

  • Physical control (e.g. removing habitats from pests to live and breed)
  • Cultural control (e.g. changing lambing areas to a field that offers less cover for foxes)
  • Biological control (e.g. the managed introduction of organisms to reduce pest numbers)
  • Genetic control (e.g. resistant varieties not commonly used in the UK)
  • Quarantine (e.g. fencing off areas to block or 'quarantine' the area from pests)
  • Chemical control (e.g. using poison baits to control a range of pests and the most frequently used method in the UK).

Rat and mouse infestations need to be adequately controlled to reduce the risk from disease and of damage. The primary aim should be to avoid infestation. Once established, rats and mice can be difficult to control.

Consideration must be given to all available controls – not just the use of rodenticides - including clearing away rubbish, proofing of buildings, and the use of traps. Regular monitoring of high-risk areas is advisable.

Assuming that an IPM plan is implemented using a range of the strategies listed above, it is reasonable that chemical control may play a part in the program. Chemicals used for vermin control are formulated in a number of ways. For example, aluminium phosphide tablets used in rabbit control such as Phostoxin, require a high level of expertise and diligence in their use, as fumigant gases can have significant and acute adverse effects on the user when things go wrong. They can be sold only to professional customers and are governed by the Poisons Act.

Bait formulations are often used as part of an IPM, because it is not always easy or possible to identify a den, nest or warren. The pest may also be transient in an area, as in the case of foxes, and in the case of mice infestations there may simply be too many holes in an area to treat each one individually.

Registered baits are formulated to deter or limit their attractiveness to non-target animals. This is achieved through a range of strategies such as:

  • formulating the bait using a chemical that is more selective to the pest than to non-target animals
  • the addition of bittering agents to limit bait intake by non-target animals
  • colouring the bait to make it unattractive to non-target animals
  • using only a certain amount of bait
  • leaving the husk on grain bait, or removing it depending on the nature of the target animal
  • burying the bait to make it unavailable to non-target animals
  • covering the bait after a certain period of time to limit access by non-target animals.
  • using bait stations preferably purpose built to keep baits away from non target species.
Rats are shy animals and nervous of strange objects therefore, it is better to use existing materials rather than introduce bait containers as long as the bait can be adequately protected.
Rats are shy animals and nervous of strange objects therefore, it is better to use existing materials rather than introduce bait containers as long as the bait can be adequately protected.

What to do before treatment

Rats are shy animals and nervous of strange objects therefore, it is better to use existing materials rather than introduce bait containers as long as the bait can be adequately protected. Reducing the availability of food at the start of treatment, or shortly afterwards, can encourage rodents to feed on the bait you have placed for them.

Site survey

A survey should be conducted to establish the type, level and extent of infestation. This will help to identify important elements such as the presence of children and non target animals. It will also identify influencing factors such as the need to improve housekeeping, reducing the availability of alternative foodstuffs and highlight building / drain repairs.

Bait formulation

The formulation should be suitable for the conditions and circumstances of the infestation. Resistance to certain ingredients in baits should be investigated and the choice of product made taking resistance into account. A wide range of products are available including:

  • Meals
  • Cut or whole grain
  • Pellets
  • Wax blocks
  • Edible lards / gels
  • Liquid baits
  • Contact dusts

And remember only use a product that has been approved for use as a rodenticide. Read the label and ensure that you comply with the statutory conditions for use and follow the product directions.

Recording

Make a written record of where you have placed the bait, what was used and how much has been laid. Inform those with regular access to the site that rodenticide has been put down.

Monitoring

Monitor the treatment regularly so you can:

  • Ensure that sufficient bait is available.
  • Check the baiting points remain secure.
  • Deal with spillages or other problems as they occur.
  • Observe the progress of the control.

Hoarding of bait

Remember that rats may remove baits which can be carried and hoard them, or drop them where children or non target animals can gain access to them, so secure any sachets or wax blocks at the placement site. If more bait is being consumed than expected for the size of the infestation, consider whether hoarding is a problem.

Removal of dead rodents

Dead rodents should be disposed of safely by following the label advice or by using a disposal contractor. This will reduce the risk of secondary poisoning of other species. After treatment it is your duty to ensure that all remains of bait and containers are removed from the site and disposed of according to the label instructions.

Placing the bait

Rats are likely to be found in:

  • Farm buildings
  • Burrows
  • Piles of rubbish and vegetation

If you cannot find suitable cover to protect baits, indoor baiting or using bait boxes may be the answer. Home made boxes will also be suffice.

Replenishing bait

Inspections of the bait should be made every 1-2 weeks and replenished as necessary.

Long term baiting

Here it is essential that baits are adequately protected from other species and moisture. Whole grain, pellets and wax blocks are most suitable here.

Storage of bait

Keep all rodenticides secure in a suitably located store. Bait should be kept in the original package.

Rodent borne diseases

Rodents can carry serious and life threatening diseases. These can be caught by contact with surfaces or water contaminated with rodent urine. Waterproof gloves should be worn in infested areas. Cuts and abrasions should be covered and exposed skin washed before eating, drinking and smoking.