The control of pests such as wasps, clusterflies, hornets and rodents may unintentionally affect bats or their roosts, so care should be taken when controlling pests in an area where bats are or are known to have been, present.

To avoid an offence from being committed, if bats are known to be or have been present, or bats or their droppings are discovered at any stage (including after operations have started), work must not commence or must stop immediately and advice be taken from the Statutory Nature Conservation Organisation (SNCO).

In addition, be aware of this pest control best practice to protect bats:

Rodenticides in an open tray should never be placed below roosting bats

Spring, cage or sticky traps should never be used in bat roosts

Ultrasonic deterrents should not be used in a bat roost.

In some circumstances, eg where wasps are a health and safety issue, insecticides suitable for use in bat roosts can be used, but advice must be obtained from the appropriate expert about when to apply them, particularly if bats and wasps share a common access point or the nest is close to the area used by the bats. Usually a survey by a bat worker/roost visitor would be required to determine the case-specific advice.

The use of timber treatment chemicals in roofs to control for woodworm used to be responsible for the deaths of whole colonies of bats. Since the problem has been recognised, many products have become available that are more suitable for use in bat roosts to treat the timber and to treat infestations.