Repellents to control unwanted bats
The following suggestions can be used to keep bats away before they become pests.
- Naphthalene (moth flakes) has been used as a repellent with some success but the quantities needed are such that the odor can be hazardous to humans' health. This solution is only temporary as the bats will return once the odor is gone if their entry points have not been sealed.
- Bright lights placed in attics may disturb bats enough for them to leave. On the other hand, it may also cause them to move to more concealed areas behind boards or between walls. The amount of light necessary to disturb the bats may create an electrical hazard. Fans have been used to create air drafts to disturb bats but again with very limited success. However, once bats have been physically excluded, permanently venting an area or adding a window may make a structure less attractive to bats in the future if new entry points develop.
- Ultrasonic devices are not effective in repelling bats. Be very wary of any pest control company that suggests the use of ultrasonic devices or toxic chemicals.
There are no chemicals registered in Minnesota for use on bats. At one time DDT and Rozol were used to poison bats. However, these chemicals could seep into humans living quarters posing a significant health hazard to people. Use of these chemicals also greatly increased the risk of humans and pets coming into contact with sick or dying bats. Their use has been discontinued and is now illegal.
The reason most methods of bat control fail is because they do not prevent bats from reentering the structure. Whether tackling the problem yourself, or hiring a pest control operator or carpenter, the goal should be the same - non-lethal, non-chemical, permanent, physical exclusion of the bats.