Extract from the magazine Villafamiljen No. 4/-98

A selection of electronic vermin control devices. The three devices piled at the back (retail price; $ 40-175) are not equipped with weather resistant speakers, thus only suitable for installation in dry and warm spaces. The round resonance model to the left (Topo Stop, $115) keeps the vermin away from walls and floors. The square shaped ultrasonic model just behind ($ 125) has a weather protected speaker and is suitable for installation in cold and damp places. The two units at the front to deter moles and voles by emitting resonance sound in the soil. The one to the extreme right ($115) has drainage slots for condense water and the electronic parts are completely epoxy moulded (water proof), something the unit in the middle ($34) lacks.

Photo: Dan Ljungsvik

In his struggle against vermin man has historically developed more and more sophisticated methods. The importance of the basic facts for successful pest control have however often been placed in the back seat. Here we offer you a brief reminder about the important factors for effective vermin control.

Seal the house
You can of course never completely seal off a house or garden against vermin. If you already have plugged all holes you can detect, netted the ventilation slots in the attic or you have dug protective nets around specially attractive flower beds, then you have a basic protection against rodents.

Remove anything eatable
The vermin is constantly looking for food. Make certain that anything eatable (Oh yes, soap and candles too!), especially in your holiday cottage will be kept in closed cans (glass or tin – not plastic!) and keep the area below the sink clean and tidy.

Be persistent
Finally you must be as persistent as the vermin. If you choose traditional methods for vermin control you are the one that needs to show perseverance in terms of constantly having to empty traps or refilling the bait stations with poison, both methods which are rather impossible in summer houses deserted for the winter.

However, if you put your trust in the new technique with electronic vermin chasers, life will of course become a lot more comfortable. But are the electronic devices effective?

On this the learned disagree. On one hand you have traditional pest control companies claiming the superiority of their services. On the other hand there are today many satisfied customers using electronic vermin control devices. Manufacturers of the equipment also indicate that there are a number of scientific studies all confirming the good experiences.

Claims that the hearing of people or pets can come to harm have sometimes been stated as an argument against mice chasers. Since ultrasonic waves by definition cannot penetrate even a thin paper this argument is for practical reasons not valid – vermin repellers are mostly installed in uninhabited spaces such as attics, ventilated cavities below the ground floor etc. Also, modern electronic mice chasers do not emit the sound waves continuously but in certain intervals and at random.

Below you´ll find a comparison between common vermin control methods with pros and cons listed. In each category you can find several different products to choose from. Text Rosi Tholin

Pros & cons
 Rat poison
 Electronic pest control

Easy to administer.
Low initial cost.
Practical when infestation is limited.
Low initial cost.
Easy to install and operate.
Automatic - ideal for closed summer houses.
Long term effect – microprocessor guided sound variation.
Money-Back-Guarantee 1)
Low long term investment 2)
Hygienic. Environmentally safe.

Dangerous for children and pets.
Often short term effect – vermin learns to avoid the poison.
Must be re-administered several times a year – impractical in closed summer houses.
Sanitary discomfort – smell of carcasses in the house.
Increased poison tolerance among vermin – reduced long term effect.
Environmentally hazardous – harmful for birds of prey and water organisms.
Toilsome when infestation is large with continuos emptying of traps – impractical in closed summer houses.
Difficult to arm – crushed fingers or unreleased traps with pinched bait.
Food supply – attracts even more mice.
Sanitary discomfort – messy emptying with risk for infections.

Relatively high investment.
No immediate effect, normally 3 - 20 days delay – longer delays sometimes occur.

1) Up to 12 months is sometimes offered. 2) Valid for equipment with water-resistant speakers alternatively for mole chasers with water protected electronics and with condensation slots. Devices without these features have a very limited life scope.