Many new chemicals in pest control are touted as "non-repellent". What does this mean?
A non-repellant chemical has many advantages, specifically when dealing with termites.
Termites forage for food and may come into contact with a chemical barrier around a house in doing so, if the barrier is repellant, that is to say, the termites can detect it and avoid it, then there is a potential for them to locate somewhere around the perimeter of the building where they can enter. Hence, a barrier that is repellent can fail if the chemical has not been applied evenly around the perimeter through all potential entry points.
A non-repellent chemical treated zone does not repel the termites, but instead, allows them to enter the treated soil to such an extent that the termites are affected and after a period of time, they die off. The benefits of this treatment are apparent in the photos above. Not only does it prevent the termites finding the non-treated section of the barrier, but it also can kill many termites due to the delayed action of the chemical. In some instances, the transfer of chemical from one termite to another can be so prolific that the whole colony can be eliminated!