It is important to note that ants forage from the nest looking for food and water. They mark their routes or trails with pheromones so that they can find their way to the nest, food and water. If you disturb these pheromone trails the ants will not be able to find their way back to the nest and if the foraging ants do not return to the nest then the original nest may bud or split up and the whole life cycle will be sped up to produce more ants and the net result will be that you will have more ants to deal with than what you originally had.
It is important not to spray chemicals on these pheromone trails as this will destroy the pheromone trails and you may only kill some foraging ants but will disturb the whole nest leading to budding. By spraying the foraging worker ants you will only destroy about 5-10% of the colony and you will accomplish very little.
The ideal way to control ants is to provide them with baits formulated from proteins and carbohydrates to take down into their nests and to distribute these by food sharing or tropholaxes. In this way you will use the behaviour of the ants to get your baits deep into the nest and thereby controlling the ants with the ants themselves.
The following steps must always be used when contemplating a treatment program for ants:
A full inspection of the facility must be done to determine the extent of the infestation noting the position of the nest, water and food source. These locations will normally be linked with foraging trails or pheromone trails. You need to know where the ant is living before you can treat them effectively. The ant must be identified so that the correct treatment procedure can be determined. Remember that some ants prefer protein based food while others prefer carbohydrates. This is important as some bait is protein based and some of your liquid gel baits are carbohydrate based.
Direct drenching of the colony in its nesting place can be performed if you know where it is. It is important not to disturb the pheromone trails with chemical sprays as this will lead to budding. Remember you need to take away the nesting site or material and remove the food and water source. This can only be done by focussing on hygiene and sanitation and excluding the ants from the structure.
Follow up. Ant management is not a once off treatment. You will only be successful if you keep following up and replenish baits and treatments as you are normally working with hundreds of thousands of ants.