Understanding the difference between repellent and non-repellent insecticides and which should be used to treat pests is a significant part of pest management. To serve customers most effectively, pest management professionals (PMPs) must have a clear understanding of their customers’ pests to determine the type of treatment to use. The main difference a user will find between repellent and non-repellent insecticides is the length of time it takes for the product to knock down an insect and whether the insect has time to transfer the insecticide to fellow pests or nestmates. Fast acting pyrethroid insecticides are considered repellent products because they create a barrier and act quickly to prevent social insects like ants from maintaining a pheromone trail. The resulting distraction from their trail gives the appearance that they have been repelled, even if a product formulation limits repellency. Slower acting insecticides are categorized as non-repellent products and take longer to knock down an insect. Insects cross over surfaces treated with these insecticides and return to the nest before they are affected, thus maintaining a trail and encouraging more ants to come in contact with the same treatment.