A method of formulating and using a microencapsulated insecticide with an extended field life after application of insecticidal activity. These methods include the steps of forming a microcapsule that includes at least one organophosphate insecticide and at least one non-volatile compound such as an esterified fatty acid that is at least partially surrounded by a polymer shell. These formulations can be used to control insect populations by singular or periodic applications of the microcapsule microencapsulated formulations to areas adjacent to insect populations.