Abstract: An insecticide delivery apparatus may include an insecticide extraction chamber having an outlet adjacent a lower end thereof, and a screen adjacent the outlet for holding a mass of insecticide bearing bodies to partially fill the insecticide extraction chamber. A nozzle may be positioned adjacent an upper end of the insecticide extraction chamber for directing a water stream downwardly therefrom toward the mass of insecticide bearing bodies. An air control device may control the water level and associated head space so that the insecticide bearing bodies are at least partially submerged in the water. The bodies may be churned in the water by action of the stream to enhance delivery of insecticide into the water. The apparatus may provide efficient and cost effective control of a number of insects, such as midge flies, that are prevalent in a trickling filter of a typical wastewater treatment plant.