To assure that the materials used by the PCMCD remain effective and work to their best advantage, it is important to monitor the mosquitoes for resistance to these products. To do this, mosquito larvae are collected from the wild, reared to the adult stage and then treated with known concentrations of insecticides. This determines the susceptibility of Pasco County mosquitoes to each insecticide used by the District. In this way, the minimum dosage necessary for adequate control is determined and also reveals when resistance to a particular insecticide is developing.

District research and development programs are designed to evaluate the efficacy of new commercial products, evaluate the efficacy of application techniques and equipment, and develop novel insecticide and herbicide delivery systems. A number of insecticides, application equipment and techniques now in world-wide use were originally tested or developed in Pasco County by District personnel.