The term pesticide means 'pest killer'. Pesticides are chemicals designed to kill target organisms deemed to be pests because they can contribute to human diseases, destruction of crops, or are household pests like ants and roaches.
The Federal Insecticide, Fungicide and Rodenticide Act (known as FIFRA) defines pesticides as ". . . any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest, and any substance or mixture of substances intended for use as a plant regulator, defoliant, desiccant."
Pesticides can take a variety of forms: liquid, powder, gel bait granular etc. Pesticides manufactured in granular form may be subsequently dissolved in spray tanks and applied as liquid. Others are applied in particle form.