Here are some common kinds of pesticides and their function


Algicides
Control algae in lakes, canals, swimming pools, water tanks, and other sites.
Antifouling agents
Kill or repel organisms that attach to underwater surfaces, such as boat bottoms.
Antimicrobials
Kill microorganisms (such as bacteria and viruses).
Attractants
Attract pests (for example, to lure an insect or rodent to a trap). (However, food is not considered a pesticide when used as an attractant.)
Biocides
Kill microorganisms.
Disinfectants and sanitizers
Kill or inactivate disease-producing microorganisms on inanimate objects.
Fungicides
Kill fungi (including blights, mildews, molds, and rusts).
Fumigants
Produce gas or vapor intended to destroy pests in buildings or soil.
Herbicides
Kill weeds and other plants that grow where they are not wanted.
Insecticides
Kill insects and other arthropods.
Miticides (also called acaricides)
Kill mites that feed on plants and animals.
Microbial pesticides
Microorganisms that kill, inhibit, or out compete pests, including insects or other microorganisms.
Molluscicides
Kill snails and slugs.
Nematicides
Kill nematodes (microscopic, worm-like organisms that feed on plant roots).
Ovicides
Kill eggs of insects and mites.
Pheromones
Biochemical used to disrupt the mating behavior of insects.
Repellents
Repel pests, including insects (such as mosquitoes) and birds.
Rodenticides
Control mice and other rodents.

The term pesticide also includes these substances

Defoliants
Cause leaves or other foliage to drop from a plant, usually to facilitate harvest.
Desiccants
Promote drying of living tissues, such as unwanted plant tops.
Insect growth regulators
Disrupt the molting, maturity from pupil stage to adult, or other life processes of insects.
Plant growth regulators
Substances (excluding fertilizers or other plant nutrients) that alter the expected growth, flowering, or reproduction rate of plants.