A crop-duster spraying<unk>  on a field A Lite-Trac four-wheeled self-propelled crop sprayer spraying<unk>  on a field<unk> s are substances that are meant to control pests. The term<unk>  includes all of the following: herbicide, insecticides (which may include insect growth regulators, termiticides, etc.) nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, antimicrobial, fungicide, and lampricide. The most common of these are herbicides which account for approximately 80% of all<unk>  use. Most<unk> s are intended to serve as plant protection products (also known as crop protection products), which in general, protect plants from weeds, fungi, or insects. As an example, the fungus Alternaria solani is used to combat the aquatic weed Salvinia. In general, a<unk>  is a chemical (such as carbamate) or biological agent (such as a virus, bacterium, or fungus) that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors. Along with these benefits,<unk> s also have drawbacks, such as potential toxicity to humans and other species.
Pesticide
Pollutant
Prebiotic 
Biological agent
Antiseptic
Cold medicine
Insecticide
Querulant