From ArticleWorld

A pesticide is a chemical substance or mixture of substances that can prevent the life of a pest, destroy a pest, repel a pest or interfere with the lifecycle of any kind of pest. A pest is an organism that competes with humans for food, destroys property or causes disease. An organism that is considered a nuisance can be a pest. Pests can include insects, weeds, birds, fish, worms, microorganisms, mammals or mollusks.


Pesticides have been used for over 2000 years to prevent crop damage. Sulfur was the first known pesticide. Later, arsenic, mercury and lead were used to kill pest infestation in crops. In the 1800s, several natural pesticides were found, such as nicotine (from tobacco), pyrethrum (from chrysanthemums) and rotenone (from the roots of beans).

Synthetic pesticides were introduced in the late 1930s by a gentleman who discovered DDT. It was used widely until it was discovered to block the reproductive abilities of some birds and fish. It was subsequently found to cause birth defects in mammals, including humans. DDT is now banned in many countries. Today, we use 50 times more pesticides than in 1950, which means that 2.5 million tons of industrial pesticides are used on crops per year.


Pesticides occur in specific forms and for specific reasons. Herbicides kill plant substances such as weeds. The most commonly used herbicide is glyphosate, the main ingredient in Roundup®. Bactericides are used against pathogenic bacteria. Fungicides kill fungi that are also pests. Insecticides kill various kinds of insects.

Repellents and attractants work to keep insects, birds and mammals away from certain mammalian pests. There are several means of using animal repellents against animals such as rabbits and deer that can eat vegetation. DEET is an insect repellent most commonly used to rid an area of mosquitoes.

Higher animal forms can have pesticides that directly harm them. Acaricides control spider infestations. Chemosterilants prevent insects from reproducing. Rodenticides and nematicides work against rodents and worms, respectively.


In the U.S., all pesticides that are intended for sale must be registered with the Environmental Protection Agency. Studies must be performed to guarantee safety and effectiveness. Proper labeling is required for all pesticides. Some pesticides are restricted to certified applicators due to their risk if overused by the public. In the U.S., it is against the law to use a pesticide that isn’t in accordance with the specific label for a given pesticide.