Pesticide

A pesticide is a chemical, or sometimes biological agent such as a virus or bacteria, used to control, to repel, to attract, or to kill pests, which are organisms, including insects, weeds, birds, mammals, fish, and microbes, that compete with humans for food, destroy property, spread disease, or are considered a nuisance. Pesticides are usually, but not always, poisonous to humans.

Pesticides active against plants and lower level life forms

• bactericides
• herbicides, which kill or prevent the development of weeds
• fungicides, which kill fungi
• plant growth regulators http://www.hclrss.demon.co.uk/class_plant_growth_regulators.html, which prevent excess growth of a plant (for example, prevention of lodging in wheat)
• virucides http://www.hclrss.demon.co.uk/class_virucides.html

It is important to note that using chemical pesticides to eliminate insects works against the over-all goal of eliminating the targeted pest. The natural equilibrium that is maintained between predator/prey relationships swing to an unnatural state. Prey tends to reproduce quickly whereas predator insects have a lag in growth rate dependent on the availability of their food source. After pesticides are employed relatively all insects are killed. The target insect, usually the plant consumer, will return to the system first. There will be significant lag time before its predator returns to the system. Therefore, the returning consumer will have uncontrolled opportunity to feed and breed. Pests may be found in greater numbers weeks after the pesticide use than before. This necessitates the constant cycle of pesticides.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~