Some pesticides are non-lethal to the target pest. Contact pesticides have to reach their target directly to be effective. Systemic pesticides move from where they are applied to other parts of the plant to reach their target. The route that brings a pesticide in contact with the target pest depends on the nature of the pesticide, how it is applied and the type of environment in which the pesticide is placed. Common application methods include spraying, fumigating and baiting.
Many pesticides are contact pesticides.
Other pesticides are systemic in action. Similarly, blood anticoagulant rodenticides in baits take effect once they have been transferred from the digestive system to the bloodstream of rats. Pesticide persistence Some pesticides are residual in action and continue to be effective for days, weeks or months after their application. Many modern pesticides do not persist for long in the environment. They act quickly and are then degraded to non-toxic substances by chemical or microbial processes.