Insecticides are substances – either naturally derived or synthesized by the chemical industry – that are used for their toxic, caustic or otherwise negative impact on insect life. In terms of their mode of action, insecticides are classified as: “contact” (take action when brought into direct contact with insects), “ingested” (take action after oral introduction) or “inhaled” (take action via the respiratory tract). Modern insecticides often have the capability of utilizing different modes of action simultaneously.