METABOLIC RESISTANCE

Metabolic resistance is due to increased activity of metabolic enzymes, of which esterases and oxidases are the most important. Unlike target-site resistance, metabolic resistance is often very broad, giving resistance against many different insecticides, perhaps even many different classes of insecticides.

Examples of both enzyme groups may be capable of cleaving insecticides, rendering them harmless before reaching the target-site. In addition, esterases can be capable of sequestering the insecticides.

Unlike target-site resistance, control cannot be regained simply by using an insecticide from a different chemical class. In this instance, a chemical can be used to inhibit the enzymes and protect the insecticide; this is the usual way in which an insecticide synergist would work removing the protective effect of the defence enzymes, thus increasing the effect of the insecticide.