Mode of action of pesticides and the novel trends – A critical review

The mode of action of pesticides is extremely fascinating because the subject covers so many fields of biology and chemistry and has many practical implications. To understand how pesticides work (their mode of action), it is necessary to understand how the pests’ targeted systems normally function. It is also helpful to understand how human systems function in order to see similarities and differences between humans and the pests we try to control. Another reason, it is important to understand the modes of action of the pesticides we use, is to prevent development of pesticide resistance in the target pest(s). Using pesticides with the same modes of action contributes to this problem by killing the susceptible pests and leaving only those with resistance to the entire class of pesticides that work through similar mechanisms. Development of pest resistance can be avoided or delayed by rotating pest control chemicals that work through different modes of action. To be acceptable, pesticides must not have strong toxicity toward non-target organisms, especially humans. Yet, to be efficient, they must be highly toxic toward their intended targets. The mechanism of this type of selectivity is often the targeting of a molecular target site that is found only in the pest or, if in other organisms, is particularly vulnerable in the pest; e.g., an enzyme form that is significantly different from that of other organisms. Natural toxins are a source of new chemical classes of pesticides, as well as environmentally and toxicologically safer molecules than many of the currently used pesticides. Furthermore, they often have molecular target sites that are not exploited by currently marketed pesticides.