Role of novel insecticides in crop protection and their selectivity to natural enemies: A review

Abstract

In the present context of pest management in major crops, as the nature of pest pressure evolves, the requirement of new research-based tactics for pest control becomes a continuous process. Insecticide chemistry plays a major, if not dominant role in these developments. In this review, the toxicological aspects of new novel insecticides against crop pests and their selectivity to natural enemies have been discussed. The progress achieved in toxicological research has introduced new insecticides in crop protection during last two decades which are quite different over the existing groups in terms of chemistry and mode of action. It is evident from their mode of action that these chemicals target alternate physiological and biochemical effect. However, it is important to maintain the diversity in chemistry of insecticides for maximizing flexibility, precision and stability in pest management. In recent years, several new insecticide groups viz., neonicotinoids, butenolides, tetronic and tetramic acid derivatives, oxadiazines, diamides, ketoenols, phenylpyrazoles, pyridines, flonicamid, mitochondrial electron transport inhibitor (METI) acaricides, diafenthiuron, tetrazines, oxazolines, and insecticides from soil microorganisms such as avermectins, milbemycins, spinosyns, pyrrole insecticides and insect growth regulators (IGRs) have been discovered and commercialized for agricultural pest management. The ability of these new groups of insecticides to be effective at low rates or doses, high level of selectivity, greater specificity to target pests along with low toxicity to non-target organisms and the environment, replaced many conventional compounds. The conservation of beneficial organisms like natural enemies and pollinators is the fundamental principle of integrated pest management (IPM). Majority of new insecticide groups are safer and fit well into IPM. It is perceived that in the process of entry of new chemical insecticides in crop protection there is a gradual shift from traditional chemicals to selective novel groups which have minimal side-effects on natural enemies of the pests. These selective insecticides have less adverse impact on the conservation and multiplication of bio agents which can be used in a compatible manner with other tools of IPM. The new chemistries are emphasizing to account separately for possible non-target effects on predators, parasitoids, and pathogens. These factors are becoming increasingly important as the agricultural sector moves away from highly persistent broad-spectrum insecticides to more selective rapidly decaying products.