RNA Interference as Molecular Mechanisms for Insect Pest Management

Insects have recently become increasingly resistant to pesticides and, therefore, their is a need for viable alternatives to curtail the huge yield losses due to insect pests’ damage to crops. RNA interference (RNAi) is a biotechnological technique that can be used to control pests by silencing their critical survival genes. The mechanisms involve the regulation and expression of genes, typically by causing the destruction of specific mRNA molecules. The success of RNAi for agricultural pest control depends on target specificity, gene-silencing efficiency, and the correct choice of delivery method of double-stranded RNA (dsRNA) into the target area of an organism. This chapter further discusses the main methods of dsRNA which include injection, soaking, feeding, transgenic technique, and viral infection among different insect species. More recently, the field application of RNAi for pest control was mainly by host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS). The former involves the silencing of genes in pests and disease pathogens by expressing homologous dsRNA or artificial microRNAs (amiRNAs) in the host plant. While the latter involves the external application of dsRNA on plant leaves and the stem of the target plant. Therefore, RNAi has the advantage of being an innovative, eco-friendly, and sustainable method of pest control that reduces the over-dependency on chemical insecticides and their resistance. However, one of the most challenging scenarios of RNAi technology is producing sufficient amounts of stable dsRNA in plants to achieve conventional transgenesis. In addition, many insects do not respond to exogenously applied dsRNAs, either degrading them or failing to import them into the cytoplasm. Therefore, the use of RNAi methods will contribute immensely towards the development of integrated pest management packages for the control of major insect pests and diseases of various agricultural crops.