Chapter Five - Progress Towards RNAi-Mediated Insect Pest Management

Abstract Gene suppression via RNA interference (RNAi) provides an alternative strategy for insect pest management. The ingestion by insects of double-stranded RNAs targeting essential insect genes can trigger RNAi and lead to growth inhibition, developmental aberrations, reduced fecundity, and mortality. This RNAi response is particularly acute in certain coleopteran species, most notably the western corn rootworm, a devastating pest impacting corn production in the United States. The development of next-generation rootworm-protected corn hybrids includes an RNAi-based trait that provides a mode of action distinct from those of Bacillus thuringiensis insecticidal protein-based traits currently used for rootworm pest management. Unfortunately, many insect species including important lepidoptera and hemiptera pests appear largely recalcitrant in their response to environmental RNA, suggesting biological barriers that thus far limit the utility of RNAi for agricultural pest management. This review will highlight recent efforts to understand the barriers to RNA delivery in recalcitrant insect species, describe recent advances in the commercial development of insect-protected crops and biological insecticides utilizing RNAi, and discuss this strategy in the context of an integrated pest management approach.