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The RNA interference (RNAi) triggered by short/small interfering RNA (siRNA) was discovered in nematodes and found to function in most living organisms. RNAi has been widely used as a research tool to study gene functions and has shown great potential for the development of novel pest management strategies. RNAi is highly efficient and systemic in coleopterans but highly variable or inefficient in many other insects. Differences in double-stranded RNA (dsRNA) degradation, cellular uptake, inter- and intracellular transports, processing of dsRNA to siRNA, and RNA-induced silencing complex formation influence RNAi efficiency. The basic dsRNA delivery methods include microinjection, feeding, and soaking. To improve dsRNA delivery, various new technologies, including cationic liposome–assisted, nanoparticle-enabled, symbiont-mediated, and plant-mediated deliveries, have been developed. Major challenges to widespread use of RNAi in insect pest management include variable RNAi efficiency among insects, lack of reliable dsRNA delivery methods, off-target and nontarget effects, and potential development of resistance in insect populations. 

The E93 transcription factor is a member of helix‐turn‐helix transcription factor family containing a Pip‐squeak motif. This ecdysone primary response gene was identified as a regulator of cell death inDrosophila melanogasterwhere it is involved in ecdysone‐induced autophagy and caspase activity that mediate degeneration of larval tissues during metamorphosis from larva to pupa. However, its function in adult insects is not well studied. To study E93 function in the red flour beetle,Tribolium castaneum, double‐stranded RNA (dsRNA) targeting E93 (dsE93) was injected into newly emerged adults. Knockdown of E93 caused a decrease in the synthesis of vitellogenin (Vg), oocyte development, and egg‐laying. Sequencing of RNA isolated from adults injected with dsE93 and controldsmalE(dsRNA targetingEscherichia coli malEgene) followed by differential gene expression analysis showed upregulation of genes involved in the metabolism of reserved nutrients.E93knockdown induced changes in gene expression resulted in a decrease in Vg synthesis in the fat body and oocyte maturation in ovaries. Mating experiments showed that females injected with dsE93 did not lay eggs. Knockdown ofE93caused a reduction in the number and size of lipid droplets in the fat body when compared with that in control beetles injected withdsmalE. These data suggest that during the first 2–3 days after the emergence of adult females, E93 suppresses genes coding for enzymes that metabolize reserved nutrients until initiation of vitellogenesis and oogenesis.