Selecting an appropriate target gene is critical to the success of oral RNA interference-based pest control. The selection of target genes has depended on their ability to induce lethality. However, the induction of lethality by oral RNAi is slow-acting, and crop damage can progress during this time. Here, we show that oral RNAi of thedeath-associated inhibitor of apoptosis protein 1(diap1), unlike two conventional target genes, induces acute feeding cessation in the solanaceous pest,Henosepilachna vigintioctopunctatawithin 24 h. We also found that our designed dsRNA has high specificity and does not cause death or reducediap1expression in two non-target insects. Our results suggest thatdiap1is an appropriate target in the context of the rapid reduction of crop damage. We propose that the phenotype of acute feeding cessation should be used as a novel criterion for selecting target genes for RNAi-based pest control.