The “cotton boll weevil” (Anthonomus grandis Boheman) is a key pest in America whose larval stage develops within the cotton flower bud. During its development, the larva uses the flower bud as food and as a shelter from predators. This behavior limits the effective control through conventional insecticide applications and biocontrol techniques. Increasing genetic information from insects has allowed the development of new control technologies based on the use of RNA interference (RNAi) to design orally delivered double-stranded RNA (dsRNA) strategies. In this study, we evaluated the effect of continuous oral administration of six specific dsRNA in order to identify an effective target gene for RNAi-mediated control of cotton boll weevil. First, six selected A. grandis gene fragments were amplified and cloned to perform in vivo synthesis of the specific dsRNA, and subsequently, larvae and adults were fed with this dsRNA for 2 weeks. Larvae mortality ranged from 40 to 60% depending on the targeted gene sequence. Indeed, α-amylase and cytochrome p450 dsRNAs were the most effective. Oral administration in adults caused smaller but still significant death rates (15–30%). Thus, the results demonstrated RNAi responses depend on life stages and target genes. The dsRNA ingestion was capable of providing knockdown mRNA levels in cotton boll weevil midgut and this effect was significantly higher in the larval stage. In this study, we present a new report of silencing of midgut genes in A. grandis larva induced by continuously feeding with dsRNA. This potential new tool should be further evaluated in cotton boll weevil control strategies.

“棉铃象鼻虫”（Anthonomus grandis Boheman ）是美洲的主要害虫，其幼虫阶段在棉花花蕾内发育。在发育过程中，幼虫利用花蕾作为食物和躲避捕食者的庇护所。这种行为限制了通过常规杀虫剂应用和生物防治技术的有效控制。增加来自昆虫的遗传信息使得基于使用 RNA 干扰 (RNAi) 设计口服双链 RNA (dsRNA) 策略的新控制技术的发展成为可能。在这项研究中，我们评估了连续口服六种特定 dsRNA 的效果，以确定用于 RNAi 介导的棉铃象鼻虫控制的有效靶基因。一、六选A. Grandis基因片段被扩增和克隆以在体内合成特定的 dsRNA，随后，幼虫和成虫被喂食这种 dsRNA 2 周。取决于目标基因序列，幼虫死亡率在 40% 到 60% 之间。事实上，α-淀粉酶和细胞色素 p450 dsRNA 是最有效的。成人口服给药导致较小但仍然显着的死亡率（15-30%）。因此，结果表明 RNAi 反应取决于生命阶段和目标基因。dsRNA 摄入能够在棉铃象鼻中肠中提供敲低 mRNA 水平，这种效果在幼虫阶段显着更高。在这项研究中，我们提出了一份关于A. grandis中肠基因沉默的新报告通过连续喂养 dsRNA 诱导的幼虫。这种潜在的新工具应在棉铃象鼻虫控制策略中进一步评估。