【目的】 探索几丁质合成酶（Chitin synthase，简称CHS）对西花蓟马Frankliniella occidentalis生长发育的影响，旨在寻找一种潜在的西花蓟马防治靶点。【方法】 克隆西花蓟马的CHS基因，命名为Fochs，采用RNA干扰（RNAi）技术研究其功能。【结果】 Fochs基因开放阅读框全长为4 656 bp，编码1 551个氨基酸，预测分子量为176.02 kD，保守结构域为Glyco-tranf-GTA-type superfamily，西花蓟马Fochs与瓜蓟马Thrips palmi CHS亲缘关系最近。Fochs基因在西花蓟马生长发育的各个阶段均有表达，2龄若虫表达量最高，前蛹次之。沉默Fochs基因120 h后，2龄若虫和前蛹的死亡率均显著增加（P < 0.01），化蛹率和羽化率均显著减少（P < 0.01）；若虫和蛹均出现了表皮皱缩、体型缩小、畸形等变化，对初羽化成虫几乎没有影响。【结论】 几丁质合成酶基因在西花蓟马生长发育过程发挥重要作用，可作为RNAi介导的西花蓟马绿色精准防控的潜在靶标。

 [Aim]  To investigate the impact of chitin synthase (CHS) on the growth and development of Frankliniella occidentalis, aiming to identify a potential target for controlling F. occidentalis. [Methods]  The CHS gene of F. occidentalis was cloned and named Fochs, and its function was investigated using RNA interference (RNAi) technology. [Results]  The full-length open reading frame of the Fochs gene was 4 656 bp, encoding 1 551 amino acids, and the predicted molecular weight was 176.02 kD. The conserved domain was Glyco-tranf-GTA-type superfamily. The phylogenetic tree indicated that the Fochs had the closest genetic relationship with the CHS of Thrips palmi. RT-qPCR results demonstrated that the Fochs gene was expressed at all stages of the growth and development of F. occidentalis, with the highest expression in the 2nd instar nymphs, followed by the pro-pupae. After silencing Fochs for 120 h, the mortality rates of the 2nd instar nymphs and pro-pupae was significantly increased (P < 0.01), while the pupation rate and eclosion rate was significantly decreased (P < 0.01). Both nymphs and pupae exhibited morphological changes such as wrinkled cuticle, reduced body size, and deformity, with almost no effect on newly eclosed adults. [Conclusion]  The chitin synthase gene plays a significant role in the growth and development of F. occidentalis, making it a potential target for precise and environmentally friendly control through RNAi-mediated approaches.