Abstract The full‐length c DNA (2320 bp) encoding a putative iron‐binding transferrin protein from H elicoverpa armigera was cloned and named H a T rf . The putative H a T rf sequence included 670 amino acids with a molecular mass of approximately 76 kDa. Quantitative PCR results demonstrated that the transcriptional level of H a T rf was significantly higher in the sixth instar and pupa stages as compared with other developmental stages. H a T rf transcripts were more abundant in fat bodies and in the epidermis than in malpighian tubules. Compared with the control, the expression of H a T rf increased dramatically 24 h after treatment with 2‐tridecanone. Apparent growth inhibition with a dramatic body weight decrease was observed in larvae fed with H a T rf double‐stranded RNA (ds RNA ), as compared with those fed with green fluorescent protein ds RNA . RNA interference of H a T rf also significantly increased the susceptibility of larvae to 2‐tridecanone. These results indicate the possible involvement of H a T rf in tolerance to plant secondary chemicals.