Abstract

BACKGROUND In recent years, Monolepta hieroglyphica has become a destructive pest threatening food security in northeastern China, where M. hieroglyphica adults inflict substantial yield losses through feeding on young leaves, silks and sometimes on developing kernels from maize. Plant-mediated RNA interference (RNAi) has proven to be a promising tool for sustainable pest management. Thus, specific and effective RNAi target genes for M. hieroglyphica management are needed. RESULTS Using homology-based searching of the M. hieroglyphica genome, we identified two chitin synthase genes, and named them MhCHS1 and MhCHS2 , respectively. MhCHS2 was found to be expressed in the midgut of M. hieroglyphica . We found that after feeding on transgenic maize expressing MhCHS2 double-stranded RNA (dsRNA) for 2 days, the expression of MhCHS2 was significantly reduced, and the formation of peritrophic membrane was inhibited in M. hieroglyphica . Notably, after feeding on maize expressing MhCHS2 dsRNA, half of M. hieroglyphica died within 4 days, with the majority succumbing by 7 days. Maize expressing MhCHS2 dsRNA exhibited a high degree of resistance to M. hieroglyphica . CONCLUSION These findings further validate the essential role of MhCHS2 in maintaining formation of the peritrophic membrane and ensuring organism survival in M. hieroglyphica . This study suggests that MhCHS2 might be an ideal RNAi target for pest management, and maize expressing MhCHS2 dsRNA could be a potential and effective strategy for M. hieroglyphica control. © 2026 Society of Chemical Industry.