The <i>HcAmy2</i> Confers the Adaptability of <i>Hyphantria cunea</i> to Multiple Hosts: An Important Target for Constructing Nucleic Acid Pesticide

Robust digestive physiology is crucial for the population outbreaks of <i>Hyphantria cunea</i>. This study elucidated the molecular mechanisms of multihost adaptation in larvae, focusing on α-amylase genes, and developed targeted nucleic acid pesticides. Results showed that <i>HcAmy2</i> was the most highly expressed α-amylase gene in the larval midgut across medium- and low-preference host plants. Silencing the <i>HcAmy2</i> gene significantly reduced larval weight (32.44-57.11%) and increased larval mortality (5.27-37.06%), accompanied by decreased energy metabolism and antioxidant defense level. The constructed chitosan (CS)-encapsulated nucleic acid pesticide, CS-ds<i>HcAmy2</i>, showed high stability, effective silencing, and minimal nontarget effects. It suppressed larval growth and survival across all host plants, and improved the insecticidal activity of coumarin. Taken together, <i>HcAmy2</i> functions as a pivotal digestive gene mediating the formation of multihost plant adaptability in <i>H. cunea</i>, and the nucleic acid pesticide constructed by targeting <i>HcAmy2</i> coffers a promising strategy for environmentally control of<i>H. cunea</i> larvae.