Oviposition Behavior of Ectropis grisescens Mediated by Volatile Cues and Development of Attractant Blends

Moths rely on plant volatiles to locate the appropriate hosts for egg-laying. Developing attractants based on plant volatiles offers an alternative to chemical pesticides. We found that Ectropis grisescens, the major tea pest in China, prefers larva-infested tea plants over healthy plants. We identified herbivore-induced plant volatiles (HIPVs) in E. grisescens larvae and designed 14 attractant formulations based on the known flower volatiles and these HIPVs. Of these, formulas 8 (a 2:2:2:3 blend by volume of phenylethyl alcohol, phenylacetaldehyde, linalool, and (Z)-3-hexenyl salicylate in pure solution) and 14 (a 1:1:1 blend by volume of phenylacetaldehyde, linalool, and (Z)-3-hexenyl salicylate in pure solution) demonstrated high trapping efficacy in E. grisescens adults in laboratory and field trials. These blends also strongly attracted nontarget pests, such as Amata germana and Spodoptera litura, with 44 and 6 individuals captured per trapping event, respectively. Further optimization confirmed that the best field performance was achieved using Bioglobal as the dispenser material, pure solution loading of the attractant, and deployment of the trap level at the tea plant canopy. This study identified effective attractant formulations and optimized their application, providing a practical, eco-friendly strategy for managing E. grisescens and associated pests in tea plantations.