Identification, Synthesis, Behavioral Activity, and Field Assessment of Components of the Female-Produced Sex Pheromone of Helopeltis theivora (Hemiptera: Miridae), a Devastating Pest of Tea

Abstract

Helopeltis theivora is a major pest of tea, cocoa and cashew, and increasing insecticide resistance highlights the need for sustainable alternatives such as pheromones. Previous studies failed to identify female pheromone components attractive to males in the field. Re-examination of female extracts by gas chromatography with electroantennographic detection (GC–EAD) revealed a single active compound, identified by GC–MS as octyl 3-(butanoyloxy)butanoate (III). Enantioselective analysis showed females produce both (3R)-and (3S)-enantiomers. Two related but EAD-inactive compounds, hexyl (3R)-3-(butanoyloxy)butanoate (II) and octyl butanoate (I) were identified. Both enantiomers of (III) were EAD-active, but individually induced minimal male orientation, whereas blends triggered strong orientated flight and contact. Field trials confirmed that 2:1 or 1:1 blends of (3R)- and (3S)-(III) captured significantly more males than single enantiomers. Adding (I) had no effect, while (II) may increase catches. These findings provide a chemically defined, field-validated basis for monitoring and managing this important pest.