# Isolation and Identification of the Sex Pheromone of Evergestis extimalis Scopoli (Lepidoptera: Pyralidae)

## TL;DR

Researchers identified the sex pheromone of Evergestis extimalis, a pest in Chinese rape fields, to reduce pesticide use and support ecological pest management.

## Contribution

The study identifies E11-14Ac as the main sex pheromone component of E. extimalis and demonstrates its effectiveness in attracting males.

## Key findings

- Female E. extimalis pupae have a distinct longitudinal abdominal crack absent in males.
- E11-14Ac was identified as the primary pheromone component from female sex glands.
- E11-14Ac showed stronger attraction to male E. extimalis in field trials compared to other attractants.

## Abstract

Evergestis extimalis is a major destructive pest in spring rape fields on the Qinghai Plateau in China. At present, chemical pesticides are widely applied in agricultural production to control this species. To protect the agricultural and pastoral ecosystems of the Qinghai–Tibet Plateau—known as the world’s third pole—and to reduce pesticide usage, we identified the sex pheromone of this pest, developed pheromone lures, and preliminarily assessed their trapping effectiveness in field trials. This study provides a basis for the biological and ecological management of this pest.

In Qinghai Province, Evergestis extimalis is an important pest of spring rape and is primarily controlled using chemical pesticides. Sex pheromones offer an alternative method for pest management in relatively non-polluted environments. In this study, the sex of E. extimalis pupae was identified, followed by isolation and structural characterization of female pheromone components using GC-EAD and GC-MS. A field attraction assay was then performed. The results showed that female pupae possess a longitudinal crack on the upper central ventral surface of the eighth abdominal segment, which connects the seventh and ninth abdominal segments. The two sides of this crack are open and flat, without protruding semicircles. Male pupae lack this longitudinal crack on the eighth abdominal segment but display one on the central ninth ventral segment, accompanied by semicircular tubercles on each side. The primary component extracted from female sex glands was identified as E11-14Ac. In field trials, E11-14 displayed a stronger attractive effect on E. extimalis males than the other tested attractants. In conclusion, E11-14Ac was preliminarily identified as the main component of the sex pheromone of E. extimalis, providing a foundation for its control using sex pheromones.