# trans-α-Necrodyl Acetate: Minor Sex Pheromone Component of the Invasive Mealybug Delottococcus aberiae (De Lotto)

## TL;DR

Scientists discovered a minor sex pheromone component in an invasive mealybug that could help control its population.

## Contribution

Identification of trans-α-necrodyl acetate as a minor sex pheromone component in Delottococcus aberiae with male attractant activity.

## Key findings

- trans-α-necrodyl acetate was identified in the volatile effluvia of D. aberiae virgin females.
- The compound showed male attractant activity in both laboratory and field bioassays.
- The compound is also found in the essential oil of Lavandula stoechas subsp. luisieri.

## Abstract

Many insect species of the superfamily Coccoidea rely on sex pheromones to find their mates and increase their populations. Their pheromone blends are generally composed of irregular monoterpenes, with one or two components. Once known, these substances could be employed to develop control methods to manage these pests and reduce their effects. Recent research has reported the main compound of the sex pheromone of the invasive mealybug Delottococcus aberiae, a seriously damaging pest of citrus in eastern Spain that threatens the Mediterranean area. In the present work, we reinvestigated the composition of the D. aberiae virgin female effluvia by volatile collection, finding an additional minor compound, trans-α-necrodyl acetate. Interestingly, this is not a novel compound; it has been reported as a component of the essential oil of the plant Lavandula stoechas subsp. luisieri. This compound showed male attractant activity by itself; therefore, it may participate in the communication of this species and could be a valuable tool for its control.

Reported in Europe in the early 2000s, Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is an invasive mealybug pest that is causing severe damage to citrus production in eastern Spain. Once its main sex pheromone component was identified in a previous work as (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate 1, the revision of virgin female effluvia is here reported to improve knowledge about the biology of D. aberiae. A new minor component has been identified in the volatile samples collected from virgin females as ((1R, 4R)-3,4,5,5-tetramethylcyclopent-2-en-1-yl)methyl acetate (trans-α-necrodyl acetate, (1R, 4R)-2), a compound also found in the essential oil of Lavandula stoechas subsp. luisieri. Bioassay testing of the activity of this compound showed that a synthetic sample of the racemate (±)-(trans)-2 was attractive to D. aberiae males both in the laboratory and field but with a lower attractant power than enantiopure (1R, 4R)-2 and (±)-(1). The 1:1 mixture of (1R, 4R)-2 and (±)-1 provided a slight additive effect. Further trials are needed to know the pest control potential of this minor compound but the possibility of obtaining this substance from a natural source could pose an important advantage to implement new methods for the sustainable control of D. aberiae.