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

Reported in Europe in the early 2000s, <i>Delottococcus aberiae</i> (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 <b>1</b>, the revision of virgin female effluvia is here reported to improve knowledge about the biology of <i>D. aberiae</i>. A new minor component has been identified in the volatile samples collected from virgin females as ((1<i>R</i>, 4<i>R</i>)-3,4,5,5-tetramethylcyclopent-2-en-1-yl)methyl acetate (<i>trans</i>-α-necrodyl acetate, (1<i>R</i>, 4<i>R</i>)-<b>2</b>), a compound also found in the essential oil of <i>Lavandula stoechas</i> subsp. <i>luisieri</i>. Bioassay testing of the activity of this compound showed that a synthetic sample of the racemate (±)-(<i>trans</i>)-<b>2</b> was attractive to <i>D. aberiae</i> males both in the laboratory and field but with a lower attractant power than enantiopure (1<i>R</i>, 4<i>R</i>)-<b>2</b> and (±)-(<b>1</b>). The 1:1 mixture of (1<i>R</i>, 4<i>R</i>)-<b>2</b> and (±)-<b>1</b> 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 <i>D. aberiae</i>.