Absolute Configuration of the Spherical Mealybug Sex Pheromone, γ-Necrodyl Isobutyrate: Chemoenzymatic Synthesis and Bioassays.

The spherical mealybug, (Hemiptera: Pseudococcidae), is a major global pest causing feeding damage to leaves and fruits of citrus varieties, soybean, mango, pomegranate, and grapevines. Females of the mealybug release a sex pheromone that was identified recently as a mixture of γ-necrodyl isobutyrate and γ-necrodol. The identification required synthesis based on a natural source of -α-necrodol, of unknown chirality, obtained from essential oil of Spanish lavender, . To determine the chirality of the sex pheromone, here, we synthesize the γ-necrodyl acetate enriched in (+)-()-enantiomer and separate the enantiomers using a lipase enzyme. We confirm that the natural components, both in the mealybug and in the lavender essential oil, consist of (-)-()-enantiomers. Bioassays conducted in the lab and field show that males are attracted to (-)-()-γ-necrodyl isobutyrate alone.