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

Abstract

The spherical mealybug, Nipaecoccus viridis (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 trans-α-necrodol, of unknown chirality, obtained from essential oil of Spanish lavender, Lavandula luisieri. To determine the chirality of the sex pheromone, here, we synthesize the γ-necrodyl acetate enriched in (+)-(S)-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 (−)-(R)-enantiomers. Bioassays conducted in the lab and field show that males are attracted to (−)-(R)-γ-necrodyl isobutyrate alone.

Recent advances in the synthesis of insect pheromones: an overview from 2013 to 2022

“…During this period, the synthesized isoprenoid pheromones were identified from Necrodes surinamensis (Col., Silphidae): 220 , Maconellicoccus hirsutus (Hem., Pseudococcidae): 221 , Anthonomus rubi (Col., Curculionidae) and Planococcus ficus (Hem., Pseudococcidae): 222 , 210,211 Thrips palmi (Thy., Thripidae): 223 , 212 Planococcus kraunhiae (Hem., Pseudococcidae): 224 , 213 Dysmicoccus neobrevipes (Hem., Pseudococcidae): 225 , 214 Leptinotarsa decemlineata (Col., Chrysomelidae): 226 , 215–220 Lasius meridionalis (Hym., Formicidae): 227 , 221,222 Ips confuses (Col., Curculionidae): 228 and 229 , 223 Urolepis rufipes (Hym., Pteromalidae): 230 , 224 Solenopsis invicta (Hym., Formicidae): 231 , 225 Solenopsis invicta (Hym., Formicidae): 231 and 232 ; 226 Astyleiopus variegatus (Col., Cerambycidae): 233 and 234 , 227 Amblypelta lutescens (Hem., Coreidae): 235 , 228 Monomorium pharaonis (Hym., Formicidae): 236 and 237 , 222 Aonidiella aurantia (Hem., Diaspididae): 238 229 Pseudococcus calceolariae (Hem., Pseudococcidae): 239 , 230 Anthonomus grandis (Col., Curculionidae): 240 , 231–233 Aspidiotus nerii (Hem., Diaspididae): 241 , 234 Pseudococcus longispinus (Hem., Pseudococcidae): 242 , 235–237 Dysmicoccus brevipes (Hem., Pseudococcidae): 243 , 238,239 Nipaecoccus viridis (Hem., Pseudococcidae): 244 , 240,241 Pseudococcus baliteus (Hem., Pseudococcidae): 245 , 242 Dolichovespula maculate (Hym., Vespidae): 246 , 243 Tibraca limbativentris (Hem., Pentatomidae): 247 , 244 Oebalus poecilus (Hem., Pentatomidae): 248 , 245 Murgantia histrionica and Halyomorpha halys (Hem., Pentatomidae): 249 , 245,246 Anoplophora malasiaca (Col., Cerambycidae): 250–252…”

Synthesis of β-Methyl Alcohols: Influence of Alkyl Chain Length on Diastereoselectivity and New Attractants of Rhynchophorus ferrugineus

“…Pheromones are a family of semiochemicals that significantly influence the survival and social organization of insects . The use of insect pheromones as an alternative to conventional pesticides, which have negative impacts on the environment and other organisms, is of particular relevance to integrated pest management (IPM) strategies. − Several methods can be used to identify the components of new attractants. The first method is isolation and extraction of pheromones by solvent extraction or aeration (volatile collection) .…”