Leaves of the yerba mate tree, Ilex paraguariensis St. Hil. (Aquifoliaceae), are dried and minced to produce one of the most popular teas of South America, known with different names (yerba mate, chimarrão or tereré) depending on the region of cultivation and techniques of preparation. The moth Thelosia camina occurs as an important pest of this culture. Defoliation caused by this Lepidoptera occurs on the most important phase of plant grown, affecting seriously the production. The pheromone was extracted from female pheromonal glands by dissection and solvent extraction. GC-EAD assays employing male antenna showed the presence of nine bioactive compounds in extracts from females. The chemical structure of these compounds was studied by analyzing their chromatographic profiles, mass (GC-MS) and infrared spectra (GC-FTIR), as well as analysis of microderivatization products. The spectroscopic and chromatographic information obtained for the three major compounds indicated that the compounds referred to an aldehyde, an alcohol and an ester both linear dienes, with 18 carbon atoms. The FTIR spectra of all these three dienes showed a pair of well conserved bands at ~3010 and ~3040cm-1 characterizing the double bonds as conjugated and containing a Z,Z configuration. The structure of the six additional compounds were proposed as stereoisomers of the Z,Z dienes based on their MS and FTIR spectra. The structure of the three major compounds were proposed as (13Z,15Z)-octadeca-13,15-dienal, (13Z,15Z)-octadeca-13,15-dien-1-ol and (13Z,15Z)-octadeca-13,15-dien-1-yl acetate. The 13Z,15Z; 13E,15E; 13E,15Z and 13Z,15E isomers of the alcohol, aldehyde and acetate were synthesized by classical approaches, with Sonogashira couplings as key steps. The synthetic compounds were used to prove the proposed structures and also to perform initial field bioassays which showed the attractiveness of the synthetic blends to T. camina males for only the Z,Z isomers or the mixture containing the other stereoisomers.

Identification, synthesis and initial field evaluation of the sex pheromone produced by Thelosia camina (LEPIDOPTERA:EUPTEROTIDAE)

2019 Spring National Meeting

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