Mate and host semiochemicals as management tools for Strategus aloeus (Coleoptera: Scarabaeidae) in oil palm crops

Strategus aloeus (Coleoptera: Scarabaeidae: Dynastinae) represents a significant pest of young oil palm crops in Latin America. Although a pheromone had already been identified, its use as a tool for integrated management remained limited. Thus, to elucidate the fuller characterization of the chemical signaling associated with this beetle and its host, the volatile organic compounds (VOCs) released by S. aloeus and the oil palm bulb (Elaeis guineensis) were isolated, identified, and evaluated. The analysis was conducted using gas chromatography coupled with mass spectrometry (GC—MS), and the attractant potential of the compounds was validated by testing their effects on insects’ behavior under laboratory and field conditions. From solvent-assisted extraction (SAE) samples, the compounds 2,4,7,9-tetramethyl-5-decyne-4,7-diol, sec-butyl acetate, and ethyl 4-methyloctanoate in a ratio of 58:34:8 were identified as part of a possible male-specific pheromone. Furthermore, 2-butanone and 3-pentanone were identified as components of the oil palm kairomone using static headspace with solid phase microextraction (HS-SPME) sampling. The laboratory behavioral response of S. aloeus to the 3 male-specific compounds, alone or combined, demonstrated a significant attraction (P < 0.01) of both sexes, indicating their potential involvement in intraspecific interactions, specifically as an aggregation sex pheromone. In field trials, mixtures of 3 to 5 semiochemicals demonstrated high capture rates with a female-biased proportion (80:20). The treatment containing 2-butanone, 3-pentanone, and sec-butyl acetate exhibited the highest efficacy (P < 0.0001).