Attraction of the sugarcane billbug, Sphenophorus levis, to vinasse and its volatile composition

Abstract

The expansion of sugarcane plantations in Brazil and the discarding of vinasse into the sugarcane field have been speculated to contribute to the growing population of the billbug Sphenophorus levis. This beetle attacks the root system and forms galleries in rhizomes, causing damage or even the death of host plants. It has been suspected that vinasse, a residue from ethanol production, can release volatiles that are attractive to the insect; however, no study has addressed this hypothesis so far. The aim of this study was to investigate the attractiveness of vinasse to S. levis adults and identify the volatile compounds released by this substance using gas chromatography–mass spectrometry (GC–MS). We found that vinasse was more attractive to S. levis than sugarcane stems, molasses and wastewater under laboratory conditions, but not than cane stems at field conditions. Our GC–MS analysis revealed the presence of primary alcohols, terpenes and organic carboxylic acids in vinasse. When a mixture of the commercial synthetic compounds identified in the chemical analysis was tested in the laboratory, a strong attraction of the insects to the mixture was observed. Our results help to explain how vinasse can contribute to the infestations of S. levis in sugarcane fields and shed new light on the development of strategies to control this pest using chemical attractants.