Fumigant toxicity of different volatile compounds to eggs and adults of the spotted-wing drosophila (Drosophila suzukii): identifying an environmentally sustainable alternative for post-harvest fumigation

Abstract

The toxicity and environmental impact associated with use of methyl bromide as a post-harvest fumigant resulted in research to find environmentally sustainable alternatives. Trans-cinnamaldehyde (TC), benzaldehyde, allyl isothiocyanate (AITC), hexanal, and ethyl formate (EF) are naturally occurring plant volatile compounds with insecticidal properties. This thesis assessed the fumigant toxicity of these volatile compounds to spotted-wing drosophila (SWD) adults and eggs. All five compounds were toxic to SWD adults with varying degree of mortality depending on concentration, but only AITC was effective against eggs. Allyl isothiocyanate caused 100% mortality of adults and eggs following fumigation exposure for 24 h at a concentration of 0.20 μL/L and 0.50 μL/L air, respectively. These findings suggest the potential of AITC as an environmentally sustainable fumigant alternative that should be considered for post-harvest use in pre- or during-shipment (active packaging) applications.