In-package fumigation of blueberries using ethyl formate: Effects on spotted-wing drosophila (Drosophila suzukii Matsumura) mortality and fruit quality

Abstract

Ethyl formate (EF) is a food-flavoring agent with a generally regarded as safe (GRAS) status. It is a naturally-occurring insecticidal volatile compound promising as an alternative to synthetic insect pest fumigants that are toxic and/or undesirable to the environment. In this study, an EF precursor (EFP) was investigated as an activated EF release system for in-package fumigation of spotted-wing drosophila (SWD) in blueberries. EF concentration, exposure time, and fruit loading factor had significant (p < 0.05) effects on the mortality of SWD adults. At 22 ± 1 °C, complete control (100 % mortality) of SWD adults was observed after exposing the infested fruits to a package headspace containing 6 mg/L of EF for 4 h at 3 and 6 % (w/v) fruit loading factors, while 4 mg/L EF dosage for 2 h resulted in a similar 100 % mortality at 30 % (w/v) fruit load factor. SWD eggs, larvae, and pupae in blueberries were more tolerant toward EF vapor than the adults, in which 16 mg/L of EF for 24 h was effective for complete control of these stages of the insect. There were no significant (p > 0.05) differences observed in blueberries quality parameters after the EF fumigation treatments. Results from this study suggested that in-package EF fumigation via the EFP system has a potential as a postharvest treatment for SWD control in blueberries. This active packaging approach can be beneficial for streamlining the existing fumigation approach, thereby increasing the available shelf-life of fresh produce.