Location: Crop Improvement and Protection ResearchTitle: Response of Aspergillus flavus spores to nitric oxide fumigations in atmospheres with different oxygen concentrations
Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2019
Publication Date: 6/12/2019
Citation: Liu, Y., Oh, S., Jurick II, W.M. 2019. Response of Aspergillus flavus spores to nitric oxide fumigations in atmospheres with different oxygen concentrations. Journal of Stored Products Research. 83:78-83. https://doi.org/10.1016/j.jspr.2019.06.001.
Interpretive Summary: Nitric oxide (NO) is a new fumigant for postharvest insect pest control. NO fumigation must be conducted under ultralow oxygen conditions to prevent NO from reacting with O2 to form nitrogen dioxide (NO2). However, both NO and NO2 have antimicrobial property and O2 levels in NO fumigation can be regulated to have desired levels of NO and NO2 to potentially control both pests and pathogens. In this study, Aspergillus flavus spores were subjected to NO fumigations under different O2 levels to expose spores to different levels of NO2 as well as NO for three hours at 15°C. Effective inactivation of spores was achieved in three treatments with 0.1% NO2 and about 1% NO. This study showed that NO fumigation was effective in controlling A. flavus spores and NO fumigation has potential to control insect pests and postharvest plant pathogens such as A. flavus.
Technical Abstract: Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. NO fumigation must be conducted under ultralow oxygen conditions because NO reacts with O2 to produce nitrogen dioxide (NO2). In this study, NO fumigations under different O2 concentrations were conducted on Aspergillus flavus spores to determine effectiveness of NO and NO2 in inactivating spores. Spores on gridded cellulose filter discs in Petri dishes were subjected to 6 fumigation treatments including a control with varying levels of NO under different O2 conditions for 3 h at 15°C. The discs with spores were then cultured on Aspergillus Differentiation medium plates after fumigation for 4 days at 25°C to count A. flavus colonies. Untreated control discs each had over 50 A. flavus colonies. Three fumigation treatments with 0.1% NO2 or 1.0% NO caused complete inactivation of A. flavus spores. The study demonstrated that NO fumigation with certain levels of NO2 can effectively inactivate A. flavus spores. The results suggest that NO fumigation has potential to be an alternative treatment to control both pests and microbes on stored products.