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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #318070
Title: Effects of postharvest onion curing parameters on bulb rot caused by Pantoea agglomerans, Pantoea ananatis, and Pantoea allii in storage

Author
item Armstrong, Cheryl
item DUNG, J - Oregon State University
item HUMANN, J - Washington State University
item SCHROEDER, B - Washington State University

Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2015
Publication Date: 5/1/2016
Citation: Armstrong, C.M., Dung, J.K., Humann, J.L., Schroeder, B.K. 2016. Effects of postharvest onion curing parameters on bulb rot caused by Pantoea agglomerans, Pantoea ananatis, and Pantoea allii in storage. Plant Pathology. 65:536-544. doi: 10.1111/ppa.12438.

Interpretive Summary: An exceptionally high economic impact results from the loss of onion bulbs during storage because most of the production expenses have already been expended before storage occurs. To help define practices that minimize onion bulb losses caused by storage rots, the impacts of various curing parameters on disease development resulting from infection by Pantoea agglomerans, P. ananatis and P. allii on onion bulb cultivars ‘Vaquero’ and ‘Redwing’ during storage were investigated. Overall, this study showed that both incidence and mean rot severity were similar for bulbs under comparable conditions regardless of the species of Pantoea inoculated. However, factors that significantly reduced storage rot included cultivar (Redwing showed less rot compared to Vaquero bulbs) and curing temperatures set =35°C. For temperatures >35°C, a shorter curing duration (2 days versus 14 days) was shown to decrease the severity of bulb rot due to Pantoea. Together, this information helps provide guidance towards utilizing the curing process as a method to reduce the amount of post-harvest damage resulting from Pantoea.

Technical Abstract: Crop loss of onion bulbs during storage carries an exceptionally high economic impact since a large portion of the production expenses have been expended before storage occurs. Because of this, it is important to define practices that can reduce onion bulb losses caused by storage rots. This study investigates the impact of various curing parameters on disease development resulting from infection by Pantoea agglomerans, P. ananatis and P. allii on onion bulb cvs. ‘Vaquero’ and ‘Redwing’ during storage. Overall, both the incidence and mean rot severity were similar amongst the bulbs under comparable conditions regardless of the species of Pantoea inoculated, although a significant difference was detected between the two onion bulb cultivars (Redwing versus Vaquero). In addition, a significant reduction of storage rot was observed when curing temperatures were =35°C. At temperatures >35°C, a shorter curing duration (2 days versus 14 days) decreased the severity of bulb rot due to Pantoea. This increased understanding of the inter-relationships between the parameters used for curing, and the incidence and severity of bulb rot caused by Pantoea helps provide guidance towards utilizing the curing process as a means to reduce the level of damage resulting from post-harvest storage rot.