Evaluation of Systematic Spray Programs to Reduce Onion Center Rot Incidence
Applied Research
Savannah Tanner
County Extension Agent
University of Georgia
Swainsboro
Abstract
The bacterial disease, Center Rot (Pantoea spp.) is the leading cause of loss in Vidalia Onions each year. In 2021, local Vidalia Onion agents conducted a survey assessing the need for research into center rot prevention. This survey showed that 94% of producers believe that center rot is a significant issue and over 69% of the respondents lose over $1000 per acre each year. Following this survey and for the past three years, local agricultural agents have evaluated four systematic approaches to center rot incidence in Vidalia Onions including a Low Input, Growers Standard, High Input, and Organic approach. Agents planted Vidalia Onion Varieties ‘Pirate’ or ‘Century’ in 20-ft plots consisting of 4 replications of each treatment with a 3-ft bare-ground buffer between each plot. All applications were made based on the input levels during the growing season. Treatments were applied with a backpack sprayer calibrated to deliver 33 gal/A at 40 psi through TX-18 hollow cone nozzles. Natural infection was relied upon for center rot contamination. Center rot bulb symptoms were assessed 14 days after harvest following incubation at 28? and 50% RH. Marketable yield, input costs, and total revenue were calculated for each treatment. Based on three year field assessments we observed that integrated management practices had an impact on marketable yield. The ‘high input’ treatment revenue was $1237.00 more per acre than the ‘growers standard’ even with similar infections. Organic treatment was also $367.00 more per acre than ‘grower standard’ and on average had an 9.04% increase in center rot incidence. Overall, the ‘high input’ treatment led to greater revenue despite having the greatest input cost.
Poster has NOT been presented at any previous NACAA AM/PIC
This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.
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Authors: Savannah Tanner
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Tanner, S. County Extension Agent, UGA Extension , Georgia, 30401