IPM Strategies to Reduce Vidalia Onion Losses

Story in Brief

Center rot of onion has emerged as a chronic problem in onion growing regions in the U.S., including Georgia, and it has been responsible for significant economic losses in yield and quality. Presence of multiple sources of inocula (seed, weeds, and insects) and a lack of resistant varieties makes this disease extremely difficult to manage. A collaborative effort between UGA Extension specialists and county Extension agents was initiated using funding from the Specialty Crop Block Grant to evaluate the impact of weed, thrips and foliar P. ananatis control on the management of center rot. Based on field evaluations, they concluded that effective weed control with certain herbicide treatments can reduce center rot severity under field conditions. They also evaluated chemical control for P. ananatis and thrips to manage center rot. They observed that an effective bactericide program, along with a strong thrips management program, is necessary for effective center rot management. An integrated trial was conducted where the best performing herbicide, bactericide and thrips programs were integrated into an IPM program and compared with the grower’s standard. Based on the preliminary economic analysis, the proposed IPM program can result in marketable yield increase of 60 pounds per acre compared to the grower’s standard practice, which can account for $140 increase per acre. If this IPM program is adopted throughout Georgia's 10,000 acres of Vidalia onion, the projected increase in value of this technology will be $1.4 million.

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