The Georgia Soybean Rust and Fungal Disease Sentinel Plot Monitoring Program to Include Field Trial to Assess New Fungicides and Nematicides:

Reintroduction of Asian soybean rust in 2020 was detected earlier in Georgia than at any time since 2006. Asian soybean rust was also detected early in the state in 2021 and again in 2022 (6 June, Lowndes County). Results from a 2021 fungicide trial conducted on the UGA Coastal Plain Experiment Station in Tifton demonstrated that a single, timely fungicide application increased yields by over 10 bu/A. Despite early detection in 2022, soybean rust was slow to spread (detection noted on www.soybeanipmpipe.org) but was eventually identified in Union County. Also, failure to apply fungicides in some commercial fields, despite recommendations from UGA Extension to do so, resulted in significant yield loss in some southern counties.

Detection of soybean rust occurred through monitoring of sentinel plots funded by soybean producers in the state through the Georgia Commodity Commission for Soybeans. Soybean rust continues to be a significant threat for soybean producers across the southern United Sates; the early detection and subsequent warning provided soybean producers with the information to protect their crop from significant yield loss. Given that the availability of some fungicides is likely to be tight during the 2023 season and cost of fungicides is likely to increase, it has never been more important for UGA Extension to be able to provide growers with effective information on timing of fungicide applications to protect yield and minimize costs. Climate for the 2022-2023 winter is predicted to be a La Niña Enso Phase for the third consecutive time, which could mean warmer and drier conditions for states in the southeastern USA. Such conditions, if they occur, would predispose our 2023 soybean crop to earlier impact from soybean rust.

Despite the continued importance of Asian soybean rust to production in the southern United States, Georgia remains the only with a vibrant and active sentinel plot program. Information detected from our sentinel plot program has become critical to not only our soybean producers, but to producers in other states as well.

The first objective of this proposed program is to develop, implement, monitor, and report on the results from a sentinel plot monitoring program for Asian soybean rust and other diseases of soybean. Sentinel plots will be established across Georgia in 2022 and monitored appropriately throughout the field season for the development of Asian soybean rust. DATA WILL BE REPORTED TO THE NEW iPiPE Extension web site. The second objective is to establish field trials at Attapulgus and in Tifton to compare efficacy of new, generic fungicide formulations for the control of rust and other fungal diseases of soybean.

Soybean plots (to include varieties from three different maturity groups) will be planted at locations across the state in April of 2022. Bi-weekly monitoring of these plots will commence in May and weekly monitoring will begin in June as the soybean plants approach flowering. The leaves from soybean and kudzu plots will be brought to the laboratory in Tifton where they will be analyzed and the data will be recorded and uploaded to the USDA Soybean Rust monitoring web site. In total, at least 25 plots (soybean and kudzu) will be monitored across Georgia in 2023.

Replicated fungicide field trials will be established in late May of 2023 and treated with appropriate fungicides at the R1 (bloom) and R3 (pod set) stages to assess for efficacy of disease control.

Information detected from our sentinel plot program has become critical to not only our soybean producers, but to producers in other states as well. Dr. Bob Kemerait and his Extension program remain responsible for coordinating and implementing the state’s Asian Soybean Rust Sentinel Plot Program which provides an early-warning system for growers in Georgia and throughout the United States. At the conclusion of the 2016 season, national funds, e,g, the National Soybean Board, were no longer available. Although Asian soybean rust has not been a serious production problem outside of the southeastern United States, soybean producers in Georgia need to be prepare to manage this disease annually.

Failure to follow fungicide recommendations in 2022 certainly resulted in yield loss in some commercial fields in southern Georgia.

It is absolutely certain that Asian soybean rust will remain an important concern and limiting factor for growers in our state into the future.