Asian soybean rust was detected earlier than expected in 2009 on a farm in Jeff Davis County, GA, east of where it was believed to be based on scouting reports. A field day was held to educate farmers on the importance of timely fungicide application, as the infected farm that applied fungicides late suffered yield loss, while a neighbor who applied earlier experienced little loss. The early detection highlighted the need to refine fungicide timing recommendations based on more localized scouting rather than regional reports alone.

1. Initiation of Fungicides for Control of Asian Soybean Rust:
A New Perspective from Jeff Davis County
Varnedore,* T.1, Kemerait, R.C.2, Whitaker, J.R.3
1Jeff Davis County Extension Coordinator, UGA Cooperative Extension, Hazlehurst, GA. 31539
2Extension Pathologist, UGA Cooperative Extension, Tifton, GA 31793
3Extension Agronomist-Soybeans, UGA Cooperative Extension, Statesboro, GA 30460
Abstract: Response:
Over the last five years, Asian soybean rust has continued to be a major concern to Georgia’s soybean After Asian soybean rust was detected on this particular farm in Jeff Davis County on September 4th, the
growers. During this time, considerable research and work has gone into developing the means to track farmer followed UGA Cooperative Extension recommendations for controlling this problem. A neighbor,
the movement of soybean rust across the soybean growing regions This protocol (sentinel plots) was
regions. unaware of the presence of Asian soybean rust in the area sprayed a preventative fungicide during the
area,
implemented to provide growers with the optimal warning to protect their crop with fungicides. Early last week of August. This was a week prior to the discovery of the rust in Jeff Davis County. On
detection of Asian soybean rust is critical for the management of this explosive disease in soybean September 30th, UGA Extension pathologist and local county agent visited the field where rust was initially
production. According to reports from sentinel plots east of I-75 in Georgia, Asian soybean rust had not found in Jeff Davis County. An observation was made that this farmer had suffered yield loss in his
been confirmed in Eastern Georgia prior to September 2009. At this time, it was determined that a soybeans because his fungicide application was applied after rust was already in the field. However, the
commercial field in Jeff Davis County, Georgia displayed the first signs of infestation from Asian soybean neighboring farmer experienced almost no yield loss from Asian soybean rust, likely because of his earlier
rust east of I-75. As a result of this discovery, it has been determined that sentinel plots alone will not fungicide application. Arial photos showed drastic differences in the surrounding fields with the earlier
ultimately protect farmers from Asian soybean rust. fungicide application compared to the field sprayed after rust infestation.
Bushels of Beans Needed to Pay Jeff Davis County Soybean Acres
Objective: for Fungicides
Headline Folicur Non-Treated
The primary objective of this program in Jeff Davis County was to educate farmers, Extension personnel
2
and industry representatives about the importance of early detection of Asian soybean rust and the critical Non-
Treated, Headline,
importance of timely fungicide applications to manage this disease. 1.5 Headline 1000, 1500,
1.68 25% 37%
1
As of September 8, 2009
Folicur Folicur,
0.5 0.71 1500,
38%
0
Headline Folicur
Results:
*Map #1
y y g , y g , g
A soybean rust field day was organized to educate farmers, county agents, consultants and agricultural
industry personnel the importance of timely fungicide application to control Asian soybean rust in Georgia.
Twelve Georgia counties across the state were represented at the Jeff Davis soybean rust field day. This
find will also assist UGA Extension specialist and county agents in updating recommendations on timing of
fungicide applications for controlling Asian soybean rust for Georgia farmers. Based upon the discovery of
Asian soybean rust in Jeff Davis County in 2009; recommendations in Georgia for protecting soybeans
*Map #2 with fungicides in the future will be based upon the results from scouting of sentinel plots and the more
Leaves with soybean rust Microscopic view of soybean conservative potential for the disease to spread quickly beyond known locations infested with this disease.
rust pustules Detection of soybean rust in Jeff Davis Also producers realized that for less than the price of two bushels of soybeans, fungicides can prevent the
County, GA made public in USA
Situation: *Maps obtained from www.sbrusa.net loss of 10 to 15 bushels per acre.
As of September 8 2009 soybean rust had not been found in any sentinel plots east of I-75 in Georgia
8, 2009, Georgia.
Based upon this data, Dr. Bob Kemerait, Extension plant pathologist, advised that a fungicide application
to control rust in the eastern portion of the state was not critical at that time. A farmer in Jeff Davis County
alerted his county agent of a problem with his soybeans. After observing the field, samples were brought
back to the county agent’s office and leaves were found to be heavily infested with what appeared to be
Asian soybean rust. Samples were forwarded to UGA Cooperative Extension Pathology Diagnostic Lab
where Asian soybean rust was confirmed. This find was significant as: a) this was the first Asian soybean
rust detected in eastern Georgia in 2009, b) commercial soybean acreage was now threatened by this
disease, and c) many soybean growers had not yet protected their crop with a fungicide.
Soybean R t Fi ld D - O t b 8, 2009
S b Rust Field Day October 8 Extension personnel explaining soybean
Late fungicide application
rust to local farmer
Conclusion:
Early detection of Asian soybean rust is critical for the management of this explosive disease in soybean
production. In 2009, it was determined that a commercial field in Jeff Davis County became infected with
Asian soybean rust earlier than believed likely based upon an intensive scouting program across the
Timely fungicide application
state. The Cooperative Extension agent in Jeff Davis County used this example to provide education to
growers, agents, consultants, and industry representatives in the region and to help refine
recommendations in Georgia for the timing of applications of fungicides to protect against this disease.
Acknowledgements:
Special thanks to Jeff Davis County farmer Mr Alton Walters for allowing us to conduct this soybean rust
farmer, Mr.
field day on his property.
Timely fungicide
application
Soybean field where Asian soybean Comparison of soybean fields with timely
rust was found in Jeff Davis County fungicide application and late fungicide application