We are completing our second crop season since Asian soybean rust (ASR) was found in the United States. We can breathe a sigh of relief and give thanks that ASR did not make its way to Iowa. Indeed, this potentially devastating disease has not plagued the entire north-central United States. Had conditions been favorable for this disease, we were ready to give producers fair warning.
The United States Department of Agriculture (USDA) and the North Central Soybean Research Project (NCSRP) funded the establishment of sentinel plots in Iowa and across the midwestern and southeastern United States. Perhaps you have logged on to www.sbrusa.net to watch the national map that shows the results of scouted sentinel plots and locations where soybean rust has been found. This year's warm, dry weather was not conducive to disease development. Nevertheless, rust was found on soybeans in 25 different counties in seven states: Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, and Texas by September 8.
Rust did not come close to Iowa, but we remained vigilant because this is a new disease and we could not be certain of its progress.
We are sincerely grateful to those who assisted in putting out Iowa's 21 sentinel plots. They are:
|ISU Curtiss Research and Demonstration Farm||Ames|
|ISU Western Research and Demonstration Farm||Castana|
|ISU McNay Research and Demonstration Farm||Chariton|
|ISU Armstrong Research and Demonstration Farm||Crawfordsville|
|ISU Muscatine Island Research and Demonstration Farm||Fruitland|
|ISU Neely-Kinyon Research and Demonstration Farm||Greenfield|
|Croplan Genetics/West Central Cooperative||Jefferson|
|ISU Northern Research and Demonstration Farm||Kanawha|
|ISU Armstrong Research and Demonstration Farm||Lewis|
|ISU Northeast Research and Demonstration Farm||Nashua|
|Croplan Genetics||New Hampton|
|Allee Iowa State University Research and Demonstration Farm||Newell|
|Arnie Shirley and Cornerstone Seeds||Sidney|
|Croplan Genetics||Sioux Center|
|ISU Northwest Research and Demonstration Farm||Sutherland|
|Croplan Genetics||Webster City|
We needed these cooperators to put out the plots, but what made these plots effective was the close monitoring they received throughout the growing season. Trained professionals closely scouted these 21 locations for any signs of rust. We carefully inspected each plot every week. Diseases that were commonly seen in the plots were brown spot, bacterial blight, downy mildew, Cercosopora leaf blight, and frogeye leaf spot. The results of these efforts were regularly posted on the USDA's sbrusa Web site.
Many thanks go to the field crop specialists who added weekly visits to sentinel plots to their already busy schedules. Without their assistance it would have been difficult to scout all the plots. Iowa State University field crop specialists who helped in this regard are Mark Carlton, George Cummins, James Fawcett, John Holmes, Brian Lang, and Virgil Schmidt. Researchers from ISU's Department of Plant Pathology also scouted plots.
We are sincerely grateful to everyone who helped in this important effort.
We also used spore traps to learn whether any spores may have blown into our area.
Iowa's soybeans are no longer at risk for yield loss due to ASR. Nevertheless, researchers continue to monitor spore traps and some late planted long maturity group soybeans to learn whether any spores reach Iowa this fall.
This article originally appeared on pages 236-237 of the IC-496(24) -- September 18, 2006 issue.