Soybean Disease Loss Estimates From the United States and Ontario, Canada — 2021

Each year, soybean diseases reduce yield in the United States and Ontario, Canada. The importance of these diseases varies annually, and many factors generally influence which diseases significantly affect yield. These factors can include environment, production practices, and a variety’s susceptibility to disease.

The current publication provides the estimated annual soybean yield losses as a result of plant diseases during the 2021 season for the major soybean-producing areas in the United States and Ontario, Canada. Extension, university, USDA plant pathologists, and soybean specialists from each state and province provided the estimates. These reports accounted for 99.9 percent of the total soybean production in the United States and Ontario in 2021. The estimated losses include those caused by foliar diseases, stem diseases, nematodes, seedling blights, and diseases of harvested grain.

Disease loss estimates are gathered using several different methods which most typically include disease surveys; interactions with Extension, university, government, industry, and farmer representatives; and personal experience with disease losses. Estimation methods vary by state or province.

For the current publication, the authors determined disease loss values based on yield before estimated losses for each state or province using this formula:

(harvested bushels/[{100 – percent estimated disease loss}/100])

The authors then formulated the total number of bushels lost for each disease ([percent loss/100] x yield before estimated loss) for each state or province.

Additional information on yield and economic losses due to soybean diseases can be found at the CPN Field Crop Disease Loss Calculator. 

2021 Production

The United States produced more than 4.4 billion bushels of soybean in 2021, an increase of more than 0.3 billion bushels as compared to 2020. Ontario, Canada, produced 150 million bushels in 2021.

2021 Disease Losses

In all, 5.8 percent of the potential estimated soybean production (bushels/acre) in 2021 were lost due to disease in the 29 soybean-producing states, and 7.0 percent of the total estimated soybean bushels in 2021 were lost due to disease in Ontario, Canada. Table 1 provides yield loss estimates for the specific diseases included in the survey of plant pathologists throughout the soybean production system in the U.S. and Ontario, Canada. Estimated percent losses in 2021 were slightly more than those reported in 2020, but less than those reported during either 2018 or 2019.

Table 1. Estimated soybean yield losses from diseases in 29 soybean producing states in the United States and Ontario, Canada in 2021, listed in order of most losses to least losses in each disease category.

¹Lance, root lesion, spiral, sting, and stubby root. Only root lesion nematode was reported in Ontario, Canada; ²A portion of the estimated yield loss value for purple seed stain in the U.S. is due to dockage from low quality seed reported from New York; ³Bean pod mottle, soybean mosaic, soybean vein necrosis, tobacco ringspot, and tobacco streak. Only soybean mosaic was reported in Ontario, Canada; ⁴A portion of the estimated yield loss value for Diaporthe (Phomopsis) seed decay in the U.S. is due to dockage from low quality seed reported from New York. The estimated yield loss value for Diaporthe (Phomopsis) seed decay from Ontario is due to dockage from low quality seed; ⁵Phymatotrichum root rot and a possible viral disease.

Diseases in the Northern United States

The northern states in the U.S., which included Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Dakota, and Wisconsin, accounted for 72.0 percent of the total estimated U.S. yield losses in 2021. Because more than three-quarters of U.S. soybean production occurs in the northern states, disease losses in these states greatly affect the overall importance of different diseases across the country (see Table 2). However, dry conditions in soybean production areas in 2021, as well as in 2020, likely resulted in less disease loss than has previously been observed to occur in the northern region. There were no foliar diseases among the top yield-reducing diseases in 2021 in the northern region.

Table 2. Estimated soybean yield losses due to the seven most significant diseases in the northernmost U.S. states¹ in 2021.

¹Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Dakota, and Wisconsin.

Diseases in the Southern United States

Soybean cyst nematode, root-knot nematode, and seedling diseases caused the most estimated yield losses in 2021 in the southernmost U.S., which included Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia (see Table 3).

Table 3. Estimated soybean yield losses due to the seven most significant diseases in the southernmost U.S. states¹ in 2021.

¹Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia.

Diseases in Ontario, Canada

Soybean cyst nematode caused the greatest estimated yield loss in Ontario, Canada, in 2021, followed by sudden death syndrome and seedling diseases (see Table 4). Septoria brown spot was the only foliar disease present among the top yield-reducing diseases in Ontario.

Table 4. Estimated soybean yield losses due to the seven most significant diseases in Ontario, Canada in 2021.

¹The estimated yield loss value for Diaporthe (Phomopsis) seed decay from Ontario is due to dockage from low quality seed.

Disclaimer

The yield losses estimated in this publication were provided by members of the North Central Research and Extension Activity (NCERA) 137 Soybean Disease Committee and the Southern Soybean Disease Workers. The information contained in the current publication is meant to be used as a guide. The values in this publication are estimates and are not intended to be used as exact measurements of soybean yield losses due to plant diseases. However, these data provide valuable insight into the ranking of importance of a given disease within a production region (north or south) as well as across the entire production system. The most appropriate means available were used to estimate disease losses and no liability resulting from the use of these estimates is assumed.

Additional information on yield and economic losses due to soybean diseases can be found at the CPN Field Crop Disease Loss Calculator. 

Acknowledgments

Authors

Carl Bradley, University of Kentucky; Tom Allen, Mississippi State University; Daren Mueller, Iowa State University; Albert Tenuta, Ontario Ministry of Agriculture, Food and Rural Affairs; Kelsey Mehl, University of Kentucky; and Adam Sisson, Iowa State University 

Contributors

Ed Sikora, Auburn University; Terry Spurlock and Travis Faske, University of Arkansas; Alyssa Koehler, University of Delaware; Nick Dufault and Ian Small, University of Florida; Bob Kemerait, University of Georgia; Chelsea Harbach, University of Illinois; Darcy Telenko and John Bonkowski, Purdue University; Daren Mueller, Iowa State University; Rodrigo Onofre, Kansas State University; Carl Bradley, University of Kentucky; Trey Price and Boyd Padgett, Louisiana State University; Marty Chilvers and Fred Warner, Michigan State University; Dean Malvick, University of Minnesota; Tom Allen, Mississippi State University; Kaitlyn Bissonnette, University of Missouri; Tamra Jackson-Ziems, University of Nebraska; Gary Bergstrom, Erik Smith, and Ken Wise, Cornell University; Rachel Vann, North Carolina State University; Samuel Markell, North Dakota State University; Horacio Lopez-Nicora, The Ohio State University; Josh Lofton, Oklahoma State University; Albert Tenuta, Ontario Ministry of Agriculture, Food and Rural Affairs; Alyssa Collins and Paul Esker, Pennsylvania State University; John Mueller, Clemson University; Febina Mathew, Emmanuel Byamukama, and Connie Tande, South Dakota State University; Heather Kelly, University of Tennessee; Tom Isakeit, Texas A&M University; David Langston, Virginia Tech; and Damon Smith, University of Wisconsin-Madison. 

Images

Figure 2 by Adam Sisson, Iowa State University and Figure 3 by Carl Bradley, University of Kentucky.

Sponsors

The authors thank the United Soybean Board and the Grain Farmers of Ontario for their support. Support also was provided by State and Federal Funds appropriated to the State Land Grant Institutions of cooperating authors and the United States Department of Agriculture - National Institute of Food and Agriculture (USDA-NIFA).