Soybean Disease Loss Estimates From the United States and Ontario, Canada — 2020

Soybean Disease Loss Estimates From the United States and Ontario, Canada — 2020

CPN-1018-20. Published June 1, 2021. DOI: doi.org/10.31274/cpn-20210607-2

 

Each year, soybean diseases reduce yield in the United States and Ontario, Canada. The importance of these diseases varies annually, and many factors 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 due to plant diseases and pathogens in 2020 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 2020. The estimated losses include those caused by foliar diseases, stem diseases, nematodes, seedling blights, and diseases of harvested grain.

Disease loss estimates are gathered through various means including 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 this 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.

2020 Production

The United States produced more than 4.1 billion bushels of soybean in 2020, an increase of nearly 0.6 billion bushels from 2019. Ontario, Canada, produced 143.6 million bushels in 2020.

Figure 1. 2020 soybean production (in millions of bushels) from 29 U.S. states and Ontario, Canada. 

Figure 2. Seedling diseases, such as those caused by Pythium species (shown here), were estimated to have caused more than 22 million bushels of yield losses in 2020 in the United States and Ontario.

Image: Marty Chilvers

2020 Disease Losses

In all, 5.0 percent of the potential estimated soybean production (bushels/acre) in 2020 was lost due to disease in the top 29 soybean-producing states, and 9.1 percent of the total estimated soybean production in 2020 was 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 2020 were less than those reported during either of the preceding two years.

Table 1. Estimated soybean yield losses from diseases in 29 soybean producing states in the United States and Ontario, Canada in 2020, listed in order of most losses to least losses in each disease category.

Disease Total US losses (thousands of bushels) Total Ontario losses (thousands of bushels)
Root Rots and Seedling Blights
Soybean cyst nematode 87,353 5,529
Seedling diseases due to Fusarium, Pythium, Phomopsis, and Rhizoctonia 22,065 2,369
Root-knot nematode 10,398 0
Taproot decline 1,941 0
Reniform nematode 1,550 0
Other nematodes¹  1,129 79
Leaf and Aboveground Diseases
Cercospora leaf blight 7,599 16
Frogeye leaf spot 6,612 16
Septoria brown spot 5,563 158
Soybean rust 1,628 0
Purple seed stain² 1,323 16
Rhizoctonia aerial blight 1,162 0
Target spot 708 0
Virus diseases³ 443 2
Bacterial diseases 114 16
Downy mildew 98 0
Stem Diseases
Sudden death syndrome 20,055 3,159
Phytophthora root and stem rot 16,701 1,975
Charcoal rot 8,623 32
Sclerotinia stem rot (White mold) 7,885 395
Pod and stem blight 5,226 16
Stem canker 3,040 158
Southern blight 1,969 0
Diaporthe (Phomopsis) seed decay4 1,851 158
Brown stem rot 1,315 79
Anthracnose 968 16
Fusarium wilt and root rot 341 158
Other Diseases
Other diseases5 12 0

¹Lance, root lesion, 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 North Carolina and New York. The estimated yield loss value for Diaporthe (Phomopsis) seed decay from Ontario is due to dockage from low quality seed; 5Phymatotrichopsis root rot and red crown rot

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 66.0 percent of the total estimated yield losses in 2020. Because 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, drought conditions in soybean production areas in 2020 likely resulted in less disease loss than is normal in the northern region.

Table 2. Estimated soybean yield losses due to the seven most significant diseases in the northernmost U.S. states¹ in 2020.

Rank Disease/Pathogen Total losses (thousands of bushels)
Northern Region Nation
1 1 Soybean cyst nematode 70,403
2 2 Seedling diseases due to Fusarium, Pythium, Phomopsis, and Rhizoctonia 15,335
3 3 Sudden death syndrome 14,551
4 4 Phytophthora root and stem rot 12,414
5 7 Sclerotinia stem rot (White mold) 7,884
6 6 Charcoal rot 7,439
7 9 Frogeye leaf spot 4,427

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

Figure 3. Frogeye leaf spot was the only foliar disease among the top yield-reducing diseases in the northern U.S. in 2020.

Image: Carl Bradley

Diseases in the Southern United States

Soybean cyst nematode, root-knot nematode, and Cercospora leaf blight were the three diseases of greatest importance in 2020 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 2020.

Rank Disease/Pathogen Total losses (thousands of bushels)
Southern Region Nation
1 1 Soybean cyst nematode 16,950
2 5 Root-knot nematode 10,358
3 8 Cercospora leaf blight 7,551
4 2 Seedling diseases due to Fusarium, Pythium, Phomopsis, and Rhizoctonia 6,730
5 3 Sudden death syndrome 5,504
6 4 Phytophthora root and stem rot 4,287
7 10 Septoria brown spot 2,958

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

Diseases in Ontario, Canada

Similar to 2019, soybean cyst nematode caused the greatest estimated yield loss in Ontario, Canada, in 2020, followed by sudden death syndrome and seedling diseases (see Table 4). There were no foliar diseases 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 2020.

Rank Disease/Pathogen Total losses (thousands of bushels)
Ontario, Canada United States
1 1 Soybean cyst nematode 5,529
2 3 Sudden death syndrome 3,159
3 2 Seedling diseases due to Fusarium, Pythium, Phomopsis, and Rhizoctonia 2,369
4 4 Phytophthora root and stem rot 1,975
5 7 Sclerotinia stem rot (White mold) 395
6a 15 Diaporthe (Phomopsis) seed decay 158
6b 25 Fusarium wilt and root rot 158

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.

Values reported in this document were accurate as of publication date and do not reflect corrections or updates occurring since that time. For the most up-to-date values and additional information on yield and economic losses due to diseases, see the Field Crop Disease Loss Calculator at https://loss.cropprotectionnetwork.org/.

Acknowledgments

Authors

Carl Bradley, University of Kentucky; Tom Allen, Mississippi 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, University of Florida; Bob Kemerait, University of Georgia; Nathan Kleczewski, University of Illinois; Darcy Telenko, 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 and James Kurle, University of Minnesota; Tom Allen, Mississippi State University; Kaitlyn Bissonnette, University of Missouri; Tamra Jackson-Ziems, University of Nebraska; Gary Bergstrom, Cornell University; Lindsey Thiessen, North Carolina State University; Samuel Markell and Berlin Nelson, North Dakota State University; Anne Dorrance, The Ohio State University; John Damicone, 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; Emmanuel Byamukama and Connie Tande, South Dakota State University; Heather Kelly, University of Tennessee; Tom Isakeit, Texas A&M University; Hillary Mehl, Virginia Tech; and Damon Smith, University of Wisconsin-Madison.

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).

 

This publication was developed by the Crop Protection Network, a multi-state and international collaboration of university/provincial extension specialists and public/ private professionals that provides unbiased, research-based information to farmers and agricultural personnel.

This information in this publication is only a guide, and the authors assume no liability for practices implemented based on this information. Reference to products in this publication is not intended to be an endorsement to the exclusion of others that may be similar. Individuals using such products assume responsibility for their use in accordance with current directions of the manufacturer.

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Soybean Disease Loss Estimates From the United States and Ontario, Canada — 2020

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