Soybean Disease Loss Estimates From the United States and Ontario, Canada — 2018

Each year, soybean diseases reduce yield in the United States and Ontario, Canada. The importance of these diseases vary 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 2018 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 used in this publication. These reports accounted for 99.9 percent of the total soybean production in the United States and Ontario in 2018. The estimated losses include those caused by foliar diseases, stem diseases, nematodes, seedling blights, and seed diseases. 

Disease loss estimates are gathered through various means including disease surveys; interactions with extension, university, government, industry, and farmer representatives; and personal experience with diseases 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: bushels harvested/[(100 - percent estimated disease loss)/100]. The authors then formulated total bushels lost per 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. 

2018 Conditions and Production 

The United States produced more than 4.4 billion bushels of soybean in 2018, exceeding totals from 2016 and 2017. Ontario, Canada, produced 154.3 million bushels. 

2018 Disease Losses

In all, 10.6 percent of the total estimated soybean production (bushels/acre) in 2018 were lost due to disease in the top 29 soybean-producing states, and 13.0 percent of the total estimated soybean bushels in 2018 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.

Table 1. Estimated soybean yield losses from diseases in the top 29 soybean producing states in the United States and Ontario, Canada in 2018.

¹ Columbia lance, lesion, sting, and stubby root. Only root lesion nematode was reported in Ontario, Canada.

² Alfalfa mosaic, bean pod mottle, soybean mosaic, soybean vein necrosis, tobacco ringspot, and tobacco streak. Only soybean mosaic was reported in Ontario, Canada.

³ Phymatotrichopsis 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 78.2 percent of the total estimated yield losses in 2018. Since more than three-quarters of U.S. production happens in the northern states, disease losses in these areas greatly affect the overall importance of different diseases across the country (see Table 2). 

Table 2. Estimated soybean yield losses due to the six most significant diseases in the northernmost U.S. states¹ in 2018.

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

Diseases in the Southern United States

Diaporthe/Phomopsis seed decay, soybean cyst nematode, and root-knot nematode were the three diseases of greatest importance in 2018 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. Delayed harvest and wet weather increased the estimated yield reduction due to Phomopsis seed decay in 2018. 

Table 3. Estimated soybean yield losses due to the six most significant diseases in the southernmost U.S. states¹ in 2018.

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

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. This information is only 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. 

Find out More

The Crop Protection Network (CPN) is a multi-state and international collaboration of university and provincial extension specialists, and public and private professionals who provide unbiased, research-based information to farmers and agricultural personnel. Our goal is to communicate relevant information that will help professionals identify and manage field crop diseases. 

Find more crop disease resources at CropProtectionNetwork.org.

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

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

Members of the NCERA-137 Soybean Disease Committee and Southern Soybean Disease Worker groups are university, extension, and government scientists from institutions that include: University of Arkansas, Auburn University, Clemson University, University of Delaware, University of Florida, University of Georgia, University of Illinois, Iowa State University, Kansas State University, University of Kentucky, Louisiana State University, University of Maryland, Michigan State University, University of Minnesota, Mississippi State University, University of Missouri, University of Nebraska, Cornell University, North Carolina State University, North Dakota State University, The Ohio State University, Oklahoma State University, Pennsylvania State University, Purdue University, South Dakota State University, University of Tennessee, Texas A&M University, Virginia Tech, University of Wisconsin-Madison, United States Department of Agriculture – Agricultural Research Service and Ontario Ministry of Agriculture, Food and Rural Affairs.

The following individuals contributed to this publication: 

Ed Sikora, Alabama; Terry Spurlock and Travis Faske, Arkansas; Alyssa Koehler, Delaware; Nick Dufault, Florida; Bob Kemerait, Georgia; Nathan Kleczewski, Illinois; Darcy Telenko, Indiana; Daren Mueller, Iowa; Doug Jardine, Kansas; Carl Bradley, Kentucky; Trey Price and Boyd Padgett, Louisiana; Alyssa Koehler, Maryland; Marty Chilvers and Fred Warner, Michigan; Dean Malvick and James Kurle, Minnesota; Tom Allen, Mississippi; Kaitlyn Bissonnette, Missouri; Loren Giesler, Nebraska; Gary Bergstrom, New York; Lindsey Thiessen, North Carolina; Samuel Markell and Berlin Nelson, North Dakota; Anne Dorrance, Ohio; John Damicone, Oklahoma; Albert Tenuta, Ontario;  Alyssa Collins, Pennsylvania; John Mueller, South Carolina; Emmanuel Byamukama and Connie Tande, South Dakota; Heather Kelly, Tennessee; Tom Isakeit, Texas; Hillary Mehl, Virginia; and Damon Smith, Wisconsin. 

Photos by Carl Bradley and Albert Tenuta. 

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).