Wheat Disease Loss Estimates from the United States and Canada — 2024

Wheat diseases annually reduce yield in the United States and Canada. Diseases of importance vary by year, and diseases that affect yield are based on multiple factors, including environmental conditions, crop production practices, and susceptibility of a given variety to disease.

Plant pathologists representing 29 wheat-producing U.S. states and two Canadian provinces estimated the percent yield losses from wheat disease in their state or province. These reports account for 88.8 percent (1.75 billion bushels) of the total wheat produced in the United States and 35.6 percent (458 million bushels) of the total wheat produced in Canada in 2024 (Figure 1). The yield loss estimates include root, stem, foliar, head, and kernel diseases in the states/provinces represented in this survey. Additional information on yield and economic losses due to wheat diseases can be accessed at the CPN Field Crop Disease and Insect Loss Calculator. 

This publication documents the impact of major diseases on wheat production during 2024. The North Central Regional Committee on Management of Small Grain Diseases (NCERA 184) and the Western Wheat Workers (WERA 97) revise the wheat disease loss estimates annually. It is important to note that methods for estimating disease loss vary by state or province. The estimates may be based on statewide disease surveys; feedback from university Extension, industry, farmer representatives; and personal experience with disease losses.

Determination of disease loss values is based on yield prior to estimated losses for each state or province using the formula (harvested bushels/[{100 – percent estimated disease loss}/100]). Total bushels lost per disease is determined for each state or province using the formula ([percent loss/100] x yield before estimated loss). This does not include mycotoxin, black point, or black sooty mold contamination or seed lots contaminated by ergot as these reduce grain quality rather than quantity.

2024 Conditions and Production

Farmers in the United States and Canada planted wheat on 72.9 million acres in 2024. This produced nearly 3.3 billion bushels of wheat, worth $18.1 billion USD. Above average temperatures were observed in the contiguous U.S. in 2024, resulting in the warmest year on record. Multiple states experienced drought while others experienced above average precipitation. Several severe weather events, such as hurricane-related winds, may have played a role in the distribution of diseases that can spread long distances via wind such as rusts.

2024 Disease Losses

In 2024, disease reduced harvested wheat bushels by 8.3 percent across the U.S. states included in this survey and by 27.0 percent in Alberta and Ontario. Table 1 provides yield loss estimates for all diseases and Figure 3 presents the proportion of losses by disease or disease group. Total estimated yield losses from wheat disease in the U.S. and in the Canadian provinces of Alberta and Ontario was 326.7 million bushels, which was valued at $1.8 billion USD. This does not include the economic costs of disease management practices such as fungicide seed treatment or foliar fungicide application, crop scouting, or development of disease-resistant varieties. 

Table 1. Estimated wheat yield losses from diseases in 29 wheat-producing states in the United States and two provinces in Canada in 2024.

¹Can include needle, root-gall, root-knot, stem and bulb, stubby-root, and stunt nematodes; ²Can include Alternaria leaf blight, anthracnose, Ascochyta leaf spot, bacterial mosaic, and downy mildew; ³Can include pink snow mold, speckled snow mold, and snow rot; ⁴Can include Agropyron mosaic and Brome mosaic.

Disease Losses by Region

To increase the granularity of loss data, wheat-producing states were divided into six regions (Figure 4) and the top five yield-limiting diseases for each region are reported in Tables 2-7.

East North Central U.S. States and Ontario, Canada

This region represents 14.0 percent of the wheat produced in the U.S. and in Alberta and Ontario, Canada and consists of Illinois, Indiana, Kentucky, Michigan, Missouri, New York, Ohio, Ontario, and Wisconsin. Total losses to plant disease were estimated to be 10.5 million bushels, or 3.0 percent of production in this region.

Table 2. Estimated wheat yield losses due to the five most significant diseases in the U.S. East North Central states¹ and Ontario, Canada in 2024.

¹Illinois, Indiana, Kentucky, Michigan, Missouri, New York, Ohio, and Wisconsin.

Mid-Atlantic U.S. States

This region represents 2.3 percent of the wheat produced in the U.S. and in Alberta and Ontario, Canada and consists of Delaware, Maryland, North Carolina, Pennsylvania, and Virginia. Total losses to plant disease were estimated to be 2.2 million bushels, or 3.8 percent of production in this region.

Table 3. Estimated wheat yield losses due to the five most significant diseases in the U.S. Mid-Atlantic states¹ in 2024.

¹Delaware, Maryland, North Carolina, Pennsylvania, and Virginia.

Mountain West U.S. States

This region represents 28.9 percent of the wheat produced in the U.S. and in Alberta and Ontario, Canada and consists of Alberta, Colorado, Idaho, and Montana. Total losses to plant disease were estimated to be 200.8 million bushels, or 22.2 percent of production in this region.

Table 4. Estimated wheat yield losses due to the five most significant diseases in U.S. Mountain West states¹ and Alberta, Canada in 2024.

¹Colorado, Idaho, and Montana.

Southeast U.S. States

This region represents 1.6 percent of the wheat produced in the U.S. and in Alberta and Ontario, Canada and consists of Alabama, Arkansas, Georgia, Louisiana, Mississippi, and Tennessee. Total losses to plant disease were estimated to be 0.8 million bushels, or 2.0 percent of production in this region.

Table 5. Estimated wheat yield losses due to the five most significant diseases in the U.S. Southeast states¹ in 2024.

¹Alabama, Arkansas, Georgia, Louisiana, Mississippi, and Tennessee.

Northern Great Plains U.S. States

This region represents 21.7 percent of the wheat produced in the U.S. and in Alberta and Ontario, Canada and consists of Minnesota, North Dakota, and South Dakota. Total losses to plant disease were estimated to be 53.8 million bushels, or 9.3 percent of production in this region.

Table 6. Estimated wheat yield losses due to the five most significant diseases in the U.S. Northern Great Plains states¹ in 2024.

¹Minnesota, North Dakota, and South Dakota.

Southern Great Plains U.S. States

This region represents 22.4 percent of the wheat produced in the U.S., and in Alberta and Ontario, Canada and consists of Kansas, Nebraska, Oklahoma, and Texas. Total losses to plant disease were estimated to be 58.4 million bushels, or 9.7 percent of production in this region.

Table 7. Estimated wheat yield losses due to the five most significant diseases in the U.S. Southern Plains states¹ in 2024.

¹Kansas, Nebraska, Oklahoma, and Texas.

Disclaimer

The disease loss estimates in this publication were provided by members of the North Central Regional Committee on Management of Small Grain Diseases (NCERA 184) and the Western Wheat Workers (WERA 97). This information is only a guide. The values in this publication are not intended to be exact estimates of wheat yield losses due to diseases. The members of NCERA 184 used the most appropriate means available to estimate disease losses and assume no liability resulting from the use of these estimates.

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 and Insect Loss Calculator at https://loss.cropprotectionnetwork.org/.

Acknowledgements

Authors

Nolan Anderson, Texas A&M University; Adam Sisson, Iowa State University; Kelly Turkington, Agriculture and Agri-Food Canada; Kira Bowen, Auburn University; Travis Faske, University of Arkansas; Ron Meyer, Colorado State University; Alyssa Betts, University of Delaware; Alfredo Martinez Espinoza, University of Georgia; Juliet Marshall, University of Idaho; Boris X. Camiletti, University of Illinois Urbana-Champaign; Darcy Telenko, Purdue University; Kelsey Anderson-Onofre, Kansas State University; Carl Bradley, University of Kentucky;  Paul “Trey” Price III, Louisiana State University; Martin Chilvers, Michigan State University; Jochum Wiersma, University of Minnesota; Tom Allen, Mississippi State University; Mandy Bish, University of Missouri; Uta McKelvy, Montana State University; Stephen Wegulo, University of Nebraska-Lincoln; Gary Bergstrom, Cornell University; Christina Cowger, USDA-ARS Raleigh, North Carolina; Andrew Friskop; North Dakota State University; Pierce Paul, Ohio State University; Meriem Aoun, Oklahoma State University; Albert Tenuta, Ontario Ministry of Agriculture, Food, and Rural Affairs; Alyssa Collins, Pennsylvania State University; Madalyn Shires, South Dakota State University; Heather Kelly, University of Tennessee; Ken Obasa, Texas A&M University; David Langston and Doug Higgins, Virginia Tech; and Damon Smith, University of Wisconsin-Madison.

Reviewers

Daren Mueller, Iowa State University and Kiersten Wise, University of Kentucky.

Production data from the United States Department of Agriculture-National Agricultural Statistics Service and the Statistics Canada. Climate information from the National Oceanic and Atmospheric Administration-National Center for Environmental Information.

United States Department of Agriculture National Agricultural Statistics Service. Quick Stats Database. Accessed 10-12 March 2025.

Statistics Canada. Table 32-10-0359-01 Estimated areas, yield, production, average farm price and total farm value of principal field crops, in metric and imperial units. Accessed 10-12 March 2025.

In addition to support from the United States Department of Agriculture - National Institute of Food and Agriculture, this project was funded in part through the Grain Farmers of Ontario, the Alberta Agriculture and Irrigation, and Agriculture and Agri-Food Canada.