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

By Nolan Anderson and Adam Sisson et.al

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.