frogeye leaf spot of soybean

The Crop Protection Network recently launched its new “Field Crop Disease Loss Calculator” research tool, complete with years of historical data for estimated losses caused by disease in corn and soybeans in the U.S. and Ontario, Canada.

The calculator sources annual disease loss estimates from university experts, coupled with data from the USDA National Agricultural Statistics Service, and can be sorted by state, U.S. region, crop and disease, according to an Iowa State University news release.

The calculator interface was designed to provide easier access to and dissemination of estimated disease loss data to researchers, educators and policy makers. The estimate outputs from the calculator help provide a snapshot of disease severity in regards to economic impacts over time, which can help to inform research needs to prevent economic damage.

Such an example includes the disease frogeye leaf spot of soybean. This disease caused an average yearly loss of approximately 460,000 bushels from the years 1996-2000 in Midwestern states, while average yearly losses from 2013-17 were approximately 7.6 million bushels in those same states.

“University researchers, Extension specialists and educators have often expressed a need for accurate disease loss estimates across multiple states in the U.S. for grant writing and policy purposes,” said CPN Executive Committee Director and Iowa State University plant pathologist Daren Mueller. “This calculator provides them and the rest of the plant pathology community with a tool to write better proposals and communicate policy more effectively to further the mission of protecting U.S. crops.”

Every year, land grant university Extension plant pathologists and researchers from the Corn Disease Working Group, North Central Research and Extension Activity (NCERA): 137 Soybean Disease Committee and the Southern Soybean Disease Workers review and revise disease loss estimates, based on data gathered from in-state surveys and from USDA reports. Based on the received data, researchers calculate loss estimates based on production prior to estimated losses for each state.

Average loss values are measured in U.S. dollars, and are determined by dividing economic losses by acres planted. Currently, the calculator provides data on corn (from 2012-16) and soybean (from 1996-2017).

Visit, or access the calculator from the “Resources” tab at This tool is free and available to all. It will be maintained as disease loss estimates are calculated annually.