The findings will help growers in the U.S. understand how foliar fungicides — applied to leaves — fit into overall soybean production practices, noted Paul Esker, associate professor of epidemiology and field crop pathology in the College of Agricultural Sciences, who collaborated with Denis Shah, associate scientist in the Department of Plant Pathology, Kansas State University.
Soybean is one of the major crops produced in the U.S., planted on an estimated 87.6 million acres in 2020. Esker explained that success in growing soybean depends on multiple management decisions, including choice of cultivar, sowing date, seeding rate, nutrient fertilization, irrigation, drainage, crop rotation and tillage.
Foliar fungicides — used to prevent fungal plant diseases such as frogeye leaf spot and brown spot — are another management consideration. These diseases can flourish when temperatures are warm with humid conditions, such as those that occur in regions known for producing soybean. These fungal diseases have the potential to impact crop health and yield.
Previous field trials have demonstrated that when there is little or no disease present, there is no economic benefit to using foliar fungicides, Shah and Esker explained. Despite that information, the use of foliar fungicides in U.S. soybean production almost tripled from 2005 to 2015.