“More bushels per acre” is a claim often touted about a product such as fungicide. Still, that’s just part of the story.

“We often don’t think about what it costs,” says Alison Robertson, Iowa State University Extension plant pathologist.

That’s why Robertson wanted to measure return on investment — in addition to yield in 2023 fungicide trials across six ISU research and demonstration farms.

Meaghan Anderson, ISU Extension field agronomist, assisted Robertson with assigning costs of fungicide application costs that included:

Stressors in these trials included corn rootworm infestations and bacterial leaf streak. However, fungal disease severity that fungicides could have alleviated was low due to drought at all locations.

Fungicides did increase yield, but yield spikes were mainly minimal and did not cover costs.

“If there was ever going to be a year to show that fungicides help with drought stress, this would have been it,” says Robertson. “But they [the applications] didn’t make any money last year.”