New survey spotlights concern about tar spot

As tar spot spreads across the Midwest, a new survey confirms the disease is top of mind for many farmers. In a survey commissioned by AgReliant Genetics, more than half of the farmers surveyed cited tar spot as a potential disease when asked about what diseases may impact corn in their area. One-third of the respondents named tar spot first.

“AgReliant Genetics is dedicated to bringing tools and information farmers need to manage diseases like tar spot,” said Christy Toedebusch, vice president of product management, marketing and digital at AgReliant Genetics, in a news release. “We are sharing these survey results to help the industry gain a better understanding of farmers’ pain points when it comes to tar spot.”

• READ MORE: Agronomy Tip: Put tar spot disease on your radar

While dry conditions limited tar spot impact in 2022, 71% of surveyed farmers expressed heightened concern, primarily due to the disease's rapid spread. More than half the respondents had detected tar spot on their land at least once, with 90% of those experiencing yield loss. 

Management knowledge gap

Tar spot concern eclipses worry about other diseases, especially in states where tar spot is prevalent. In the survey, 56% of farmers in high risk states indicated they are very or extremely concerned about tar spot. 

• READ MORE: Arrival of tar spot alters plans

While concern is high, farmers lack clear direction on how to manage the disease. A third of respondents understand tar spot’s yield impact, only 16% said they understand how it overwinters and 17% understand how it spreads or under what conditions. Farmers also lacked understanding of fungicide efficacy on tar spot.

“We had a major outbreak in 2021. In 2022, we applied fungicide, but there was practically no incidence of this disease in our area. Now we are unsure if it’s necessary to spray,” commented one farmer. 

Utilizing tolerant hybrids 

Farmers plan to use a combination of management practices including crop rotations, field scouting, and planting hybrids with high tar spot tolerance scores. Notably, 71% of farmers plan to plant hybrids with high tar spot tolerance scores in 2023 – a 24-point increase over the percentage currently using tolerant hybrids.

• READ MORE: 5 tips for identifying tar spot disease

While farmers are aware of tar spot tolerance in hybrids, the survey found as few as one in three farmers know about their seed brand’s offerings. Despite this, 55% of farmers agreed they can diversify genetics to mitigate risk. 

“Genetic diversity provides critical protection against the weather and disease threats, tar spot included,” said Mike Kavanaugh, director of product development at AgReliant Genetics, in a news release. “When you plant a diverse array of hybrids that may respond differently to different weather or disease challenges, you spread your risk. Tar spot is an opportunistic disease that attacks weaker plants, which is why it’s so important to make diverse genetics a part of any tar spot management strategy.”