Bayer Crop Science researchers have been able to artificially inoculate tar spot in field test plots, a key step in helping to gain a deeper understanding of how to manage the disease. This development shows promise for advancing both genetic and crop protection research on the pathogen that can severely impact yield. 

“By creating field conditions for tar spot to take place, as well as inoculating the field artificially, we now have a reliable opportunity to study the environment and genetic response to the presence of the disease,” said Christian Heredia, Bayer Crop Science market development manager. “We can rapidly identify and promote new corn hybrids with enhanced tar spot tolerance, as well as enable breeding strategies to deliver more genetic potential.”

Tar spot research in the United States accelerated in 2018 with a widespread epidemic in the Midwest, but it has long been a troubling disease for areas of Latin America. Bayer Crop Science houses a large library of corn germplasm, and the potential to integrate native tar spot tolerance into North America hybrids will be a game-changer for farmers. This ability, combined with the capacity to induce this disease in both the lab and field environments, represents a significant advancement for enhanced screening and identification of tolerant corn germplasm. “The field inoculation is a significant achievement because, although Bayer researchers have previously replicated tar spot in greenhouses, that doesn’t always correlate to what is observed in how a plant will respond in field conditions,” said Heredia.

“Previously, we had to rely on Mother Nature to create the conditions for tar spot,” Jim Donnelly, a DEKALB technical agronomist, noted. “Our field testing allows us to inoculate tar spot wherever we place our plots to help us study and learn more about this potentially devastating disease.”

Increasing tar spot tolerance is one of the numerous focal points of Bayer’s global breeding efforts enabled through precision breeding technology. Bayer’s research and development pipeline — which is the largest in the crop science industry by a 2-to-1 margin — will continue to improve the capacity to characterize products in the coming years and assist in the advancement of commercial launches focused on all aspects of plant health.

“This field inoculation method is a game-changer to deepen our understanding of tar spot,” said Channel technical agronomist Cody Hornaday. “The core practices to managing tar spot still need to be considered: scouting fields, monitoring weather conditions and being ready to apply a fungicide, like Delaro Complete fungicide, if the situation warrants it.”

Protect the Performance

Field inoculation of tar spot is one part of the testing involved with the Bayer Crop Science research and development pipeline — where the company invested more than $2.6 billion in 2022. The testing process is a critical step in speeding up the delivery of future outputs of the pipeline, such as products with increased tar spot tolerance.

As research on tar spot and other diseases progresses, Donnelly said farmers can look forward to new advancements in seed and crop protection technologies that will help to protect the performance of their corn crop.

“Bayer is committed to delivering solutions when it comes to managing and controlling tar spot, both through continued genetic gains and innovations in our fungicide portfolio, to make sure we’re offering farmers multiple options for controlling diseases,” Donnelly said.

Donnelly and Hornaday, as well as other agronomic experts, emphasize that a holistic plan, which includes product selection and placement, scouting, applying fungicides when needed and using general disease management best practices, is necessary to manage tar spot and other diseases successfully.

While research continues on genetic tolerance, farmers can have confidence in continuing to use fungicides with multiple modes of action as effective disease management tools. Bayer’s fungicide portfolio includes Delaro Complete, which offers three modes of action for providing consistent control of major corn and soybean diseases, including tar spot.

To learn more about the tar spot inoculation process, please visit this Bayer Crop Science Facebook post.

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