New Tools Aim to Catch Corn Tar Spot Early
Research-stage gene and scanner tools could flag the fungal disease about a week before symptoms show, with work expected through 2024.
Updated on Nov. 3, 2026 in Botany
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Insignum AgTech has begun a collaboration with Purdue University researchers on tar spot detection tools for corn. The work is supported by grants from the Indiana Corn Marketing Council and an Innovation Voucher from the state of Indiana. The effort is research-stage, with the collaboration expected to run through the end of 2024.
Why it matters
Tar spot is a fungal disease caused by Phyllachora maydis that can cut corn yields by up to 50% in severe epidemics, and by 2023 it had become the most damaging corn pathogen in the United States. Early detection tools aim to flag infections before farmers can see symptoms, which matters for Indiana, a major corn-producing state.
The approach uses a gene developed from corn plant DNA that causes leaves to form purple spots at infection sites about a week before symptoms appear. Jian Jin's LeafSpec hand-held hyperspectral scanner is being tested to see whether color changes can be detected faster in greenhouse plants.
The players
Insignum AgTech
An agricultural technology company whose work centers on using plant DNA to engineer early-warning gene markers for crop disease.
Purdue University
A public research university in Indiana whose plant science and agricultural engineering researchers are developing tar spot detection algorithms.
Jian Jin
A Purdue researcher who developed the patented LeafSpec hand-held hyperspectral plant leaf scanner.
C.D. Cruz
A Purdue researcher whose team is inoculating Insignum corn with tar spot to test early disease signals.
The details
Insignum AgTech uses DNA already present in corn plants to develop a gene that reveals infection early, causing purple spots at infection sites. C.D. Cruz's Purdue team is inoculating Insignum corn with tar spot to test how plants reveal the disease before symptoms appear. Jin's team will photograph greenhouse plants with the LeafSpec scanner, a patented hyperspectral device that measures light reflected from leaves, to see if color shifts can be detected sooner. Tar spot matters because it reduces a corn plant's ability to absorb sunlight, which lowers yield.
Timeline
2015: Tar spot is first detected in the United States.
2018 and 2021: Early infections cause substantial yield losses.
2023: Tar spot becomes the most damaging corn pathogen in the country.
2024: Insignum's field trials supply drone imagery for the detection algorithms.
End of 2024: The collaboration is expected to conclude.
The Tech Race
The collaboration extends Jian Jin's patented LeafSpec hyperspectral scanner from general plant analysis into early tar spot detection in corn. It places Purdue's sensing work alongside Insignum AgTech's gene-based early-warning approach in the effort to catch the disease before yield losses occur.
The tools remain in research and are not yet available to growers, and no timeline for field use has been announced. Corn producers in Indiana would be the first to benefit if the early-detection approach proves reliable in field conditions.
The takeaway
Watch whether the Insignum and Purdue team reports results showing the purple-spot marker reliably signals tar spot ahead of symptoms in field trials. Results from the collaboration are expected by the end of 2024.
Further reading
For more on the plant science behind this work, explore Botany coverage across Indiana.
Source note: This article includes information reported by Feedstuffs.
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