Tar Spot 7-17-24

Weather events experienced across the Dairyland Seed footprint, especially those caused by Hurricane Beryl, will likely continue the spread of tar spot. Leaf wetness, high humidity and warm temperatures are ideal growing conditions for tar spot. We continue to learn more about how this pathogen infects and spreads through corn.

One observation is that tar spot spores can be transported via wind. This would include the large wind experienced in large weather events like Hurricane Beryl which passed over a large area of the Dairyland Seed footprint.

The time to scout for tar spot is the late vegetative and early reproductive stage. As the corn plant changes from vegetative to reproductive growth, symptoms can become visible. We have many resources on tar spot in past Agronomy Updates. If you have questions about tar spot, please contact your Dairyland Seed dealer, DSM or RA.

Questions regarding tar spot and where we see infection are common throughout the growing season. To better alert folks in areas impacted by tar spot, the Agronomy Team will include a map in the weekly agronomy newsletters showing where tar spot has been confirmed through lab analysis as well as where we have identified suspected tar spot infections.

Counties highlighted in red are areas where tar spot has been confirmed through tissue sample analysis.
Counties highlighted in orange are where Dairyland Seed agronomist have identified tar spot and are waiting for lab analysis to confirm infection.