Wisconsin Field Crops Disease Update, August 9

Damon Smith, Extension Field Crops Pathologist, Department of Plant Pathology, University of Wisconsin-Madison

Well, it was going to happen sometime soon, tar spot has been confirmed in two counties in Wisconsin. You can track tar spot confirmations in realtime HERE. Both Lafayette and Rock counties were confirmed to have low levels of tar spot in several fields this week. The good news is that these finds are a month behind the initial confirmations in the state for the last two seasons. What does this mean? Well, it means that the tar spot impact on grain yield will likely not be has significant as it has been over the last couple of seasons. Exceptions to this statement will include late-planted corn where the current growth stages are around VT (tasseling) and susceptible silage hybrids. You should scout and track these situations carefully. Be prepared to chop silage early if tar spot really starts to move. You will want to watch moisture carefully in these situations.

Read the rest of the story here: https://badgercropdoc.com/2023/08/09/wisconsin-field-crops-disease-update-august-9-2023/

Tar spot confirmed map from iPipe website