Sep 15, 2022

Late blight monitoring, cautionary practices encouraged in Midwest

Several cases of late blight have been confirmed in Michigan in recent weeks, and researchers in the Midwest are suggesting preventative measures and close monitoring.

Late blight, a foliar disease that attacks potato and tomato plants, was confirmed in small areas of six potato fields in West Michigan in early September, according to an email announcement by Michigan State University Associate Professor Jaime Wilbur, a member of MSU’s potato and sugar beet pathology program.

The affected potato fields were immediately vine-killed and other “immediate measures have been taken to reduce further spread,” Wilbur said. However, recent weather conditions have been favorable to late blight, so “preventative foliar programs and diligent crop monitoring is strongly recommended,” she added.

Michigan State’s late blight forecast tool can be found here. MSU also has information on recommended fungicide rates.

Late blight has not been detected in any neighboring states to Michigan, however, conditions are favorable in the region.

University of Wisconsin (UW) Professor and Extension Specialist Amanda Gevens encouraged growers in her state via email to use foliage protection and closely monitor their fields for late blight. The UW Plant Disease Diagnostics Clinic is available to assist Wisconsin growers with late blight detection at no cost.

More information on potato late blight can be found at Gevens’ laboratory website, as well as on tomato late blight.