You'll hear gardeners and growers all over Michigan asking that question as they discover dark and nasty-looking lesions on tomato plants and tomatoes.
Turns out, Michigan's tomatoes are catching the very same disease that wiped out the Irish potato crop in the 1840s to catastrophic result. It's called "late blight".
Mary Hausbeck is a professor in the plant pathology department at Michigan State University. Hausbeck says late blight is caused by a microorganism that enjoys cool, wet conditions, and this is exactly the type of weather we’ve had this year.
If we want to use fungicides to protect the plants, Hausbeck recommends using products that list chlorothalonil as the active ingredient and applying at least every seven days.
*Listen to the interview with Mary Hausbeck above.