Tomato Blight Panic In Pennsylvania

Tomato blight struck Pennsylvania in 2009 and the results were catastrophic for farmers and gardeners alike, as the fungus wiped out the majority of the tomato crop.

The blight epidemic sent gardeners into a panic, radically pruning infected leaves and removing infected fruit from blighted plants as quickly as possible. Personally, I could hardly keep up with it and managed to save only a small amount of my tomatoes.

What is Tomato Blight?

Tomato blight, more specifically early blight, and late blight, are fungi that thrive in wet conditions. In 2009, my area of Pennsylvania, the Lehigh Valley, didn’t see a 90+ degree day until mid-August (very, very late) and June and July were literally a wash: June’s rainfall was nearly three inches above normal and July’s was more than 1.6 inches above normal. Average temperatures hovered well below their normal range for the entire season.

These weather conditions created a “perfect storm” for tomato blight and other fungi which spread like mad. One local organic farmer told me that his entire field of heirloom tomatoes was wiped out – he had to destroy them all. A popular rumor as to the source of the infection was that one grower who supplied plants to big box stores was responsible, which seems to be validated in some of the following articles:

• Washington Post: Tomato Blight Hits Some Farmers, Spares Others
• Morning Call (Allentown) Penn State Master Gardeners Blog: Late Blight Confirmed in Five Pennsylvania Counties
• The Post-Gazette (Pittsburgh): Tomato crops hit by late blight

What to do if you discover Tomato Blight

If you’re unlucky enough to find that blight has struck your tomatoes, do not compost any blighted fruit, leaves or stems and do not save the seeds. Bag or burn fruit, stems and foliage to avoid carrying the infection over to next season.

One last thought: all of my infected plants were in my raised beds, where I planted seedlings of various types (bought from a nursery). However, the “volunteer” plants that sprang up in my flower beds from composted tomato seeds showed little to no sign of infection. Fortunately, I just let them grow where they popped up, or I would have had even fewer tomatoes.  The closest “volunteer” to my raised beds was about 20 feet, which showed some symptoms, but the volunteers that grew 30 feet or more away from the blighted plants showed no signs of tomato blight at all.