Late Blight Watch

Thanks to those big box home improvement stores (you know who, one orange and one blue), those of us in the Northeast have an additional threat to our Potatoes and Tomatoes, late blight. Not familiar with late blight? Ever heard of the Irish Potato Famine? Yep, caused by late blight.

By all accounts it is pretty nefarious stuff, not only does it attack the plant, but it ruins the fruit/tuber as well. It spreads like wildfire too. The only upside is that unlike many other fungi, this one does not live in the soil and, assuming you do not create cull piles of ruined potatoes, should not survive the winter to resurface next spring.

The disease has been spotted all over CT in commercial farms. I'm sure there are many backyard gardeners who are losing their tomatoes (tomato seedlings imported from the south spread the disease initially) and have no idea why. The cool wet weather this summer has been a boon to spreading all sorts of fungi.

Being in a community garden I am quite fearful that we will not escape this disease. I am keeping a close watch on the my plants, so far I believe all I have is some early blight and septoria leaf spot. I am taking an agressive stance on all fungi in my tomatoes. Clipping out any diseased leaves and spraying regularly with Chlorothalonil, which the only fungicide I've found that helps battle this disease. It should be noted that Chlorothalonil does not treat an infection, but will help slow down the spread. Commercial farmers have fungicides available that will treat an infection, however these chemicals are not available to backyard gardeners.

UCONN IPM Info Page

Another info page

Cornell Potato Late Blight Photos

Cornell Tomato Late Blight Photos


Good luck out there!!