The scourge known as late blight

North Country Gardening

Anyone who grew tomatoes and potatoes in 2009 remembers how devastating late blight can be to your garden. Since then, we’ve kept a closer watch on this disease to proactively protect our gardens.

Over the summer, confirmed infestations of late blight have crept closer and closer to the North Country. Unfortunately, it has been confirmed in the Plattsburgh area recently.

Just a few weeks ago, late blight had been confirmed as close as Vermont and the Albany area. Then, Hurricane Irene came bringing with her wind, rain, flooding, and late blight spores. Luckily, it is at the end of the season and with some protection, you can still enjoy a bountiful harvest.

Late blight looks like black/brown lesions on the leaves, stems, and fruit of the plant. The lesions can look fuzzy during cool, moist conditions. The fungus spreads quickly within the plant, causing the plant to die within days.

Since potatoes are pretty close to being finished, the best line of defense for this crop is to harvest the tubers. First cut all the tops off of the plants. Leave the tubers in the ground for several days to cure, dig, and enjoy your spuds!

Cutting the tops of the plants off and allowing the tubers to cure are important steps in the potato harvest you don’t want to skip. Late blight needs living tissue to survive. Removing the tops of the plants reduces the chances of having the tubers become infected. Curing the tubers, allows for the skins to toughen. This prevents damage to the tubers during the harvesting process, reducing the chances of infection.

With the cool wet spring we had, our tomatoes got off to a late start so there are still plenty ripening on our vines. One way to save your crop is to bring any tomatoes inside that are showing any color at all. Place the tomatoes in a sunny kitchen window and they will ripen.

If you feel the need to spray your garden start now before there are any late blight symptoms. Home gardeners can use copper or chlorothalonil. If you do choose to spray, follow the instructions and pay close attention to the waiting period between spraying and harvesting.

If you suspect a late blight infection, take a sample to your local Cornell Cooperative Extension. They can diagnose the issue and provide you with further instructions on how to properly dispose of your plants. Proper disposal is vital if we want to prevent the spread of late blight to other gardens.

Anne Lenox Barlow is a professional horticulturist who enjoys gardening with her family in Plattsburgh. She also chronicles her gardening experiences at her blog www.northcountrygarden.wordpress.com. She can be reached at a.lenox.barlow@gmail.com.

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