Identifying late blight on tomato plants
Late blight is devastating Northeast tomato crops. How can you tell if your plants are infected?
Photo: photofarmer/Flickr Lesions develop on leaves and stems as dark, water-soaked spots. These spots enlarge until the entire leaf or stem turns brown and dies. Dead leaves typically remain attached to stems. The undersides of the lesions may be covered with a white fuzzy growth that contains the spores of the pathogen. On the stems, late blight lesions appear brown to almost black. Infected tomato fruits develop shiny, dark or olive-colored lesions which may cover large areas. Potato leaves and stems will show the same symptoms. Infected potato tubers develop a dry, corky rot that often shows up in storage.
They’ve also put together this video to help explain what late blight is, how to identify it, and what to do if your plants get infected.
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Comments
I have to disagree that a plant must be pulled at the first signs of Late Blight. This year I had tomatoes in a pot and tomatoes in the ground, both outdoors. Unfortunately, the pot tomatoes contracted Late Blight before I knew what it was, and have grown too severely infected to be salvaged.
The tomatoes in the ground, on the other hand, had only a few leaves that were infected when I finally learned about Late Blight. If you're able to catch Late Blight early, picking off infected.... More
Here we go again- definite blight on our tomato plants... (Otsego County, NY)
blight is a curse ,came home from work, today, 2 plants covered in brown spots should i just pull them or spray with fungicide .
it is a very severe disease in the world.
not helpful,but kind of fun: http://www.youtube.com/watch?v=lV8UleIKvIA
So my tomatoes made it until September and like others, were the best I have grown in 30 years. Two weeks later and I pulling plants and trying to save any fruit I think might ripen before it rots.
My questions are about cleaning up after the fungus. Do I have to disinfect my soaker hoses? They spend the winter in an unheated garage that goes into the 20's for long periods of time. Do I have to send the infected plants to the dump or can I take them to the back of my three acre lot to.... More
Can you burn the plants? While that stop the spread or make it worse?
I also am a victim of late blight. I grow heirloom varieties that I start from seeds so these are my babies. I have pulled all of my plants and put them in platic garbage bags for pick-up by the local garbage people. But before I pulled all the plants I harvested the green and semi-ripe tomatoes that looked good. After having washed them and drying them carefully, I have laid them out on tables to ripen. I checked each tomatoe carefully for signs of blight. I only saved those w/o blight. .... More
just so you know, plant diseases do not make humans sick. the fungus only affects the plant, its fruit, and the soil its planted in. a secondary organism may have attacked the plant, due to its weakened state. its very possible that the seeds were infected, but the probability of non-infection is greater. i am a plant pathologist living in tennessee, and all of my tomato plants had to be pulled as well. this is after i treated with a copper fungicide & pulled all infected parts. this season.... More
Although I didn't get the blight, 2/3 of my tomato plants never matured because of the heavy rains we had in June in my region. But there really is no one to blame - except Mother Nature (not Mother Nature Network, mind you). I'm sorry you lost all those tomatoes. It's something to have a good cry over.
Perhaps inexperienced gardeners didn't recognize the signs soon enough or plants from big box stores helped to spread it, but in the end, it's the right environmental conditions that spread.... More
I have never had such wondefully strengthy and robust, not to mention HUGE tomato plants in thirty years until this year. Unfortunately, I now have found that they too have the blight as they begin to ripen ... big beautiful tomatoes with absolutely disgusting shiny, almost burn like patches on the fruit.
I will be pulling the fruit green and shelf ripening, along with considerable labor of removing the infected plants - - - what a shame :-(
Thanks MNN for all the insight.
I wrote a piece on this outbreak for my blog a couple of weeks ago. (http://www.basilandbutterflies.com/?p=98 ). The fungus does not hurt humans. So, if your tomatoes look good, you can eat them. You can even cut off some bad spots and eat the rest. That's the good news. The bad news is that you have to pull the plants out of the ground and put them into sealed plastic bags as soon as possible, so the spores don't get.... More
I'm sorry I can't give you a more definite answer. I've searched around and I've seen places that say you can cut the blight out and still eat the tomato and others that say not to. I've got brown spots on some of my tomatoes, but they don't seem to be from late blight and I've been cutting them out and eating the tomatoes. Does anyone out there know for sure if you can eat late blight tomatoes?
I'm seeing signs of late blight on my big beautiful plants loaded with big green (unripe) tomatoes, so I'm ready to yank the plants and dispose of them. My question is this: Can I harvest the green tomatoes to ripen in my window sill or will they get sick and spoil before ripening? The fruits are beautiful right now, only the stems show signs of disease.
