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Old May 3, 2018   #1
gimmieToms
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Default Blight prevention

Last year for the first time my tomatoes got blight, and I lost the entire crop
It was suggested this year I do some prevention.
What’s the best way I can do this. The more natural the better, but I’m open to what ever works. It was heartbreaking to destroy all my beautiful plants last year. I don’t want to go through that again.
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Old May 3, 2018   #2
carolyn137
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Quote:
Originally Posted by gimmieToms View Post
Last year for the first time my tomatoes got blight, and I lost the entire crop
It was suggested this year I do some prevention.
What’s the best way I can do this. The more natural the better, but I’m open to what ever works. It was heartbreaking to destroy all my beautiful plants last year. I don’t want to go through that again.
Blight is just a general word,it's important to know the specific kind of blight in order to answer your question.

Most blights in Canada affect the foliage as they do where I live as well and the most common ones are

Early Blight, which can appear either early or late in the season, bacterial

Septoria Leaf Spot, fungal.
L
Late Blight, P.infestans is a serious one .

Have you gone to the Disease Forum and looked at the pictures shown there to help make a diagnosis,that might help, especially the ones from Cornell.

Do you grow tomatoes near where anyone else grows them,that
s an issue as well.

Almost all of the foliage diseases are spread by wind,and/or,embedded in rain drops.So depending on the direction of the wind and how much rainfall,also is an issue.

Once you get more info about the above,the easier it is for folks here to make some suggestions for you to help prevent it in the future.

Hope that helps,

Carolyn
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Old May 3, 2018   #3
gimmieToms
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Originally Posted by carolyn137 View Post
Blight is just a general word,it's important to know the specific kind of blight in order to answer your question.

Most blights in Canada affect the foliage as they do where I live as well and the most common ones are

Early Blight, which can appear either early or late in the season, bacterial

Septoria Leaf Spot, fungal.
L
Late Blight, P.infestans is a serious one .

Have you gone to the Disease Forum and looked at the pictures shown there to help make a diagnosis,that might help, especially the ones from Cornell.

Do you grow tomatoes near where anyone else grows them,that
s an issue as well.

Almost all of the foliage diseases are spread by wind,and/or,embedded in rain drops.So depending on the direction of the wind and how much rainfall,also is an issue.

Once you get more info about the above,the easier it is for folks here to make some suggestions for you to help prevent it in the future.

Hope that helps,

Carolyn
Late and early blight look pretty much the same to me. It came up in August. I had only had tomatoes a few weeks. There were black spots all over the stem and leaves which eventually went to the fruit and the plant would pretty much just die. Within two weeks of me noticing it, they were all infected and dying.
I'll see if I can find a photo
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Old May 3, 2018   #4
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here are my photos
Attached Images
File Type: jpg IMG_3336.jpg (641.7 KB, 99 views)
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File Type: jpg IMG_3340.jpg (324.0 KB, 100 views)
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Old May 3, 2018   #5
carolyn137
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Originally Posted by gimmieToms View Post
Late and early blight look pretty much the same to me. It came up in August. I had only had tomatoes a few weeks. There were black spots all over the stem and leaves which eventually went to the fruit and the plant would pretty much just die. Within two weeks of me noticing it, they were all infected and dying.
I'll see if I can find a photo
As I said above Early Blight can appear early or late in a growing season. Same pathogen,just a difference in timing. And yes EB can show black areas,especially on the lower stem.

What you seem to be describing is Phytopthera infestans,aka P. infestans as I called it in my last post. And when the first symptoms are seen the plants can be a rotting pile of vegetation within 5 to 7 days,RIP.

I want to take another look at your latest pictures to be sure I saw what I think I saw.

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Old May 3, 2018   #6
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Looks like Late Blight to me.

Bill
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Old May 3, 2018   #7
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here are my photos
Ok, do you see the small black dots on several leaves that have a yellow halo aroun dthem, that's probably early lesions of EB or Septoria Leaf Spot.

I see no symptoms at all for P.infestans but there's one disease that it has often been confused with and that's Gray Mold.

https://www.google.com/search?q=grey...&bih=815&dpr=1

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Old May 3, 2018   #8
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Originally Posted by carolyn137 View Post
Ok, do you see the small black dots on several leaves that have a yellow halo aroun dthem, that's probably early lesions of EB or Septoria Leaf Spot.

I see no symptoms at all for P.infestans but there's one disease that it has often been confused with and that's Gray Mold.

https://www.google.com/search?q=grey...&bih=815&dpr=1

Carolyn
So what would be best to use as a preventative this year?
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Old May 4, 2018   #9
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You need to ask Carolyn about prevention of Late Blight since it is a disease which we only see every few years if that often although I did have it two years in a row once. As to prevention of Gray Mold I have had the best luck with a copper spray. I know that Daconil is supposed to prevent it but I start out every season spraying weekly with Daconil because it works best preventing Early Blight; but I switch to copper when the first Gray Mold makes an appearance. Before switching to copper I do spray any infected plant and those next to it with a diluted bleach spray which really does a number on Gray Mold. I follow up two days later by removing all the shriveled leaves and then spray with copper. If the Gray Mold returns I repeat the process and can keep my plant alive indefinitely unless we enter a long rainy spell and then it is almost impossible to keep it from spreading; but even then by spraying the bleach spray between rains every day or two you can slow it down quite a bit.

Keeping your plants pruned so that air and sunlight can enter the plant will greatly reduce the chance of Gray Mold getting a good foothold and increase the effectiveness of your copper spray. One of the earliest and easiest signs of GM starting is a stem or a few leaves near the bottom of the plant and in shade wilting and looking dark and wet. It almost looks like damping off hitting a seedling. Another symptom is those light gray or grayish tan dusty looking spots on the tops of some leaves. If you see it early you can't wait too long to treat it as it has actually spread further up the plant than the visible symptoms. If left untreated for too long it will get into the stems and fruit and at that point the plant is probably not salvageable and even if it is there will be little foliage left after treating it.

Before I started growing black varieties I had never experienced Gray Mold but almost every year it will hit some of my black tomato varieties and some of the GWR varieties. I have only had it spread to red or pink tomatoes one time and that was because I didn't treat the nearby plants or spray them with any kind of fungicide until after it had spread. Late in the fall if we have any damp cool weather the GM will hit all my black varieties but if it is relatively dry with low humidity it will not spread that fast. It does seem to spread the fastest when the humidity is high and the plants are loaded with fruit. I have found that quick treatment, preventive copper sprays and pruning have made GM a controllable although bothersome nuisance. Late Blight is another kettle of fish as it strikes so fast and so hard.

I assumed Late Blight because I thought your plants were dead in two weeks and I have never had Gray Mold kill quite that fast but if you were saying that all your plants were infected in those two weeks then it could certainly be very advanced Gray Mold infection. If left untreated Gray Mold will slowly turn your plants into a mess similar to what Late Blight will turn them into only far quicker. I have only had plants get that wrapped up with GM three times. Once was at the end of the season when health problems prevented me from treating the problem but even then only a couple of the plants actually died from it before freezing weather finally ended them. Another time was a rainy summer and one Black from Tula plant that was in a very shady location and I just could never get the Gray Mold under control on that one plant because I waited too long to treat it initially. The other time was the first summer I grew some black tomato varieties and had no idea what I was seeing until it was far too late.

Good luck this year and I hope you don't have that problem again. I plan on setting out a fair number of black varieties and one GWR variety so I will probably have Gray Mold to some degree or another unless this low humidity we are experiencing now continues through the summer.

Bill
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Old May 4, 2018   #10
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That's either late blight or gray mold, and the way to say for sure is to look at affected fruit. Late blight has a characteristic oily dark looking big roundish splotches on the fruit, usually on the underside which are not soft (when the fruit is green) and somewhat bumpy.

Prevention is usually the same. Better conditions if possible, if not spraying with copper octanoate as preventive will help some but not much (there are also other more aggressive alternatives).
Better conditions mean: 1. no rain on the plants (greenhouse or at least a transparent roof over them), makes the biggest difference.
2. better spacing. That jungle you have there is fungus heaven. In late blight territory it's single stem or bust.
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Old May 4, 2018   #11
gimmieToms
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Quote:
Originally Posted by b54red View Post
You need to ask Carolyn about prevention of Late Blight since it is a disease which we only see every few years if that often although I did have it two years in a row once. As to prevention of Gray Mold I have had the best luck with a copper spray. I know that Daconil is supposed to prevent it but I start out every season spraying weekly with Daconil because it works best preventing Early Blight; but I switch to copper when the first Gray Mold makes an appearance. Before switching to copper I do spray any infected plant and those next to it with a diluted bleach spray which really does a number on Gray Mold. I follow up two days later by removing all the shriveled leaves and then spray with copper. If the Gray Mold returns I repeat the process and can keep my plant alive indefinitely unless we enter a long rainy spell and then it is almost impossible to keep it from spreading; but even then by spraying the bleach spray between rains every day or two you can slow it down quite a bit.

Keeping your plants pruned so that air and sunlight can enter the plant will greatly reduce the chance of Gray Mold getting a good foothold and increase the effectiveness of your copper spray. One of the earliest and easiest signs of GM starting is a stem or a few leaves near the bottom of the plant and in shade wilting and looking dark and wet. It almost looks like damping off hitting a seedling. Another symptom is those light gray or grayish tan dusty looking spots on the tops of some leaves. If you see it early you can't wait too long to treat it as it has actually spread further up the plant than the visible symptoms. If left untreated for too long it will get into the stems and fruit and at that point the plant is probably not salvageable and even if it is there will be little foliage left after treating it.

Before I started growing black varieties I had never experienced Gray Mold but almost every year it will hit some of my black tomato varieties and some of the GWR varieties. I have only had it spread to red or pink tomatoes one time and that was because I didn't treat the nearby plants or spray them with any kind of fungicide until after it had spread. Late in the fall if we have any damp cool weather the GM will hit all my black varieties but if it is relatively dry with low humidity it will not spread that fast. It does seem to spread the fastest when the humidity is high and the plants are loaded with fruit. I have found that quick treatment, preventive copper sprays and pruning have made GM a controllable although bothersome nuisance. Late Blight is another kettle of fish as it strikes so fast and so hard.

I assumed Late Blight because I thought your plants were dead in two weeks and I have never had Gray Mold kill quite that fast but if you were saying that all your plants were infected in those two weeks then it could certainly be very advanced Gray Mold infection. If left untreated Gray Mold will slowly turn your plants into a mess similar to what Late Blight will turn them into only far quicker. I have only had plants get that wrapped up with GM three times. Once was at the end of the season when health problems prevented me from treating the problem but even then only a couple of the plants actually died from it before freezing weather finally ended them. Another time was a rainy summer and one Black from Tula plant that was in a very shady location and I just could never get the Gray Mold under control on that one plant because I waited too long to treat it initially. The other time was the first summer I grew some black tomato varieties and had no idea what I was seeing until it was far too late.

Good luck this year and I hope you don't have that problem again. I plan on setting out a fair number of black varieties and one GWR variety so I will probably have Gray Mold to some degree or another unless this low humidity we are experiencing now continues through the summer.

Bill
Thank you. I will get some copper spray and switch to something more aggressive if I need to.
Very possible it was mold as I had some other plants grow what was much more distinctively mold on them..
It was a VERY wet summer, I had too many plants so they were much too close together and entwined. Perfect conditions for mold.
Out of all the years I’ve grown tomatoes, this is the first time I had this happen.
As a matter of interest my tomatoes were close to the house and my daughters laundry basket was under the window (she was only a couple months old), and I couldn’t understand why her clothes kept getting mold on them. I threw out so much clothes. It stopped happening after the tomatoes were gone. I’m guessing mold spores were coming in through the window.
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Old May 4, 2018   #12
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Quote:
Originally Posted by zipcode View Post
That's either late blight or gray mold, and the way to say for sure is to look at affected fruit. Late blight has a characteristic oily dark looking big roundish splotches on the fruit, usually on the underside which are not soft (when the fruit is green) and somewhat bumpy.

Prevention is usually the same. Better conditions if possible, if not spraying with copper octanoate as preventive will help some but not much (there are also other more aggressive alternatives).
Better conditions mean: 1. no rain on the plants (greenhouse or at least a transparent roof over them), makes the biggest difference.
2. better spacing. That jungle you have there is fungus heaven. In late blight territory it's single stem or bust.
The fruit had different kinds of splotches on them. Some started off a bit brown looking, some had shiny black spots and they all went rotten.
I had far too many plants (I have a problem with culling my seedlings lol), I had 25. This year I’m only growing 10-11 so will space them much better. We had a horrific wet summer. Very unusual for here. Days of rain at a time. It was terrible. Then high humidity when it wasn’t raining.
If copper doesn’t do the trick for prevention, what do you suggest instead?
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Old May 4, 2018   #13
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It looks like Late Blight to me and it's a killer. Plants die shortly after you discover that they are infected and once they are infected, there is no cure.

Late Blight is carried by the wind and lands on your plants so it usually starts at the top of the plants. Early blight usually starts on the bottom leaves and moves much more slowly. I have never had a plant die of EB but several years ago I had my entire crop wiped out by LB.

I spray Actinovate starting in Late July as a preventative. some people say that this does not work but I think that it helps. If I would happen to see a plant infected with LB , I would immediately pull it out because there is no hope it will survive and spray the rest of them with copper.

LB arrives here in August when days are humid and nights are cool. When the nights are still hot like in July LB is not an issue.

I get my tomatoes started early enough that if LB gets them in August, it's still sad but at least by then I have already had a decent harvest.
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Old May 4, 2018   #14
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It looks like Late Blight to me and it's a killer. Plants die shortly after you discover that they are infected and once they are infected, there is no cure.

Late Blight is carried by the wind and lands on your plants so it usually starts at the top of the plants. Early blight usually starts on the bottom leaves and moves much more slowly. I have never had a plant die of EB but several years ago I had my entire crop wiped out by LB.

I spray Actinovate starting in Late July as a preventative. some people say that this does not work but I think that it helps. If I would happen to see a plant infected with LB , I would immediately pull it out because there is no hope it will survive and spray the rest of them with copper.

LB arrives here in August when days are humid and nights are cool. When the nights are still hot like in July LB is not an issue.

I get my tomatoes started early enough that if LB gets them in August, it's still sad but at least by then I have already had a decent harvest.
This all started at the bottom of the plant.
I’d had a baby mid June, so wasn’t as attentive to my plants as I usually am. The leaves had started to yellow at the bottom, and before this all took hold I had some pictures that I took where you could see it starting on the stems. Splotches of black. I just hadn’t noticed. So it’s possible it started much earlier. I only noticed when I went out one day and a plant was almost dead. It happened over night. Those are the pictures above.
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Old May 4, 2018   #15
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It looks like you may have some EB also The brown areas with the yellow around them is probably EB and those spores are usually in the soil and splash up onto the plant which is why EB starts at the bottom.

As far as I know LB does not cause any yellow leaves. At least it never has for me. I just start seeing irregular brown blotches and Poof! within a week the plant is dead. I tried cutting off the infected leaves and branches the first time I ever saw it but it was no use, the plant died anyway. Now if I see LB I immediately remove the plant to avoid spreading the spores which will develop under the leaves and look kind of whitish and fuzzy. Like I said - it's a killer.
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