Information and discussion regarding garden diseases, insects and other unwelcome critters.
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May 3, 2018 | #1 |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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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. |
May 3, 2018 | #2 | |
Moderator Emeritus
Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
Posts: 21,169
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Quote:
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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Carolyn |
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May 3, 2018 | #3 | |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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I'll see if I can find a photo |
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May 3, 2018 | #4 |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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here are my photos
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May 3, 2018 | #5 |
Moderator Emeritus
Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
Posts: 21,169
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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
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Carolyn |
May 3, 2018 | #6 | |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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Quote:
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May 3, 2018 | #7 | |
Moderator Emeritus
Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
Posts: 21,169
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Quote:
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. Carolyn
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May 3, 2018 | #8 |
Tomatovillian™
Join Date: Sep 2009
Location: Alabama
Posts: 7,068
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Looks like Late Blight to me.
Bill |
May 4, 2018 | #9 |
Tomatovillian™
Join Date: Jun 2010
Location: Romania/Germany , z 4-6
Posts: 1,582
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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. |
May 4, 2018 | #10 | |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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Quote:
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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May 4, 2018 | #11 |
Tomatovillian™
Join Date: Feb 2016
Location: Southeastern PA
Posts: 1,420
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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. |
May 4, 2018 | #12 | |
Tomatovillian™
Join Date: Jun 2016
Location: canada
Posts: 46
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Quote:
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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May 4, 2018 | #13 |
Tomatovillian™
Join Date: Feb 2016
Location: Southeastern PA
Posts: 1,420
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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. |
May 4, 2018 | #14 | |
Tomatovillian™
Join Date: Sep 2009
Location: Alabama
Posts: 7,068
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Quote:
I now treat Gray Mold just as quickly so it is far less of a problem than it has been in the past when I would procrastinate and wait to be sure. Every time for the past few years when I thought I had it I did. It used to always surprise me how far the stuff extended up the plant above where I saw the signs of Gray Mold. The diluted bleach spray will basically kill any foliage that has Gray Mold and the shriveled leaves 2 days after spraying show how much infection there actually was. I urge anyone who deals with Gray Mold or who wants to attempt to slow or stop LB to read the diluted bleach spray thread on this site before using it. Oh yes LB can strike in the hot middle of summer. It did it twice in my memory of over 40 years of growing tomatoes. The first time was over 30 years ago and I had no idea what killed all my tomatoes in less than two weeks and did the same to everyone else near me who was growing tomatoes. We finally found out from the county agent that the culprit was Late Blight. The last time was several years ago so now I check for it from early summer til it freezes. Bill |
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May 4, 2018 | #15 |
Tomatovillian™
Join Date: Feb 2015
Location: NC - zone 8a - heat zone 7
Posts: 4,915
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On the general subject of PREVENTION.
I thinks that a good systematic spraying with fungicide can help prevent the spread and infestation. I use 3 types alternatively. DACONILE COPPER NEEM OIL. I have found bleach spray effective on Grey Mold . That happend every late season up in PNW. It can happen down South too, as Bill has experienced. That is due to too much rain and/or high humidity. We know that mold thrives in moist and humid conditions, like in damp cellar. And of course bleach is to the rescue. I would use it according to Bill,s mix. So far this season I have sprayed with copper twice already. The next time I wiil do with Neem and the following round with Daconile. Inline with preventive measures , I believe in pruning, to lighten up the foliage, especially the lower leaf branches, to accommodate good air flow.
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Gardeneer Happy Gardening ! |
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