Septoria? and Late Blight?

emcd124(5)July 12, 2012

Two of my tomato plants seem to have some progressive disease issues. When I first noticed it and snapped pictures, I was told that it was likely just heat damage from the hot spell we were having (100+). I removed all the leaves then, and temps have been more moderate since, but I still have newly damaged leaves. The two most affected plants are the Roma and the Black from tula, but the disease look very different on both.

These are from the Roma, as you can see from the first photo, the damage is mostly on the bottom of the plant, involves lots of yellowing of the leaves, some necrotic circles, and some leaves eventually wither entirely:

These below are from my potato-leaf "Black from Tula" which is in the adjacent raised bed, about 5 feet away. It has no yellowing as far as I can see, and the fruits and stems look completely strong and healthy. I didnt search every inch, but I didnt find any discoloration on the stems.

I wasnt able to capture it well in the photos, but the brown/grey areas on the BfT are almost irradescent in the light.

And there's also this gem, found on the back of one of the leaves of an otherwise healthy looking plant:

Heaven help me! Ideas what is going on with the plants? After staring at a number of online diagnostic sites, the Roma looks like it has Septoria combined with maybe Late Blight, maybe heat damage. The BfT looks like late blight, but is there another possibility? Could it be heat damage? Per the recommendation of these forums, I've gone entirely with soaker hose irrigation so the leaves dont get wet (except from rain) combined with straw mulch to keep the roots cool and balance out the moisture.

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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

but the disease look very different on both...After staring at a number of online diagnostic sites, the Roma looks like it has Septoria combined with maybe Late Blight, maybe heat damage. The BfT looks like late blight, but is there another possibility?

Did you notice in your research that the treatment for all of them is the same - remove all affected foliage and begin a regular fungicide spraying program?

In other words, rather than focus on exactly which disease it may or may not be - and it may indeed be any one of the three (Septoria, Alternaria, Late Blight) or some of all three combined - focus on the treatment instead and saving the plants as much as possible.

If it is Late Blight then you will quickly know it as it will spread to the stems and that will be the end of the plant. If it is just Septoria or Alternaria or even Early Blight then the fungicide, if applied ASAP, will slow it enough to salvage the fruit. Meanwhile you can take the leaf samples to your local county extension office for a hands-on diagnosis.

We do the best we can with 2 dimensional pictures - which is only a recent addition as we used to have to do it all from just a description. But no one would intentionally steer you wrong and nothing says that the first pics couldn't have been environmental damage and then the diseases developed later.

And "going entirely with soaker hose irrigation so the leaves dont get wet (except from rain) combined with straw mulch to keep the roots cool and balance out the moisture" is always a good idea with no negative side effects whatsoever.

So shift your focus. Get those leaves off the plants ASAP and begin spraying regularly with your fungicide of choice.

Good luck.

Dave

    Bookmark   July 12, 2012 at 5:58PM
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emcd124(5)

I am so sorry! I didnt mean to imply that I thought someone gave me misinformation about the heat damage, more just as additional information that some or all of it still could be from heat damage, and I wasnt clear how to tell that from the other alternatives, so I put it out there for consideration. I am deeply grateful for the learning and guidance I've gotten on here. I'd have killed everything months ago if it werent for these forums!

Okay, went out there and cut off every part with damage showing whatsoever, but it was a pretty dramatic "hair cut" in some cases. I had a bottle of Serenade organic spray on hand and went to town with that, spraying all the surfaces. I'll head out to a garden store tonight after work and see what else I can pick up.

Fingers crossed! Ugh, I'm so discouraged that between the rabbits and this now, more than half of my garden has been decimated. I hope I can save at least some of the tomato plants!

    Bookmark   July 13, 2012 at 10:24AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

I'm so discouraged that between the rabbits and this now, more than half of my garden has been decimated.

I know it can get discouraging when our expectations exceed our success but don't let it get you down as it is all a part of gardening. But so is optimism each year.

Just think of all you have learned and so can fix or prevent for next year. No matter how many years we have been gardening we are all still learning each year.

Rabbits can be fenced out and while we can't control the weather we can prevent or at least discourage many of the common diseases by using fungicides early on. Especially when the weather patterns indicate they will be a problem. Way back in late February-early March when the unusual and weird weather patterns began in much of the country we were warned that fungus problems would likely be an issue this season. And sure enough they have been for many of us.

So chin up! You aren't alone. And we all hope next year will be better. :)

Dave

    Bookmark   July 13, 2012 at 12:19PM
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