Is this all tomato blight or something else?

jen1996August 29, 2012

Hi all.

Last week I realized I think all of my tomato plants have blight .... or some thing.

Below are pics.

In general I think the plants are are quite healthy growing and producing rapidly.

The second two pictures are of what I thought was blight.

It is the last picture I am unsure of. Is this blight or something else. The spots are tiny and more numerous. One plant has many leaves with these spots but the plant is otherwise strong and healthy looking.

So far what i have done for the plants is mulched with grass clippings, picked off infected looking leaves and sprayed with a baking soda solution.

Re blight should i be picking every single leaf at first sign of yellow or spot or wait for it to become more appearant that it is blight?

How often can i spray the baking soda solution?

Thanks

Jen

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edweather(Zone 5a/b Central NY)

I'm not disease expert by any stretch, but the good news is that it doesn't look like blight. Blight would knock the heck out of the whole plant in about 3 days, and you'd have nasty looking lesions all over the plant including the branches. Looks more like a wilt of some kind. If it were mine, I'd remove the bad foilige and spray asap. I spray with Daconil.

    Bookmark   August 29, 2012 at 9:42AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Check out the Growing Tomatoes forum here (linked on this forum's page). Many discussions there about "blight" - it is just a catch-all label for all sorts of possible diseases and had little meaning on its own.

You'll also find info there on the various fungicides recommended for controlling each disease as they all have different causes.

Dave

    Bookmark   August 29, 2012 at 12:23PM
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jen1996

Dave
I posted over at the tomato forum and sifted through numerous posts.
I have not seen anything that looks like the last pic I posted.
I also have not found the answers to the questions I had in any of the posts I have sifted through.
i thought I might have better luck here.

Since I last posted I am now seeing many more leaves that look like the last pic which do not look like the blighty lookings pic I have seen.
I sprayed heavily with the baking soda last night and now I an wondering if those rashy looking spots is more of a reaction to the spray.
I ordered some Serenade to try instead.

    Bookmark   August 29, 2012 at 2:39PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Sorry if you didn't get direct replies on that forum but after about the 50th time a post titled "Is this blight?" goes up folks tend to ignore the posts since all the info is already there.

But if you have read through them then you have already read about the standard fungicide recommended - Daconil applied weekly from day of plant out, about why baking soda has little to no effect, and that fungicides are preventatives and not cures so heavily mulching the plants when first planted rather than leaving them in bare soil can prevent many of the problems?

Also discussed in depth is when copper-based fungicides work best and when they won't, the various symptoms of Alternaria vs. Septoria Leaf spot vs. Early Blight - you have both Alternaria and Bacterial Speck - and have checked out the tomato disease diagnosis web site links provided in those discussions?

If so then there is really little that can be added to all the info posted over there.

You can try Serenade if you wish but as others have pointed out in all the previous discussions there, once the disease is established it has little effect.

If it were earlier in the season then more aggressive treatments might be recommended. But your plants don't look bad at all and this late in the season there is little to be done except to keep removing the affect foliage to slow the progression of the diseases down until the fruit can ripen. Granted you don't indicate your zone or location but from the plant size the season is clearly winding down so investing lots of $$ and energy now will get little if any return. Still these are all good lessons - mulching, fungicides, specific disease symptoms and their cause, early signs to watch for, etc. - to be learned for next year.

Dave

PS: TAMU Tomato Problem Solver

Here is a link that might be useful: Is this blight discussions

    Bookmark   August 29, 2012 at 3:34PM
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jen1996

Dave
First, I apologize if my post as a newbie here is annoying as or seems repetative but as I said I did not see the answers to the questions I had (like is the last photo blight or something different)
I was not asking for recommendations on fungicides. I would NOT use copper and after reading this article
http://www.tampabay.com/news/environment/wildlife/usf-study-concludes-that-common-fungicide-is-deadly-to-frogs/1162355
reluctant to use dacanil.
I opted for baking soda because I have read several times it is effective
http://www.veggiegardener.com/tips-for-preventing-and-treating-tomato-blights/

I have also read serenade is effective and recommended by some
http://umaine.edu/ipm/ipddl/publications/5087e/

Yes, in fact I have checked out many of the links re the dx websites and is another reason why I posted. My last picture does not look like and of the blight pics I have seen. Hoping someone here might recognize it.

Lastly,
Yes all of these issues I have had (much more beside the tomato problems) have all been great lessons.
I am very excited for next year and hopefully have even more success.

Thanks for your reply.

J

    Bookmark   August 29, 2012 at 10:20PM
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chaman(z7MD)

It looks like your plants need more water and micro nutrients.Transpiration is one of the cause for yellowing of leaves.Keep entire garden soil evenly moisturized.

    Bookmark   August 30, 2012 at 9:21AM
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lgteacher(SCal)

I vote for alternaria (early blight). The brown spots with yellow around them are characteristic of this disease. It generally starts with the lowest leaves. Remove the bad leaves to slow it down so the tomatoes on the plant can ripen. Don't add these plants to your compost, and don't plant tomatoes in the same soil next year. I had this too, probably because it was damp in the early part of summer. It doesn't look like your plants need more water.

Here is a link that might be useful: What's Growing On?

    Bookmark   August 30, 2012 at 10:29AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Jen - no need to apologize. it isn't anything you did wrong. It is just a fact of life on most forums any time the same question gets asked over and over. Respondents get tired of typing all the same information over and over.

But for future reference don't worry so much about matching photos as the same disease can look 100 different ways in 100 different pics unless they are detailed closes ups of the leaf. Instead focus on all the information provided in the posts about controls.

The primary goal is to narrow it down to class - one of the fungal diseases which are 80% of them or one of the viral diseases for which there is essentially no treatment. If it is one of the fungal diseases then all have the same basic treatment - strip off affected leaves and regular spray with fungicide. If you choose to not use fungicides then in the end it doesn't really make much difference which disease it is.

As to fungicides, that is your choice as long as you understand the effects/end results of those choices. There are many pros and cons for all of them as well as many false claims about all of them. Many strictly organic gardeners choose to just lose their plants rather than use some of the fungicides. However some of the copper-based fungicides are organically approved so take care when ruling them out as well.

Dave

I vote for alternaria (early blight). The brown spots with yellow around them are characteristic of this disease.

Alternaria and Early Blight are two different diseases with different fungal causes and different symptoms.

    Bookmark   August 30, 2012 at 12:56PM
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keithondelmarva

Early blight is an Alternaria species, A. solani. and that is what it appears to be.

    Bookmark   August 31, 2012 at 11:23PM
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lgteacher(SCal)

Source: Arizona University extension

Alternaria, early blight

Early blight of tomato is caused by the fungus Alternaria alternata f sp. lycopersici. Symptoms become prevalent during the hotter months and with high humidity and rain. In Arizona, it occurs sporadically during the summer "monsoon" rainy season, especially in southeastern Arizona. This disease produces brown to black, target-like spots on older leaves that may coalesce into larger lesions (photo 1). Affected leaves may turn yellow then drop, leaving the fruit exposed to sunburn. If severe, the fungus also attacks stems and fruit. Fruit shows freckles, spots or lesions (photo 2 , photo 3 ). Often the spots are not evident until a few days after the fruit is harvested.

To manage disease, remove all diseased plant tissue on the ground, as the fungus overwinters on leaf debris. Sanitation is the best control. Do not plant tomatoes in the same place next year. Avoid overhead irrigation and space plants farther apart to improve air circulation. Plant resistant varieties. If the infestation is heavy, sulfur dust may help protect new leaves from infection (do not apply sulfur dust above 90oF). Other fungicides such as chlorothalonil (Bravo, Daconil) and azoxystrobin (Quadris) are effective in preventing diseasse.

    Bookmark   September 1, 2012 at 11:14AM
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hcoon(5a)

Last year I started spraying my tomatoes with Seranade early in the season and kept it up as the plants developed disease. By the middle of the season it took a couple of hours each week to spray everything.

I had a second garden plot a couple miles away this year which took extra time, so I decided not to spray my tomatoes with anything and see what happened. I just pulled off the diseased leaves.

Granted, I haven't ever used anything like copper or Daconil, but I've found that my plants -- which started having symptoms in July -- are all still alive and putting out tomatoes despite all having some kind of disease. If the disease is slow moving, perhaps doing nothing is an option. Especially so late in the season. After all, these plants only need to stay alive a few months.

    Bookmark   September 2, 2012 at 9:31AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Misuse of labels in the home gardening community (vs. the commercial industry) is common but there are distinguishing characteristics. To further compound the problem, some refer to Early Blight as Alternaria Leaf Spot and to Early Blight as "Blight" when there are 3 different types of blight with different causes, symptoms and treatment.

So,

Alternaria (full name Alternaria Canker) is caused by the fungus Alternaria alternata f. sp. lycopersici. It affects the leaves, stems, and the fruit of a tomato plant (fruit and stem affectation being the primary distinguishing symptoms between it and Early Blight).

That particular fungus can overwinter in crop residue and is also airborne. Leaf symptoms are large areas of brown dead leaf lamina between veins, leaf curling and eventual death of the entire leaf. Fruit are infected when green and display small gray to black lesions that look like shotgun pellets scattered over the fruit. The spots persist through ripening. On stems very large, dark brown cankers form and dry and split. The cankers wrap around the stem as they enlarge, killing the entire plant. Pruning of plants provides an ideal entry point for this disease.

Early Blight is caused by the fungus Alternaria solani (different fungus) and primarily affects only the leaves of the plant with characteristic small brown spots surrounded by yellow bands that have a concentric banding appearance often called a target or bull's eye.

The fungus does not over-winter but is also airborne. It is primarily warm, wet weather triggered vis entry through the stoma of the leaves. Symptoms of any affect on the stem is described as low on the plant main stem, narrow, light brown, sunken lesions. Fruit is not affected.

Both diseases respond to the use of fungicides although they do not cure the disease, just slow its progression. Studies have shown the Alternaria has a much higher plant mortality rate and is much more resistant to fungicides than is Early Blight but will respond to alternating treatments of a copper based fungicide followed by applications of Chlorothalonil. Early Blight is easily prevented with preventative spraying and moderately well controlled by the use of copper based fungicides only.

Hope this helps clarify and for more information please see all the detailed discussions of this topic over on the Growing Tomatoes forum here.

Dave

    Bookmark   September 2, 2012 at 2:17PM
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