What is this disease?

[cwavec]

I have encountered an apparently fungal foliar disease on my tomato plants.
I do not recognize it, although I have already had some kind of mildew
infection and seen first signs of early blight. This appears to be the
early stages of something else.

I'm going to post photos in the hope that someone can identify this and I
profoundly hope that it is not what I suspect it is.

Photos A1 and A2 - underside and top of leaflet A

Photos B1 and B2 - underside and top of leaflet B

Photos C1 and C2 - underside and top of leaflet C

The leaves, while still on the plant, have a kind of bronze look,
although still green. Some have a black edge. This is occurring
on upper and lower leaves at the same time and began a few days ago.

I have searched as many online descriptions and photos as I am
able to find in a short time and unfortunately the only ones I see
that look anything like this relate to Late Blight. There have already
been reports of Late Blight in Susquehanna County (northeast PA)
and nearby there in NY state. I am just north of Pittsburgh.

[cwavec]

I have reported the outbreak, if that is what this is to the Late Blight reporting system
and will submit samples if desired.



There is a report and sample submission protocol at:


http://www.usablight.org/?q=submit_p...495740734&of=0


and anyone else suspecting an infection of this should at least register and
send a report.

[cwavec]

Here is the initial reply I just got from one of the plant pathology experts at Cornell:


Based on the photos you sent, your tomatoes do not have late blight. It actually looks more like a nutrition issue than a disease. I have forwarded your pics to others for their input.

[AlittleSalt]

I would say they are thinking it is a nutritional type thing in pictures A1 and A2 in particular. Which nutrient/s they need - I don't know? Others here may have a better idea on what it could be.

[Johnniemar]

Possibly to much nutrition?? To much fertilizer, just a guess.

[brownrexx]

I don't know what it is, but I have had Late Blight in the past and that is definitely not it.

[nbardo]

Do the discolored parts feel different than the normal leaves? Are they dry and crinkly or damp or just feel like normal leaves?


Sent from my iPhone using Tapatalk

[cwavec]

@AlittleSalt, @Johnniemar, @brownrexx, @nbardo


Good points all. I'm still in contact with the plant pathologists and
there may be more to say but for now:


There has been the suggestion of too much fertilizer although I don't
use much. Each plant has had a total of 2 oz. TomatoTone. The
nutrition expert at Cornell says the rec. is 3 TBSP, which would be
1- 1/2 oz. I don't think the difference here would cause problems
especially as 1 oz. was mid-May and 1 oz. now. So I will reduce it
a bit next year.


I have also had Late Blight here and fought it for 4 years until it
was gone. So I do know what it looks like but the question was if
this could have been a very early stage of infection. Some photos

online look like this but evidently the answer is no.


The discolored parts do not feel any different.

[bower]

Pics B1 and C1 look like some kind of insect damage to me, starting from below. Brown spots etc would be necrosis caused by the feeding.

I've had some leaf scorching here that could be mistaken for blight - that is when it became suddenly really hot and sunny after extended cool and cloudy weather. But when you remove the crispy critter leaves, the plant is fine. Blight OTOH will spread rapidly and will kill the plant within days afaik.

[cwavec]

I am quite sure by now that this is not late blight. Although these pictures
bear some resemblance to the appearance of a very early stage infection
the later developments are not the same and not as fast.


I believe the pathologists evaluations are pretty definitive. Additionally,
I mentioned phytotoxic effects as a possibility but do not really think that has happened.


One more thing I would like to know is whether the colonising of the leaf
surface by Serenade is visible and if so, what it looks like.