Septoria leaf spot

Dave

Thanks for that. Because I haven't planted these seedlings yet, do you think I should just chuck them and buy new ones? It says that I can control the leaf spot with fungicides but not cure it, so at this point would it be worth it?

No cure, just a limited control from fungicides. So if healthy transplants are available then yes you'd be better off using those and tossing these.

Dave

Well that's discouraging since I raised these from seeds, but thanks for your advice. I guess it's better they had these issues before I even planted them.

IMHO that is not septoria... definitely not if those plants are indoors!

That looks environmental or nutritional to me. Those spots are purple, at least in the photo.

They've mostly been outdoors lately as I'm hardening them off to get ready for planting.

Those spots are brown, not purple, though I agree they do look kinda purple in my picture.

"IMHO that is not septoria... definitely not if those plants are indoors!"

That can easily be caused by the dirt they were started in. But yes if you haven't planted them yet chuck them out. You risk contaminating your garden soil for years. The spores are in my garden. I grow resistant varieties and battle it aggressively. At least with sepotoria the fruits aren't attacked so I get a few for eating but definitely not high enough yields for saucing

Dave is tough to beat on diagnostics but Septoria may not be the only thing you have going on there so Peter may be on to something as well. I would have said possibility of some mite activity with that tarnished look around the spots. All in all though, not worth starting all over again, in my experience with Septoria it can be kept under control with a rotation of fungicides and does not adversely effect yields, it is very common around where I grow and hard to not have some of it. According to Cornell it does not persist in soil and only transfers through crop debris from season to season. It is the best disease issue to have by far.

Septoria needs moisture and humidity to both spread and grow... I just don't see it growing like that indoors. It usually does not show up for me until July.

Septoria is ubiquitous. Just about everyone battles it every year, and it is not soil borne, nor will it survive a zone 4 winter. It is spread far and wide by wind.

That picture also does not look like Septoria to me. See the images below of Septoria. Note the small round lesions with the yellow haloing.

That is also definitely not early blight or late blight IMO.

Hmm OK. Well in the week since I first posted this is what the leaves on my worst plant look like. Does this give any more clues? Thanks again for all your help.

Well I am in zone 4 Mosinee WI and it sure survives the winter here.

I think Peter may have been right all along. Those deep purple stems indicate a possible phosphorus deficiency due to lower than ideal soil temps or pH lockout and possibly either magnesium or calcium deficient as well judging by the chlorosis pattern. This damage also looks similar to mite damage. Look into all these and decide for yourself.

OK thanks so much. I've never dealt with mites before but I've read about them, so I will check the plants tomorrow. It definitely could have been cooler night temps as we've had a few colder than usual nights. Thanks again, I'm just glad it's not blight as I just started gardening at our house and I'd hate to introduce anything like that to my soil.

That is not blight.. or septoria. What are you fertilizing with? Have you planted them? What are you growing them in?

Unfortunately not all fertilizers have micronutrients. Planting them should hopefully help with that though. Like hokie mentioned your mix could also have ph issues.

While I stand by my initial diagnosis, I agree with Peter that this latest photo is totally unrelated to and displays totally different symptoms from, the original post.

This can be an excellent learning situation for you IF you make note of and research those very different symptoms. While researching, be sure to note that none of the issues under discussion can be "introduced to your soil" as they are already there and in the air blowing by.

Your original pics were disease, this latest pic is nutrient deficiency.

As for pests - they are the very first thing you should be looking for when you discover a problem as they are 50 X more common than either disease or nutrient issues. We often mistakenly assume when someone posts a photo that they have already ruled out pest issues since it is so easy to do through simple examination and because they can't be seen in the photo.

Personally, from the latest photo, I don't see any of the common symptoms of mites but that doesn't mean they aren't there - only you can tell.

What is there now is nutrient deficiency, probably phosphorous, possibly others, that can be caused by several different issues. So for clarity - have these been planted out or are they still going in and outside, if not planted yet, whY?, if still in containers what size, are they root bound, what exactly do you feed them and how often?

Dave

First pic looks like it was fungal or from a folliar spray. 2nd pic Looks like mites, a nute lockout, or old sunscald. as in a wet unknown substance was on the leaves during high sun, Cold nights below 4c would very well do it too if this is old damage we're looking at. It's also indicative of a plant that was water logged and incurred a nute lockout, Ensure proper watering if potted.

I stand by my opinion that is not septoria in the first pic. But we are all entitled to our opinions... there can be no definitive diagnosis from a single (oddly colored) photo...

moraine_gw: They've mostly been outdoors lately as I'm hardening them off to get ready for planting.

That could well be burn. What does your hardening off process look like?

Is ALL of the foliage on the plant affected with spots except for the very newest baby leaves?

Did the spots show up since going outside, or were they on the plant indoors?

And have you sprayed your plants with anything? Foliar fertilizer? Pest or disease control?

These tomatoes have not been planted in the ground yet, they're only in containers. They are in bagged potting soil (Miracle Gro I think). I haven't fertilized them since they were much smaller, and it was with a Miracle Gro tomato fertilizer that I diluted in water. I haven't sprayed my plants with anything.

I don't believe all the old foliage is affected, but I can confirm that later on. I checked them over for spider mites, and I didn't see any signs of them.

For hardening, I let them out a few hours at a time at first, though I'm sure I have left them out some nights that were a little too cool for them since then, and we've had some fluctuating temps between night and day. They've been exclusively outside now for the past 2 weeks or so. I believe the spots first appeared when they were outside.

I can take some more pictures later today of my plants if that would be helpful.

And when I say "introduced to my soil", I read that blight spores can survive in the soil over the winter, and I'd rather not make it easier for them by planting affected plants in my garden. Maybe I was wrong on that, though.

If they have been in containers all this time then they are very likely root bound. You don't mention the size of the containers but anything less than a 6-8" pot simply doesn't hold a plant that long. Since it is easily planting out time in your zone then I'd say plant them. That alone could quickly resolve all your problems seen in this latest photo.

For future reference you might want to do some research into proper "hardening off" processes as what you describe doing is an unusual approach and quite stressful to any plant.

Dave

PS: yes some fungi, not all, can over-winter on plant debris depending how harsh winter is in your location although that far north it would be rare. But that in no way means the fungi spores weren't already there to begin with. It is the viruses that we can introduce to our soil, not the bacteria or fungi.

Most all of the various so-called "blight" fungi are air borne spores and already exist in most soils that haven't been sterilized. They just need the ideal conditions to grow and become active. If they don't get those conditions they remain dormant.

Pictures of the whole plant/plants would be helpful.

OK, really interesting info. I've gardened the last few years, and I've never dealt with septoria or early blight, but I dealt with late blight one year and it was terrible, so I'll admit I panicked when I saw the leaves on my current plants.

I know there's definitely a "proper" way to harden, and usually my method is not so... stressful on the plants, but busy schedule this season made it very difficult for that. Next year I'll try better at hardening them off to prevent making them vulnerable.

I'm still trying to figure out planting times for my area for warm-season plants, and I hesitated to plant them so far because some nights still go below 10C. If it's a good time to plant now though, I'll plant them out as soon as I can weather-willing.

Thanks everyone for the info, I'm kinda floundering my way through this (with research thrown in), and it's definitely fun, but sometimes it's frustrating...