Help requested with ID of this leaf issue

[huntsman]

Hi!




I've suddenly spotted this problem on two of my plants, both with Potato leaves. (No idea if that's significant). The plants have been in the ground for about 5 weeks now and one has fruit (still green) while the other does not. It is now Summer where I am.







Any ideas on what the cause might be?

[huntsman]

Too much of something?

Too little?

[carolyn137]

RL or PL, it makes no difference with respect to diseases, with few exceptions IMO/

In the background I can see some of the smaller branches that are wilting and that wouldn't be typical if it were only a foliage disease, it would indicate possibly a systemic soilborne disease.

How many plants do you have inground and how many are affected and did you raise all of them from seed or purchase some?

And I'll say that I don't know what the most prevalent diseases are where you live and garden and there are regional differences. All to ask if you have what we call Cooperative Extensions there which are usually associated with Universities and are a great resource in terms of often helping with local disease ID's.

[huntsman]

Hi Carolyn -

I have seven toms in an area 20' x 8', and three are affected. I raised all of them from seed found on the site...

We have no system of co-ops here that I have ever heard of, so I think it's sink or paddle...

Meantime, I have removed all problem foliage and discarded it.

Carolyn, I have just installed a mister system for the first time; could this be over watering? Watering directly onto the leaves?

[b54red]

Can you post a good picture of leaves that are showing the first signs of the disease and the new growth tips on the stem that has the symptoms?

[Worth1]

Too much nitrogen can cause similar symptoms but not quite like the pictures show.

I see spots and the foliage isn't dark enough.

Worth

[huntsman]

No more pics as we have cut them all off and destroyed them...sorry b54 red.

Doubt it's Nitrogen, Worth1 - we've been very diligent with organic ferts and the rest of these plants and all others are a good green.

It's quite puzzling....much like they have been hit by frost which is impossible.

[carolyn137]

Originally Posted by huntsman

Hi Carolyn -

I have seven toms in an area 20' x 8', and three are affected. I raised all of them from seed found on the site...

We have no system of co-ops here that I have ever heard of, so I think it's sink or paddle...

Meantime, I have removed all problem foliage and discarded it.

Carolyn, I have just installed a mister system for the first time; could this be over watering? Watering directly onto the leaves?

It is possible that there's been overwatering of the foliage and the bumpy surface of PL varieties would hold the water longer on the leaf surface. What times of day do the misters turn on, full sun, partial shade, night, etc.?

But what still concerns me are the small lateral branches in the background that are wilted, the question being did you see wilting on any of the other plants or just the PL plants affected?

It doesn't look like too much N to me since all the plants should have shown that and usually it's just tip burn and often black margins along the leaves.

[huntsman]

We've been watering manually (via sprinkler) in the late afternoon for around 30 minutes, and only when the plants have either weak sunlight or shade.

Just in case this is the problem, I've hammered the sprinkler stakes as deep into the ground as I can, so they spray much lower, but I have just finished watering for the day, and the plants are all soaked, leaves and all...

I haven't seen any wilting at all, until I spotted the damaged leaves. All other plants seem really healthy. Most vexing...

[Suze]

I would suggest watering much earlier in the day, so that the foliage has plenty of time to dry out before the sun drops.

Edit - especially since you are watering via sprinkler. I sometimes water in the evenings, but I'm using netafim drip tubing and it gets no water at all on the foliage when irrigating.

[Suze]

I'll suggest botrytis / gray mold as one possibility. What you're showing (mostly) seems to start at the tips of the leaves. One thing that also caught my attention is that large "water-soaked" lesion at the bottom right corner of your first photo.

Botrytis can affect/infect the surface of stems externally and even frequently move below the surface, causing some superficial "wilting" in the affected areas, especially at the growing tips / newer growth on a plant. I've seen it do that in my own garden.

However, I am seeing some lesions on your plants that might suggest other problems - but if so, my guess is that they are likely fungal as well. That second photo is kind of throwing me, I'll admit.

[huntsman]

Thanks, Suze -

I had considered replacing the misters with a drip system, just in the area of the tomatoes, but of course that will be negated when I rotate their position next year...

I'll ensure that I do not use the misters other than early morning.

Is this a problem that requires I remove the bushes entirely?

[Suze]

Originally Posted by huntsman

I had considered replacing the misters with a drip system, just in the area of the tomatoes, but of course that will be negated when I rotate their position next year...

I'll ensure that I do not use the misters other than early morning.

Ah, I see - it sounds like you have a bunch of misters in place to water "everything" in your yard? If you can shut it off for just those areas that your tomatoes are in and hand/hose water until you figure something out longer-term, I would highly suggest you do so. If not, yes - just try and run those sprinklers early in the morning in that area if you can.

I will also offer that there is really not a need for the home gardener to be constantly rotating for their tomato crops. Yes, that is frequently standard fits-all advice, but if you don't have any systemic problems in the soil or root knot nematodes, I would not worry too much about doing so every year.

Point is, I think you could decide on an area for the next few years where you will be planting your tomatoes and make irrigation plans accordingly.

Yeah, sure - the soil can get a bit tired if you grow in the same area year after year, but that can be mostly or even completely mitigated by adding lots of organic matter regularly.

Is this a problem that requires I remove the bushes entirely?

If your other plants are not affected so far, I would not worry too much about it, and just do what you can do. If you see any diseased foliage remove it asap, also clean your pruning shears in between cuts in rubbing alcohol if you can. Also try to water only early in the day as suggested before, and/or hand water, use soaker hoses or drip tubing instead.

Btw, I looked at your pics several times, even enlarged them on my screen, but alas cannot offer a definitive "this is it!" answer. I do see some definite signs of botyrtis though, although I think there may be some other things going on though. (all or most likely fungal; some of the spots in the second pic sort of looked like Septoria, but I'm not sure)

Botrytis tends to hit early in the season, frequently before the plants even start to set any fruit of note. It takes hold fast, and favors cooler nights (like one would see earlier in the season) and moisture on the foliage.

It also tends to be rather under-undiagnosed, at least on gardening forums in general. Frankly, I get a few plants every year that are affected with this at least to some extent early in the season, and for years I did not even know what it was.

Last year I made the connection, and finally realized it was botrytis. Dur. If Feldon is reading this, I know he knows what I am talking about. He's been though the same thing with this occasional "black crud" too, even more so because it tends to be more humid in Houston because it is a couple of hours closer to the coast than I am.

Anyhow - I think the problems you have look to be mostly or entirely fungal. Since we've already discussed the watering, I will also mention that it might help if you spray regularly with a fungicide too.

In future, once a week as soon as you plant out as a preventative. This year, once a week on the remaining plants.

Daconil is a common suggestion, but spraying with Actinovate or Actinovate + EXEL LG (if you prefer organic) is another alternative.

[huntsman]

Great! Thanks!

BTW I have already lowered the misters to just above the soil level in the area of the tomatoes. Will this be fine or should I remove them altogether?

[Suze]

Originally Posted by huntsman

Great! Thanks!

BTW I have already lowered the misters to just above the soil level in the area of the tomatoes. Will this be fine or should I remove them altogether?

If you water only early in the day AND the plants (foliage) don't stay wet too long, that will certainly help.

I would also suggest a little selective pruning, mainly to take off the foliage (and any suckers) up to about a foot or so above the soil.

And do look into a weekly fungicide spray as I suggested before.

Also, if I recall correctly, you mentioned some problems with spider mites last year? If that was you, the best approach is to prevent before you see any signs of damage. Just a friendly reminder, if so.

Like you, I have to worry about everything mentioned above in my southern climate.