Diseased leaves

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Diseased leaves

#1

Post: # 73505Unread post Labradors
Sun Jul 10, 2022 10:40 am

Any ideas on these diseased leaves?

These are high up on two of my four Sweet Baby Jades, growing in containers on my deck. They have been thriving, and I've been watering them twice a day.

I only just noticed this, despite checking on every time I walk past them!

Thanks for any insight.

Linda
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Re: Diseased leaves

#2

Post: # 73548Unread post bower
Sun Jul 10, 2022 6:28 pm

How's your weather this summer?
Could this be a sunburn or wind burn effect? Being close to the top.
We had a night of rain and both plants from my Yellow Project got purplish streaks, that is typical of hot weather mildews of tomato. And none of the others had any, so it can be all about susceptibility.
Those leaves look more like a botrytis type mold, being brown - that is out of the small number of diseases I personally have met and had to deal with.
It does look like the affected areas could be places that collected dew or rain and a fungus decided to make it home.
I always expect diseases to spread so take away asap, but it's not always a clear win when your top leaves are affected, as then the fruit have no protection from sunburn. So sad to see top leaves in a bad way.
I have had some susceptible plants get a pinky brown mold, similar shade, in the summer, and it spread to their stems and to other plants too. I still don't know what it was. Maybe Alternaria, except I expect to see some yellow with that. You have the really defined lines, that is typical of Alternaria.
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Re: Diseased leaves

#3

Post: # 73584Unread post Labradors
Mon Jul 11, 2022 6:30 am

Many thanks for your help Bower :).
The weather here has been hot (with cool nights) and I drag the pots under the awning whenever rain is in the forecast (just to lesson the chance of mold on the leaves), but they are still subject to dew and the grass has been wet in the mornings recently so we've had lots of that. I didn't mention that some of the lower leaves have had dark (purplish) areas on them for a long time.

I have dealt with botrytis before (in the garden). It affected the stems which I reluctantly removed which, thankfully, that saved the plant.

I just looked at the leaves under the magnifying glass and don't see any obvious signs of mold, but this is widespread on one of the plants now so I'm going to have to take some drastic action.

Linda

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Re: Diseased leaves

#4

Post: # 73600Unread post bower
Mon Jul 11, 2022 11:35 am

Well I went into the greenhouse to water this morning and, what do you know? Same as you! Or pretty darn close. Just on one plant; upper leaves closest to the greenhouse wall and glazing. Same pattern of browning, same shade of brown, but I couldn't see much of a defining line around the areas, which could just be the leaf type or variety effect or the fact it was very brand new.
We are having the same weather exactly, hot days and dewy cool nights. Actually, pretty low dewpoints in the daytime for the past couple days, a little chill on the breeze while blazing sun and blue skies. Also we're both growing in containers, and that means as you mentioned, lots of watering in hot weather.
Maybe there are nutrient deficiencies involved? Potassium deficit is said to cause brown spots on leaves, while magnesium deficiency could be involved in the "purple". I know it seems like dew and sun exposure is positively a cause, but maybe some feeding would help?
I've been wondering if i should give them some liquid ferts in the evening, vs I always water them in the morning.
With regards the leaf purpling, I've always believed it was some kind of mildew, and I always see it in the hottest and most humid part of the summer, never at other times. I have two plants outdoors this year that all the lower leaves purpled overnight during a night of rain. None of the others in the same row were affected.
But maybe there's a link between the physical conditions and the plant's access to those nutrients?
Sorry not to be more informed about this. It's a problem worth solving.
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Re: Diseased leaves

#5

Post: # 73617Unread post Labradors
Mon Jul 11, 2022 4:17 pm

Sorry to hear that your plant is suffering too, but it's comforting to know that I'm not alone.

I couldn't bring myself to remove the leaves.

I fertilized a few weeks ago now, so they are probably in need of some more now. Good idea!

Is your plant PL too?

Linda

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Re: Diseased leaves

#6

Post: # 73625Unread post bower
Mon Jul 11, 2022 6:16 pm

Not a PL.
Actually by this afternoon there was a bit of browning on the leaves right along that side, so multiple plants affected.
I didn't remove them for now as they are mostly small defects. But I did do the rounds on lower leaves and there's a bit of spotting here and there, I do suspect Alternaria. Couple of the plants had classic yellow in the leaf spot, others were more brown, and I believe that may be because Alternaria blight looks different in the hottest part of summer.
Still not sure, but I'm pretty sure the plants could do with some ferts, if I could just make up my mind and do it.
Think I should pick up a bag of compost to top dress, some of them are in pretty small pots and some roots showing.
In other news two fruit blushing today :D Finally the beginning...
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Re: Diseased leaves

#7

Post: # 73628Unread post Shule
Mon Jul 11, 2022 6:25 pm

Some viruses, toxicities, and deficiencies look *similar* to that, but other than the bronzing, it reminds me more of how our potted Northern Catalpa tree without drainage looks when we overwater it, or when it gets fertilizer burn. Don't ask me why it doesn't have drainage (I just realized the fact on Saturday, I think).

Did you happen to overwater, overfertilize, get some chemicals on it, or something?

Watering two times a day does sound like a lot, unless you've got a small container, or unless it dries out really fast.
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Re: Diseased leaves

#8

Post: # 73671Unread post Labradors
Tue Jul 12, 2022 6:50 am

Bower, the browning has spread, but I'm not seeing any yellow on the leaves here.

Shule, I didn't overfertilze or get chemicals on the leaves. I have a Maglia Rosa in the same size container, and she is a drama queen and tells me when she needs more water so I give them all a drink. I tend to under-water my pots and water rarely exits the drain holes.

I'm beginning to get some blushing fruit :).

Linda

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Re: Diseased leaves

#9

Post: # 73688Unread post MissS
Tue Jul 12, 2022 11:38 am

It sure looks like Alternaria Canker to me. It's a fungal disease remove infected leaves and treat wit a fungicide. Clean up all debris from the ground.
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Re: Diseased leaves

#10

Post: # 73694Unread post Labradors
Tue Jul 12, 2022 12:55 pm

It does look a bit like altenaria Miss S, but I think I've found the answer and it's lack of magnesium! Bower was right the first time! The purpling was the giveaway and I didn't think that was anything to worry about. Will add some Epsom salts.

https://www.helpfulgardener.com/forum/v ... hp?t=69800

Linda

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Re: Diseased leaves

#11

Post: # 73696Unread post Labradors
Tue Jul 12, 2022 1:45 pm

Duplicate post. Sorry.

Linda
Last edited by Labradors on Wed Jul 13, 2022 8:01 am, edited 1 time in total.

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Re: Diseased leaves

#12

Post: # 73735Unread post Shule
Wed Jul 13, 2022 12:24 am

That's interesting. I didn't know magnesium-deficiency could manifest with purple (I've been calling that a bronzed look). Some things still look unique about this to me, though. I mean, the veins are bleeding out into the rest of the leaf; I wonder what's causing that (or maybe that's just the unaffected/uncrispy parts of the leaf).

If Epsom salt gets rid of the problem entirely, feel free to let us know! :)
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Re: Diseased leaves

#13

Post: # 73757Unread post bower
Wed Jul 13, 2022 6:45 am

It's also true that many diseases of tomatoes seem to manifest as an effect on their nutrient status, and symptoms can look the same.
@MissS I will read up on "Alternaria canker" because that is, I believe, related but not the same as EB, but could explain the spots I'm seeing and the stem attacks which I've seen in similar weather conditions before.
OTOH I'm also taking a proactive approach to the nutrient status questions this time. Still mulling exactly what to feed. It is certainly worth noting that we are both getting these symptoms just when fruit are beginning to blush. The need for a boost to resist disease as fruit ripen is classic.

Here is a link:
https://www2.ipm.ucanr.edu/agriculture/ ... em-Canker/
Copper fungicide and garlic extract at 10% were most effective controls in this study, which is about foliar treatments not nutritional status:
https://www.researchgate.net/publicatio ... _Alternata
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Re: Diseased leaves

#14

Post: # 73765Unread post Labradors
Wed Jul 13, 2022 8:10 am

Bower, I had stem attacks early in the season on one Blush, planted in the garden. It was very nasty, affecting stems at the top of the plant and causing the young suckers to die. I concluded that it was Pith Necrosis, and read somewhere that, because it works its way from the top down, the plant could be saved by removing all the diseased stems. I did that, removing most of the plant, and ended up with just one sucker that was disease-free. The plant is now growing well.

You are absolutely correct that our plants are both in pots and both blushing. The magnesium deficiency (purpling) hasn't been a problem until now. I should add that I used some old Promix from last season, amended with aged chicken manure compost. Someone commented in that link that I shared, that chicken manure doesn't break down well in a container!

I'm going to try and find some soluble Pro-mix and give these plants a good feed with that since they are so darned picky about my home-made organic ferts!

Linda

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Re: Diseased leaves

#15

Post: # 73771Unread post mama_lor
Wed Jul 13, 2022 9:54 am

Shule wrote: Wed Jul 13, 2022 12:24 am That's interesting. I didn't know magnesium-deficiency could manifest with purple (I've been calling that a bronzed look).
Mg definitely gives a purple tinge around necrotic internodal chlorosis. More visible on some varieties. Not sure about those leaves though, there's probably Mg, but some other problem as well. Such direct browning and drying is really atypical for Mg, I battle it every year but never seen it like this. If it's a disease or nutrition problem, tough to say.

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Re: Diseased leaves

#16

Post: # 73788Unread post bower
Wed Jul 13, 2022 12:30 pm

Well it's worth considering whether more than one thing is happening at the same time.
With regards fruit ripening and nutritional status, it is typical for a plant that's short of nitrogen to withdraw it from the less useful lower leaves. Then you get yellowing and/or disease below which has to be removed. It can be stopped by feeding the plants.
The other thing about that life stage for tomatoes, when they withdraw N from their leaves they also withdraw immune support. So what I typically have observed is that when a plant is scavenging N from lower leaves, those leaves get whatever disease the plant is most susceptible to. Early Blight, Botrytis mold, are the typical ones in my climate and associated with cold wet environment or microenvironment.

This other disease or condition, or set of conditions in hot and humid weather is not the same thing. The Alternaria Canker and Alternaria "Early Blight" look different and have different lifestyles, even though they are cousins. We are seeing some upper leaves affected, which could also be physiological damage due to lensing of dew in hot sun and high UV. All of the leaf damage in my greenhouse was entirely on the sun side of the canopy where the effects of the fan are only indirect, vs the Early Blight when present is generally starting on shaded leaves. OTOH I'm now thinking about the other problem I have seen a couple of times in hot weather, that is very probably Alternaria canker, which attacked stems and affected some fruit as well - I don't think I paid attention to the leaves or considered them part of the same problem. So I really am not sure if these leaves are part of that, but just on the chances that it is the same and starting on the leaves, I cleaned them up entirely this morning just in case they might be getting ready to drop spores onto the stems and fruit. Not worth taking a chance on it.

I read a paper from India where Alternaria alternata aka the Canker is becoming more of a problem under climate change. Hotter, more humid conditions, plants under heat stress, and it is flourishing there and causing crop losses. They have been researching some natural substances to treat the disease.
Various authors suggest that growing resistant plants is the key. Certainly I think there must be a lot of natural resistance in what I'm growing, partly because I will not repeat a variety that gets stricken with Alternaria canker. It's very nasty on stems. And the year I grew Orange Minsk, it was on every fruit. Not even a single good fruit for seeds on that plant.

Anyway, there is a simple solution if worth the effort. According to several researchers, Systemic Acquired Resistance to Alternaria canker can be induced in susceptible or exposed plants with salicylates. Works whether applied to leaves by spray or fed to roots.

https://profdoc.um.ac.ir/paper-abstract-1017995.html
Exogenous Applications of Salicylic Acid for Inducing Systemic Acquired Resistance against Tomato Stem Canker disease.
Applied to leaves.

https://apsjournals.apsnet.org/doi/abs/ ... 9.89.9.722
Root feeding 200 micromolar SA can significantly elevate foliar SA levels, induce PR-1B gene expression, and activate systemic acquired resistance that is effective against A. solani.

natural source: willow, poplar and birch have similar levels of salicylates on the order of 3-10% in bark and leaves
https://ndnr.com/pain-medicine/salicyla ... nd-betula/

Salicylates are not destroyed by boiling so it's easy enough to extract from leaves with a little simmering and steeping.
I am just brewing up some birch leaf tea, which I hope will be strong enough without cooking on the stove. To go with other plant treats when it has steeped and cooled.
Or you could try an aspirin @Labradors for the same effect. I don't have one in the house, so going for the leaf extract.
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Re: Diseased leaves

#17

Post: # 73799Unread post Labradors
Wed Jul 13, 2022 2:06 pm

Bower, I've just bought some soluble Promix fertilizer, and will dose all my potted tomato plants with that. Aspirin is a great idea! I never use it for myself, but saved any old bottles that were kicking around when I read that it helps with plant immunity. I even went as far as buying dissolvable aspirin for that purpose, but couldn't really tell whether or not it was helpful at the time.

Linda

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Re: Diseased leaves

#18

Post: # 73842Unread post bower
Thu Jul 14, 2022 6:14 am

I did feed mine as well, did a top dressing yesterday evening with a bit of kelp meal and a few chicken pellets all covered with fresh compost. Will be straining the birch brew to add to their watering this morning.
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