I'm wondering if anyone can identify the type of disease here, which evidently came from the jute I used to tie my plants. Does anyone know if this is bacterial or fungal? Anything typical or known about the jute?
We always used sisal at the farm and it caused no problems. I figured the jute was as good, that's what they had at the store. But it's a disaster for my plants this year. I'm only glad I didn't tie them all up at once.

Are you sure it's not a physical injury from rubbing against the stem? Is it spreading? If not, I would suspect a physical injury.

Tx brownrexx. As you can see in the pic, the effect quickly spread beyond the point of contact, so I don't think abrasion is enough to explain it.

I spent this morning reading up and google brought me some info about the sort of rots that jute itself can get. After comparing several pictures and descriptions of host range, it seems that Sclerotinia rot is the most likely candidate. This is something that commonly affects both tomato and jute. It hasn't developed to the point where cottony blobs of fungus mold are sprouting from the surface.
https://ipm.missouri.edu/MPG/2015/8/tim ... on-tomato/
Sclerotinia is already pretty common in the north. And there are rotations that help.
https://www.saskatchewan.ca/business/ag ... clerotinia

OTOH there is another fungus that affects jute stems Macrophomina phaseolina aka "Charcoal Rot", which does look similar in some pics:
https://www.padil.gov.au/maf-border/pest/image/51125
This one persists in plant matter, soil and can be seedborne as well, which is bad news. But IDK if it would survive here in outdoor soil/winter conditions.
This source says it is favored by hot dry conditions - we certainly haven't had that. Hot and humid yes it has been. Also cold and wet.
https://wiki.bugwood.org/Macrophomina_phaseolina

I will take a look for the rusty or charcoal brown discoloration when I cut the stems.
Not very confident of my ability to tell one disease from another.

These articles seem to be referring to disease in the living jute plant itself. I have a hard time believing that it would survive the manufacturing process to produce jute twine. The outside of the jute plant stem is removed in this process and possibly the remainder is exposed to chemicals.

I am still voting for physical injury due to abrasion. It seems to follow along the entire path of the twine which also lends credence to my theory. Do you have a stem that you can sacrifice and cut open to see the inside?

brownrexx wrote: ↑Mon Jul 27, 2020 10:13 am
I am still voting for physical injury due to abrasion. It seems to follow along the entire path of the twine which also lends credence to my theory. Do you have a stem that you can sacrifice and cut open to see the inside?

This is what I thought, too when I saw the pics.

Me too! If you've had a lot of wind, there would be a lot of rubbing of the jute against the stems.

I use either jute or hemp to tie up all my indeterminates and I see some Septoria around the stems, but that is in the air around here too, so I don't want to blame the string at this point. When the temps cool down a bit I will do a more thorough examination to see exactly what is going on around the strings and get back to you.

Linda

Hmmm so many votes for abrasion. It didn't seem nearly as prickly as sisal, which we used at the farm every year and no problem. Also I have two plants that seemed 'resistant' and got just a little scarring near the string. There has been no serious wind in the greenhouse, if anything the opposite is true not enough wind. I don't doubt they are overly tender cw an outdoor plant...
Well the damage is severe enough on a couple of plants that I am planning to cut them down, so I will see what is there in the stem by way of a clue.
IDK about the manufacturing process for jute. If it is really treated with chemicals then doubtful it would carry anything with. Good point.

According to this, jute is just retted in flowing water.
https://en.wikipedia.org/wiki/Jute
You would expect that anything living on the plant surface would be destroyed in the process but it is not chemically treated, that means anything in the environment such as diseases suffered by the jute, could recolonize the product. If this was a common issue though, you'd expect we would have heard something about it.

My vote is for abrasion.

It could be a chemical burn of sorts, if they did treat it, or also if they dessicated the plants prior to harvest.

brownrexx wrote: ↑Mon Jul 27, 2020 8:08 am Are you sure it's not a physical injury from rubbing against the stem? Is it spreading? If not, I would suspect a physical injury.

This is exactly what I think it is.

Here is my take on it from a scientific point of view.
Look at it as a bad fitting new boot.
It rubs in a small spot but the spot becomes bigger.
I had this nightmare happen to me once and I had no way out of it but duct tape because I was hundreds of miles from nowhere in Alaska.
Worst two weeks of my life.
From an evolutionary point of view humans and plants are kinfolks.

Could you locate a healthy tomato stem somewhere on the plant and just twirl jute around it and let the ends hang free?
That would test your theory to see if the contact with the jute itself is causing a disease issue. If it is OK then you’ll know it was abrasion
from the plant moving against the jute.

Well, I got email back from my friend at the farm this morning - she used the same stuff and had no problem with her plants. The environment there is different than my greenhouse - the plants are exposed to more of the cold temperature extremes, more wind, but not as much bright sunlight in the plastic tunnel. My plants grow too tall too fast in general, in the greenhouse environment. The stems and the leaves, especially some varieties, become super tender under those circumstances. It's amazing how tough the leaves get when you put them outdoors, and the plants after a couple weeks look completely different. They also grow much shorter internodes etc.

So tx all of you for the good (and unanimous!) advice, I will put it down to abrasion of tender stems. Whatever fungus has got into it, I will assume it's the usual suspects and not some wierd tropical thing. Found a spot on a leaf this foggy morning, looking like grey mold. I did some cutting back today, just the excess of the new stems on top of the worst plants, and see if I can get them to ripen a few fruits they already have. And I started a new compost pile where the tomato waste will go and be properly covered to rot in peace.

My friend has offered me copper spray - what do you pros of spraying think? Would this stop the decaying of the stems? Is there anything else in the organic ballpark that could be applied to the sick stems to get them to heal? Even if I can stop them from sporulating that would be helpful, otherwise it's going to affect everything else.... My own experience is that the best remedy is ruthless removal of all such damaged stems. Still on the fence but willing to try something for a short extension of their lives...

Bower, those photos show no fungus or bacteria in the abraided areas. You dont need to treat them organically or otherwise. Just remove the jute. The stems should scar over and heal. Copper is fine for the grey mold. Use at half if the weakest recommended dose. Still plenty strong enough to do the job.

Sounds like everyone is right about the abrasion, but I'll tell you why I strongly believe it's happening to your plants and not to your friend's:

The plants have too little available potassium and/or too much nitrogen. Adding a dose of potassium sulfate (by itself) should toughen them up dramatically within two days of application, regardless of which one is true. If you just add like 10-10-21 fertilizer, or something, it won't do the same thing, at all, if my experience of using commercially pre-mixed fertilizers is indicative. I don't know why, but I've never found one with potassium that works much, even if they contain the same forms of potassium I use separately with success. You don't need to repeat the dose often. It should last a while, but then you have big plants, and I've normally ever used it on small plants; so, they might need more. You can tell when it's running out if the plants are getting tender again, though. So, there's no guessing here.

Tenderness or breakage doesn't necessarily mean a plant is deficient (although deficient plants will be tender and/or breakable), but if you want toughness and no breakage, adding potassium sulfate should reliably help. If you use it, remember that it'll make the plants thirstier for two or three days.

If you want shorter internodes, more sunlight is probably the healthiest way to get them. Other ways include limiting phosphorus, or having cold temperatures.