I could use some help with diagnosis

[ramse]

Initially, your pH went up to 7. Never allow it to go higher than 6.5 to reduce the chances
of some trace elements like iron and manganese being locked out. A range of 6.2 to 6.5 in
soil is nice. Without knowing more I would give the plants a little epsom salt, cal/mag and
a fertilizer with equal nutrients like 7-7-7 to cover all bases. Throwing a few rusty nails in
your watering reservoir in increase iron levels won't hurt. You could also try feeding some
plants more nutrients than the others to see if they recover before trying all of them.

it could be the ph... in fact the bed rests on a slab of carbonate rock and also the mix of soil is made with a percentage of native carbonate soil which is rather alkaline.
A few days ago I made a top-dress with a handful of organic pellets npk + mg-s 6 5 12 + 2 12

 

[Three Berries]

Plant some legumes as a cover crop. They lower soil pH by fixing nitrogen.

 

[troutman]

Lower the pH then.

 

[Maple_Flail]

Lower the pH then.

I second this.

 

[ramse]

I had noticed some ants around the plant, but after checking that it did not have aphids (given the mutualistic relationship that they have with them) I did not worry much...
I was wrong!
a few days ago I found the stem eaten, I immediately thought of a mouse or a vole... and nothing, I proceeded to enclose the stem with a protection. This morning I find the stem invaded by ants and I started wondering if they weren't the ones who peeled the stem. I have done some research and it appears that ants, especially fire ants, skin and nibble the bark

https://www.growingamerica.com/news/2019/08/managing-fire-ants-hemp

https://gpnmag.com/news/fire-ants-causing-early-damage-in-alabama-hemp/

https://mrec.ifas.ufl.edu/hemp-insects-and-
mites/

https://nwdistrict.ifas.ufl.edu/phag/2022/06/24/fire-ant-damage-in-hemp-identification-and-control/




regarding the damage on the stem, do you advise me to disinfect it with hydrogen peroxide and to apply some pruning/grafting wax? or do I leave it like this?

 

[ramse]

FIRE ANTS​

Fire ants (red imported fire ant, Solenopsis invicta Buren, and black imported fire ant, Solenopsis richteri Forel) are omnivorous and can eat the stem of hemp plants, causing wilting and plant collapse. They form single- and multi-queen colonies in large mounds of dirt, rotting logs, around trees, and under pavement and buildings. The queens must be killed to eliminate a colony. Individual mounds may be treated to reduce impacts to native ants. Scalding hot water (190-2120F) poured on the mounds has an elimination success rate of 20-60% and must be repeated. Extinguish Professional Fire Ant Bait is labeled for hemp in Florida, but other chemical baits not labelled for hemp must be placed outside of the production area.

I'm starting to think that the plant problems are due to these ant bastards... the war has begun

 

[Three Berries]

I got bit by fire ants the first time last week. Going though a old pile of tree chips the power company tree trimmers left this early spring. They were from Missouri and must have brought the ants in the truck as they don't survive the winter here.

But a borax/sugar paste knocks ants right out. Leave it where they can find it in a jar lid. Toxic to animals.

 

[jackspratt61]

I had noticed some ants around the plant, but after checking that it did not have aphids (given the mutualistic relationship that they have with them) I did not worry much...
I was wrong!
a few days ago I found the stem eaten, I immediately thought of a mouse or a vole... and nothing, I proceeded to enclose the stem with a protection. This morning I find the stem invaded by ants and I started wondering if they weren't the ones who peeled the stem. I have done some research and it appears that ants, especially fire ants, skin and nibble the bark

https://www.growingamerica.com/news/2019/08/managing-fire-ants-hemp

https://gpnmag.com/news/fire-ants-causing-early-damage-in-alabama-hemp/

https://mrec.ifas.ufl.edu/hemp-insects-and-
mites/

https://nwdistrict.ifas.ufl.edu/phag/2022/06/24/fire-ant-damage-in-hemp-identification-and-control/




regarding the damage on the stem, do you advise me to disinfect it with hydrogen peroxide and to apply some pruning/grafting wax? or do I leave it like this?

I think it's done. When you pull it shave down to the center of the stalk at the base.

 

[ramse]

I have already placed some spinosad-based ant baits. Already after a few hours I found the bait invaded by several ants. I really think that soon the game is over for them. I just hope they haven't caused too much root damage... or carried viruses

tomorrow I will give the plant a nice foliar based on left-handed amino acids with a little calcium nitrate and magnesium, and at the roots a microbial biostimulant.

 

[TanzanianMagic]

It is phosphorus deficiency/lockout, with some potassium lockout too.

I think the pH is in the low side, locking out mobile nutrients and showing up in the mobile nutrients the plant needs more of at this time.

 

[med4u]

One of your pics looks like pine needles
On the ground...are you growing around pine trees? Pines grow in acidic soil
4-4.5ph,this will def lock up nutes

 

[ramse]

I tested the ph. I used a colorimetric test also equipped with barium sulfate to test the soil. giving you a precise value is not so simple, but in any case it is certainly not acidic, but it goes towards alkalinity.

with regard to mulch, these are wild grass weeds, there are also some pine needles but in insignificant quantities and above all they are not mixed with the soil. the thing that pine needles acidify the soil is a bit of a gardening myth, especially when they are not incorporated into the soil.

 

[ramse]

17 june


30 june


in these days:
(to give you an idea of the size it is just over 2 meters (7 feet) high


as you can see it grew quite well until June 30th, from there it underwent a sharp slowdown in growth and started showing the foliar symptoms that I have already shown you... although I'm not sure yet, I think in all this an important part of the problem is to be attributed to the ants...

 

[med4u]

If there are no pine trees near,could they be from a pine bark mulch?thou the needles themselves cause little concern
For ph...pine bark or chips can be very toxic to annuals...your soil ph test should quickly rule this out,
I've seen termites attack root systems,
You will be able to see just under the soil at the stem base..
Here's a good read on the subject of pine
Mulch....goodluck


Pine Bark Mulch Problems

Pine Bark Mulch Problems

Pine bark mulch can increase soil acidity when used over several years, and it can use up...

homeguides.sfgate.com

 

[ramse]

If there are no pine trees near,could they be from a pine bark mulch?thou the needles themselves cause little concern
For ph...pine bark or chips can be very toxic to annuals...your soil ph test should quickly rule this out,
I've seen termites attack root systems,
You will be able to see just under the soil at the stem base..
Here's a good read on the subject of pine
Mulch....goodluck


Pine Bark Mulch Problems

Pine Bark Mulch Problems

Pine bark mulch can increase soil acidity when used over several years, and it can use up...

homeguides.sfgate.com

take a look:

http://gardening.wsu.edu/will-woody-mulch-acidify-my-soils/

https://www.gardenmyths.com/pine-needles-acidify-soil/

however, I repeat, not using needle or pine bark mulch.

 

[med4u]

Just curious...Where are the pine needles from?

 

[ramse]

Just curious...Where are the pine needles from?

where do you see the pine needles? the mulch that I use and that you see in the photos is made up of wild weeds that grow in the Mediterranean scrub. A few needles of maritime pine (pinus pinaster) also ended up in it, but we are talking about a handful, on 2 square meters of mulch. truly an insignificant amount regardless of whether or not it causes acidity... well I collected mulch, a little everywhere, during walks in the Mediterranean scrub... and it also happened to collect weeds near a pine.