Mystery ailment killing Trithrinax acanthocoma

[Marius]

Hi everyone. 
One of my Trithrinax acanthocoma which was growing well and rather fast has recently declined fast and I am at a loss as to the reason. 
At the end of January ( hottest time of year here) the leaves drooped and started to dry out ( no yellowing). Since then it has become worse and now the new spears are drying out as well. The other two ( smaller ones) are unaffected. 
 

Is there anyone here who has an idea of what could have caused it?

Below are pictures of it before the decline. 

[Marius]

The sudden decline:

 

[Marius]

It looked like a transplanted palm. I noticed ant nests. Poisoned those. 
I increased watering. 
 

[Marius]

This is it today. I threw hydrogen peroxide into its crown today. 

[richnorm]

Ouch, sad to see.  I think it maybe was just an unlucky infection in the growing point that happens sometimes.  

[Marius]

11 hours ago, richnorm said:

Ouch, sad to see.  I think it maybe was just an unlucky infection in the growing point that happens sometimes.  

Thanks. I hope that it doesn’t spread to other palms. 

[Phoenikakias]

22 hours ago, Marius said:

It looked like a transplanted palm. I noticed ant nests. Poisoned those. 
I increased watering. 
 

Probably it won't help, makes things only worse.  Typical symptoms of root or basal stem infection. As to the reasons... something had caused weakening of plant's immune system, like lack of water, or soil salinity (included increase of salt content through use of chemical fertilizers).

[Phoenikakias]

I suspect thielaviopsis, I have lost this way several south American palms (Parajubaea, Acrocomia,  Jubaea), pattern of decline was identical. It will spread also to other plants, if you do not take preemptive action. A biological treatment with Trichoderma strains  is imo necessary.

 

[happypalms]

Not a good outcome for such a beautiful. On the bright side of it I just germinated 6 of them so they  live on in Australia now.

[Mazat]

4 hours ago, happypalms said:

Kein gutes Ergebnis für so eine schöne Pflanze. Das Positive daran ist, dass ich gerade sechs davon zum Keimen gebracht habe, sodass sie jetzt in Australien weiterleben.

yes, that's how it should always be and your news makes me and Sabine happy. unfortunately, an ensete venricosum maurelii died on me, even though it survived last year's much harsher winter and the one before that ... we simply have no luck with this species, neither indoors nor protected on the balcony ... makes us sad ...
 

[happypalms]

6 hours ago, Mazat said:

yes, that's how it should always be and your news makes me and Sabine happy. unfortunately, an ensete venricosum maurelii died on me, even though it survived last year's much harsher winter and the one before that ... we simply have no luck with this species, neither indoors nor protected on the balcony ... makes us sad ...
 

Yes keeping the species alive no matter where it is an important thing for the future generations. If a plant is lost in the wild at least we know it is in cultivation for the future of the planet some palms just due and it baffles the grower as to what it is that killed them. You’re ensete is one such example, I have some species of be palms that die no matter what I do, the climate is just simply wrong for that palm too hot or cold soil rainfall lots of environmental factors stop a palm dead in its tracks so to speak. 

[Merlyn]

@Marius the sudden canopy collapse makes me think of a root or lower trunk rot, not anything at the growing point.  The crown fronds flopping over looks like a loss of hydrostatic pressure.  If it can't bring in water from the roots, or can't transport water up the trunk to the fronds then they won't stay upright.  I have seen this in potted palms and cycads that had rooted through the pot and into the ground.  

My guess from photos is that it is already dead, and if you dig it out you'll find lower trunk or root rot.

[Marius]

Thanks for all the feedback. It is much appreciated.  I think that @Phoenikakias and @Merlyn hit the nail on the head. I was away for a week in January when it was extremely hot and I think that the house sitter didn’t get to water where it is. 

[Mazat]

On 3/16/2025 at 6:08 PM, Marius said:

Thanks for all the feedback. It is much appreciated.  I think that @Phoenikakias and @Merlyn hit the nail on the head. I was away for a week in January when it was extremely hot and I think that the house sitter didn’t get to water where it is. 

We planted a CIDP in May 2019 and had full protection, but in February 2022 we had a storm with short-term warming of the air, in some cases up to +10 °C / +50 degrees fahrenheit due to the Föhn wind (The Föhn or Föhn wind is a warm, dry downslope wind that often occurs on the side facing away from the wind direction - the leeward side - of larger mountains. It usually occurs over a large area in weather conditions with pressure gradients across the mountains. It can blow steadily, but can also be gusty).
The whole protection was completely damaged and 2 days later a cold front set in and the temperature dropped to -9.5 °C / 14.9 degrees fahrenheit. we were away for a few days and when we came back she was completely frozen at heart and all the fronds were bent. it was a sad sight. Healthy she was about 2.5 m / 8ft 2inch high.  

it was a gift from an elderly but very fit lady who was 85 years old at the time and she had the plant in a big pot and she thought we could manage with all the protection ...

you're away once and then something like this happens. we can sympathize with you.

 

[Merlyn]

@Marius out of curiosity, what kind of temperatures did you see when it may not have been watered?  In my area established palms have hit the water table, which is only about 5-6 feet down.  So except for recent plantings or transplants, many of my palms don't even need to be watered.  I still think it's a "loss of hydrostatic pressure" that caused the crown to collapse, but I'd be surprised if a week without water would have caused that in clay soil.  Of course, if it was really hot and dry at the same time then that seems more possible.  I live in a hot swamp so my perspective is...er...somewhat skewed.   

[Tyrone]

Marius, do you have cracking clay soil there that shrinks when it’s hot and dry. Sometimes that sort of clay can literally rip roots apart underground as it shrinks. Not a problem for plants that don’t mind a bit of root disturbance but a species that can’t handle that it could be fatal. I’m not sure on whether this species can handle that. 

[Marius]

7 hours ago, Mazat said:

We planted a CIDP in May 2019 and had full protection, but in February 2022 we had a storm with short-term warming of the air, in some cases up to +10 °C / +50 degrees fahrenheit due to the Föhn wind (The Föhn or Föhn wind is a warm, dry downslope wind that often occurs on the side facing away from the wind direction - the leeward side - of larger mountains. It usually occurs over a large area in weather conditions with pressure gradients across the mountains. It can blow steadily, but can also be gusty).
The whole protection was completely damaged and 2 days later a cold front set in and the temperature dropped to -9.5 °C / 14.9 degrees fahrenheit. we were away for a few days and when we came back she was completely frozen at heart and all the fronds were bent. it was a sad sight. Healthy she was about 2.5 m / 8ft 2inch high.  

it was a gift from an elderly but very fit lady who was 85 years old at the time and she had the plant in a big pot and she thought we could manage with all the protection ...

you're away once and then something like this happens. we can sympathize with you.

 

Thank you @Mazat 

[Marius]

7 hours ago, Merlyn said:

@Marius out of curiosity, what kind of temperatures did you see when it may not have been watered?  In my area established palms have hit the water table, which is only about 5-6 feet down.  So except for recent plantings or transplants, many of my palms don't even need to be watered.  I still think it's a "loss of hydrostatic pressure" that caused the crown to collapse, but I'd be surprised if a week without water would have caused that in clay soil.  Of course, if it was really hot and dry at the same time then that seems more possible.  I live in a hot swamp so my perspective is...er...somewhat skewed.   

We had between 32 to 36 deg C. 

[Marius]

4 hours ago, Tyrone said:

Marius, do you have cracking clay soil there that shrinks when it’s hot and dry. Sometimes that sort of clay can literally rip roots apart underground as it shrinks. Not a problem for plants that don’t mind a bit of root disturbance but a species that can’t handle that it could be fatal. I’m not sure on whether this species can handle that. 

No. The soil is not bad. It is a clayish loam. 

[Phoenikakias]

2 hours ago, Marius said:

We had between 32 to 36 deg C. 

This is hot, but in the mid range. What is the soil pH like? 

[Marius]

9 hours ago, Phoenikakias said:

This is hot, but in the mid range. What is the soil pH like? 

Not sure about pH of soil. I assume that it is alkaline as we have lime in our ground water. 

[Phoenikakias]

1 hour ago, Marius said:

Not sure about pH of soil. I assume that it is alkaline as we have lime in our ground water. 

Have you applied during the previous time any fertilizer? I have alkaline soil (around 7.5) and alkaline water (above 8 ) too, and my Trithrinax acanthocoma around the end of each local summer (mid to late August) used to soften slightly its blades, obviously an indication of water uptake block (because I irrigate regularly). That had signaled finally an alarm to my mind and last year I applied trichoderma, sulfur pellets and only compost instead of the usual chemical crf. It fared this way much better all summer long. Bear in mind that T acanthocoma comes from Brazil, as almost all Butia spp, Syagrus, Allagoptera. All these spp prefer acidic soil together with Jubaea, Parajubaea, Acrocomia and demand that alkalinity does not exceed a critical point. Otherwise such plants would become weak and open to fungal infection. I lost during the previous years to fungal infection with identical symptoms one Jubaea, two Parajubaea and two Acrocomia. And nearly lost also two Allagoptera.