10 replies to this topic

[Lysergimite]

Hello fellow explorers I apologise for advance for such a long post but I have been a been a lurker for quite a while and this sites posts have guided me through saving a quite skinny supposed T. Bridgesii I received as a gift, however recent issues have made me decide to join and seek help from some more experienced people. Recently while breaking dormancy my cactus got a firm black spot that formed on the tip I read this was due to excess sun without the cactus adjusting to it so I lowered the light levels, started to readjust it to normal sunlight and after dormancy was broken without further issue (spines were growing again) and the black spot started to callus. however now the rest of the tip of the cactus is starting to turn tan, shrink, and separate. This has only worsened over the past day and I cannot find and information about the issue . Thank you all in advance and any help is appreciated.

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[pharmer]

It's unusual but not catastrophic

 

The black spot is rot possibly from a damage, possibly an infection.

 

The separation is the odd part.

 

It might be too dry and it might be starting to mutate. Water you can fix easily. It appears to be trying to grow, the fresh green flesh just behind the dark spot looks good.

 

If it were mine I'd chop the top off and let it do what it wants. It would most likely grow two or three new pups.

 

Have you fed it since you put it in the soil?

[Boebs]

I would cut the tip off also.
That splitting looks like the rot has possibly gotten deeper inside the core.
Take off 2-3 inches, you could possibly get it to reroot then.
Check for discoloration in the vascular ring, if you see unusual color typically brown/orangeish, cut a little futher down.

Or just let it grow and see what happends.
Really only have two choices.

[Skywatcher]

With the view inside where the hole has opened being dark, and the shrinking on the top/ crown, I would be suspicious of a core issue. I know its always difficult to consider cutting unnecessarily, but if it is a core infection it will spread back down the column and cause more substantial damage.

I 100% agree with pharmer, I would cut the top off. A healthey cactus will pup with warmer growth season coming. If you do this, check the center where the vascular ring is for discolor and or any signs of rot. If there is still any there, cut a bit farther to get to solid pale green flesh....

[Boebs]

☝this guy..

[Myc]

And lastly, make an angled cut on the top. 

If you line up the cut with the areolas the resultant cut will be at an angle. 

This type of cut will allow offsets to form at each nodal point and will shed water. 

 

I also recommend applying a dusting of horticultural sulfur. It will make a scab which will fall off after the tissue has calloused. 

[Lysergimite]

Thank you all very much! Following your advice I removed about 1 inch of the tip and it revealed the beginnings of a nasty core infection! So it was cut down to healthy flesh and the cut was dusted with sulfur. He seems to be recovering well so far, once again thank you all as I probably wouldn't have caught this before it became fatal to the cactus.

[Myc]

Now all you can do is wait. And don't add water. Let the soil go dry.

[Lysergimite]

Sounds good! Dry it is, I assume to prevent further rot?

[Skywatcher]

Yes to prevent more problems.

You also want to give the fresh cut optimum conditions to form a good scar. You will see pups form at the aureoles near the top, and also possibly at the base. Glad you caught that. I have had core rot go undetected until the entire cactus collapsed. Nothing you can do at that point....

 

Welcome to Mycotopia Lysergimite.

[pharmer]

you can get the cut column to form a callous very quickly by pointing a fan at the cut.

 

the wind dries it out pdq and you've eliminated that area as a source for further infection from without