Hard, Dark growth on Achuma Cactus

[fortezozo]

To start, this is not the first time I have experienced this ailment. The first time only affected one rib on the tip of a cactus, I erroneously considered it rot and cut the rib out. The cactus grew in nice and healthy.

The next time I found this growth (on a second cactus), I sat back to see if it was just benign scarring and scabbing. The growth spread throughout the tip of the cactus and seemed to prevent new growth from forming. I ended up having to cut the whole tip off.

So, here I am with another cactus afflicted and I still have no clue as to what the ailment is or what preventative measures include. It spread from one rib to nearly all of them in a day. These are the latest photos of it and here is what I know:

- It is hard, rough and scab-like
- It seems to replace the waxy skin
- It seems to only appear on new growth (tips and pups)
- It only has afflicted the Achuma (have yet to see anything like it on San Pedro)
- It will continue to spread

Possible triggers may be over fertilization and over watering (this is speculation). Google searching did me no good in finding a name or cause.

I hope that there is something I am overlooking which can shed light on this problem and possibly prevent unnecessary cutting of my friends.

[Frequency]

Hmm, looks like standard rot to me..

[real_psily]

I have had the same problem.
Also, only with achuma.
It also only happens to ones that are potted.
I believe it is tip rot due to over watering. I have not put fert down on the ones that have had the "rot" so it shouldn't be an over fert problem.
I noticed that it seemed to stop progressing through the cactus if the soil dried out very well.
This is still all a guess with observations.
I would love for some clear info on this also.
Hopefully one of our resident cactiphiles will gives us some good info.

[fortezozo]

Sorry for the delayed response, life issues.

After thinking about it for a bit I, too, have concluded that it is a form of rot (which is quite the blanket affliction). This is a bacterial infection.

"Weeping black rot" seems to be what people generally call it. There is a lot of debate whether it should be removed or left in nature's hands (with ceased watering).

I had ended up removing most of the rot with a steralized razor and stopped watering the cactus. Since then, the tip is recovering nicely (although the missed rot has malformed some of its growth). Additionally, a third now fourth pup have popped up.

Could this pupping be an answer to the stress of being cut and having restricted tip growth?

[Ferretious]

Yes, definately. When a growing tip dies or is cut off almost any plant will start a new tip or more somewhere else.
Ferretious

[fortezozo]

Well, the tip was not completely removed. It has even begun recovery. Its growth is skewed thanks to the rot but the removed parts grew in just scarred.

The new little pup is coming up between the back left and front one. You can see the front one recovered on its own, which is great .

[Irishlion]

has it been raining alot there, or you been watering them more than once or twice a month?

[fortezozo]

There was a streak of afternoon thunderstorms for a week or so. Most of them missed us while a light shower here and there got through. I think the high humidity got to them.

I ended up moving them in for nights and for every shower that came by.

Another thing I noticed while moving them out in the morning was damp spots where some were sitting. A sign of poorly draining soil?

That reminds me, people suggest using perlite in the soil mix to keep it airy, right? Don't they also use it in fruiting chambers to humidify the air?

[Irishlion]

Originally Posted by fortezozo

There was a streak of afternoon thunderstorms for a week or so. Most of them missed us while a light shower here and there got through. I think the high humidity got to them.

I ended up moving them in for nights and for every shower that came by.

Another thing I noticed while moving them out in the morning was damp spots where some were sitting. A sign of poorly draining soil?

That reminds me, people suggest using perlite in the soil mix to keep it airy, right? Don't they also use it in fruiting chambers to humidify the air?

Take, and slightly dig down into that soil, about say 3 to 4 inches, and see if its damp or wet if it is then your soil isn't draining properly and you might wanna add some course grade sand or aquarium gravel to it to help with the drainage

[fortezozo]

Originally Posted by Irishlion

Take, and slightly dig down into that soil, about say 3 to 4 inches, and see if its damp or wet if it is then your soil isn't draining properly and you might wanna add some course grade sand or aquarium gravel to it to help with the drainage

It is dry. I can only get about 2 inches down before disturbing roots.

What would you suggest for pot shape? Wider or deeper?

Thanks for the help

[real_psily]

IrishLion,
What do you think about using styrofoam chips or pea gravel as a soil amendment?
Both are very easy to find and super cheap.

[Irishlion]

Originally Posted by fortezozo

It is dry. I can only get about 2 inches down before disturbing roots.

What would you suggest for pot shape? Wider or deeper?

Thanks for the help

If you are digging down on the sides of the pot and you are finding roots, you need to upgrade you pot size, bigger deeper and make a better draining soil. a good mix is 1/3 cactus soil, 1/3 aquaroium gravel and one 1/3 perlite with a layer of gravel approx 1 inch deep on the bottom of the pot.

You will however have to remove the rot, before it spreads to the rest of the cactus.

[fortezozo]

Originally Posted by Irishlion

If you are digging down on the sides of the pot and you are finding roots, you need to upgrade you pot size, bigger deeper and make a better draining soil. a good mix is 1/3 cactus soil, 1/3 aquaroium gravel and one 1/3 perlite with a layer of gravel approx 1 inch deep on the bottom of the pot.

You will however have to remove the rot, before it spreads to the rest of the cactus.

Sounds like a plan.

Are you a fan of porous clay pots, or some form of plastic for potting container? I read that minerals tend to deposit on the inside walls of porous pots and can lead to root damage. But, on the other hand, the plastic may not drain as efficiently.

[Irishlion]

Originally Posted by fortezozo

Sounds like a plan.

Are you a fan of porous clay pots, or some form of plastic for potting material? I read that minerals tend to deposit on the inside walls of porous pots and can lead to root damage. But, on the other hand, the plastic may not drain as efficiently.

clay all the way.