New growths are black on my Den. Bracteosum
 

Hi everyone,

I have a Den. Bracteosum that's pushing out new growths with leaves that emerge black from the top of the growing stem/cane (I hope the attached pictures illustrate). This means that all new growths stop growing after their first two or three weeks because the bit from which new leaves emerge is essentially dead even if the rest of the cane is alive.

Some of the more mature leaves also have black tips and I also have some leaves turn yellow and fall off. I know that this is not in itself anything out of the ordinary but they yellow out from a black spot (again, I hope the attached picture illustrates what I mean) and I suspect this is related to the new growth emerging black.

I have already started treating with Physan 20 about once every two to three weeks and the situation seems to have improved in that the blackening is not as severe and confined mainly to leaf tips, giving new growths a better chance to mature.

Any tips/suggestions/ideas would be most appreciated as I am so looking forward to this flowering and I hope the plant can make it to that stage in one piece.

What are your ambient temperatures and humidity? How are you watering? Dens should not even approach dryness when pushing new growth.

There are lots of reasons this can happen. Too cold temps can cause this so we need to know if temps ever drop below 20C to rule that out.
Overfertilisation can cause this but I will leave that as an unlikely possibility.
Too low light can cause this.
A wrong ph can cause this too.
Finally the easiest to check is the state of the roots, rotting roots can cause this also.

Thanks!

It's always indoors in an apartment with central heating so while the air does get dry from time to time it rarely ever falls below 20C. It sits on a western facing window sill so gets an adequate amount of lights.

I water whenever the pots feels light which amounts to about once a week. Other than that I repotted it soon after I bought the plant so can rule out root rot .
It seems to be thriving otherwise which is why I suspect it might have been a disease of some sort.

I don't think you're watering enough.

Thanks, I'll definitely up the watering as I have noticed that it dries out a lot faster than my other plants and what I figured would be an adequate amount of water was clearly not.

It's interesting though you pointed to the watering, do you think that it's just dry and therefore the leaves are burnt out or do you think the lack of watering has left it weak and therefore suspectible to disease?

That's wilting damage. Fingal/bacterial diseases are extremely uncommon unless humidity is very high, or temperatures are far outside appropriate bounds.