Why my Arisaema new shoot rot?

[yijiawang]

Hello, any one can give me some advise  for my Arisaema new shoot rotted?
I grow the bulb in nice drain soil, 50% perlite and 50% peat, mulch with 5-10cm half rotten leaves, the half rotten leaved lead to new shoot rotted?
Thank you for help in advance!

[Pascal B]

Hard to say, the rot seems fungal and not bacterial. If the rot finds its origin within the tuber generally on the side of the rot the roots grow poorly or not al all but as the root developement seems fine all I can think of is that the shoot was damaged or bruised. Try to clean up the central area where the shoot was attached and apply a fungicide (or cinnamon) before replanting. By the look of the roots and tuber I assume it is a member of section Franchetiana? Candidissimum or franchetianum?. If so most likely one or more of the secondary buds will take over as long as the rot has not expanded inside the tuber.

[Lesley Cox]

Pascal, does cinnamon act as a fungicide in those circumstances?

[yijiawang]

Thank you very much, I think my mistake is :
mulched too heavy rot leaves, the leaves keep moist on soil surface, lead to the root did not grow deep , and new shoot get too many wet, and then caught by fungi.
To Pascal, Thank you for help, you are right, the big bulb is not rot totally, 2 new noses will be grow up soon. I have clean the rotted tissue and use fungicide , hope it can survive.
I do not familiar to Arisaema genus, purchased it in medicine market in year 2008, this is bloom in the last year.
 

[Pascal B]

Pascal, does cinnamon act as a fungicide in those circumstances?

Lesley, it does. The use of cinnanmon is common practise in the orchid world for putting on cuttings but I use it more and more with my Arisaema. Some fungicides cause leaf discoloration or have other nasty effects and whenever I can refrain from using chemicals I do. Cinnamon also has the added advantage that it let's the wound cure better, it seals of the wound and somehow promotes formation of scar tissue better than chemical fungicides. Nowadays I buy half a kilo bags at the local Asian foodstore. It is a lot cheaper too than the chemical stuff!

But it only works with fungal diseases, not with bacterial infections. Bacterial infections in Arisaema are much more difficult to combat and are often more advanced than is visible. With fungal infections one can cut out the bad parts upto healthy tissue and desinfect. Bacterial infections can only be cured if noticed at an early stage and the only way to desinfect then is to use either a solution of common house bleach or hydrogen peroxide and more infected tissue needs to be cut out than visible resulting in a smaller tuber and bigger wound. Bacterial infections also spread more rapidly and destroy a tuber much faster than a fungus. Once you have smelled a bacterial infection in Arisaema, you will recognise it immediately next time but fortunately bacterial infections are rare and usually only occur in new imports.

[Pascal B]

Thank you very much, I think my mistake is :
mulched too heavy rot leaves, the leaves keep moist on soil surface, lead to the root did not grow deep , and new shoot get too many wet, and then caught by fungi.
To Pascal, Thank you for help, you are right, the big bulb is not rot totally, 2 new noses will be grow up soon. I have clean the rotted tissue and use fungicide , hope it can survive.
I do not familiar to Arisaema genus, purchased it in medicine market in year 2008, this is bloom in the last year.
 

Yep, that is a form of Arisaema franchetianum. Most likely the tuber will fall apart in separate clusters at the end of the season. Although not your intention, it is one of the ways to increase Arisaema: cut out the apical shoot so the dormant sideshoots/bulblets take over. But members of that section are prolific anyway usually producting upto 6-8 pups each year that will produce new growth the next year, something not all Arisaema do. Many species produce bulblets that need an additional year in the soil before they produce their first shoot.

[Lesley Cox]

Thanks for that Pascal. Cinnamon has the added advantage of smelling nice too.

[bulborum]

Pascal

how do you use cinnamon
do you mix it in the soil or you just powder the wound

Roland

[Pascal B]

Roland,

I powder the wound because that's the place where it is needed, you can mix it in the soil as well if you like the smell......;-)