Pleione overwintering problem

[mickeymuc]

Hi,

And a happy new year to everyone!
On some Pleiones I have losses during the winter, the pseudobulbs develop brown and dry spots, sometimes die or at least start qiute wakly into the new season. Others are unaffected. They are overwintered very cool (2 to 8 degrees estimated) in our garage. Could humidity being too high cause this problem? Or is it something known to others? To be sure I dipped all bulbs with neem oil (as I didn't do that in autumn) and cinnamon to help with possible fungus infaction. I wonder of I shold give them a drier place? Please don't be irritated by the pic, this was taken just after soaking the bulb in neem so it is all wet. Usually they are dry, but humidity is not very low there, as the wet or snowy car goes in there.

Thanks ffor any hint !

All the best,

Michael

[Maren]

Hello Michael,

I am sorry to have to say this but I wouldn't keep a pleione that looks like that. The lesions are likely to spread and, depending on what caused them, probably a fungal infection, this may also spread to your other pleione pseudobulbs.

When I started with pleiones, I kept everything, no matter how it looked, hoping that it would get better. That was a mistake. I soon learnt from Ian Butterfield, to get rid of anything that looked in the slightest bit diseased or damaged. In that way, one's collection gets better from year to year.

The important aspects are hygiene i.e. annual re-potting and selection i.e. discarding anything that could cause a problem. And of course one has to observe correct culture. If your bulb looked like that when you took it out of its pot in the autumn, then you kept it too wet and too cold after it stopped growing. Cold (above freezing) is OK, but wet and cold is not. - Better luck next year.

[mickeymuc]

Hello Maren,

Thank you for your Message and advice! This bulb did not look like that when I too it out of the pot, this thing (probably a fungus) developed during winter, the bulb looked fine when I took it out of the pot.
If it was a bulb I can easily get again I'd agree to discard it, but as it is one I have only very few I'd rather keep it, though at a separate place. This one is Burnsall, not too exotic but I don't know where to get it. I treated it with a fungicide and hope this will help - possibly I'll still have to learn to throw plants away  .
I think I'll move the rest of the bulbs to a drier place, fortunately most of them look very good, so I think there'll be plenty of flowers next year, despite some possible losses...

p.s. Maren, do you use any kind of fungicide on your Pleiones? I know some people do, and possibly I should use one at least for one or two seasons....

[Maren]

Hi Michael,

sorry about your P. Burnsall, I have some but too few to sell. Maybe when they have multiplied, I can let you have one.

I use Roseclear once in January and in February , but I don't think I need it because in my storage I control temperature, ventilation and humidity. In November /  December, when I oil the pseudobulbs, humidity increases significantly and then I run a de-humidifier. I turn it off in January, otherwise the air becomes too dry and there is a risk that the developing buds may shrivel.

If one of my very precious bulbs develops lesions, I use a very sharp and clean knife to cut out the bad bit quite deep into the bulb until there is just green flesh with no brown matter remaining. Then I dust the hole with sulphur or cinnamon powder. That stops any further rot. The bulb will look rather unsightly as a result, but it will still flower and produce healthy offspring.

Some pleiones eg. P yunnanensis always have brown spots, especially when they have been grown in peat mixtures. Peat seems to have that effect on other varieties, too, that's why I have stopped using it.

[mickeymuc]

Hi Maren,

Thank you for your information. I used something similar on the bulbs I suspected to have spots, so we'll see what happens. In spring an d summer I'll possibly use it again and hopefully have uninfected bulbs by then. Possibly one of my boxes got too wet in autumn when the weather was cool, so this might have contributed.
I'll keep you updaten on what happens to these pseudobulbs, I still have hope they can get over the infection.
Its very good you control the conditions during winter, so what can you recommend for humidity and temperature?

I also have a fungicide containing azoxystrobin, which works systematic and very well against many diseases - does anyone have experience if this is good for protecting Pleiones?

[Maren]

I keep my overwintering temperature above 2 degrees Celsius and relative humidity below around 70.