# Snow mold?



## SlipperKing (Jul 21, 2012)

Here is something, a fungus, that has been plague my slippers for months now. It has a detrimental effect on the roots especially seedlings. Who out there has dealt with this pest and had success with it? 

Here is a freshly unpotted plant of esquirolei turned up-side-down. The arrow is pointing at the bark but the agraflor, charcoal and the roots can have be infested.






Here I've unpotted several plants into a bucket to show that it is extensive.





The next two pics show the effect of the fungus/mold on the roots. These are not dead yet but see how the root turns a light brown? Eventually, The moisture/ life is sucked out of the root and it's dead!






(mold on roots)


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## cnycharles (Jul 21, 2012)

snow mold is usually a problem on short turfgrass (golf courses), but I have heard about it attacking rotten or not so hot tree bark in orchid media. I would have to see which fungicide is used to treat snow mold on turf. sometimes you can buy bags of landscape mulch and you'll see the snow mold spreading around inside the bag or a pile of mulch. it has to be starting from the bark, and then spreading to everything else. where do you get your bark, and what condition would you say it's in when you get it, or how do you store it?

of course, as I read articles on the internet about turf snow mold, that disease and this one that is being called 'snow mold' because it looks white, could very well be two very different things

after a little research, get rid of the rotten bark, remove bad roots and spray the rest with peroxide; let sit and dry a bit, repot into something with new bark in the media. if the bark has gotten wet somewhere and then sat around for a while especially in a hot place, the bark has already started to decompose. treating with some sort of fungicide won't really address the problem because rotting bark will again start rotting, and then cause other problems quickly again. I suppose you could pour peroxide through your pots, but you would still have media with rotting bark inside, and maybe not completely cure the fungus/rot


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## SlipperFan (Jul 21, 2012)

I have seen this a lot in pots that haven't been repotted in a long time. We just clean off the old mix, spray or dip the roots in a fungicide like Daconil or Funginex and repot. Problem solved.


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## emydura (Jul 21, 2012)

SlipperFan said:


> I have seen this a lot in pots that haven't been repotted in a long time. We just clean off the old mix, spray or dip the roots in a fungicide like Daconil or Funginex and repot. Problem solved.



I do the same thing and it doesn't work for me. It just returns quickly even in the new mix. It drives me crazy. I find it really dries the mix out and the plants can struggle to get water. They are permanently dessicated.

My problem can look a lot worse than Rick's. The whole mix will be just covered in this white mould.


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## SlipperKing (Jul 21, 2012)

Great suggestions Charles. I have begum to repot Dot so I hope that will clear things up. Bingo David! Plants struggle to survive with water competition going on.
This is the Orchidata brand of bark. Which is reported to last a very long time but maybe it has come to the end of it's usefulness


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## jtrmd (Jul 22, 2012)

SlipperFan said:


> I have seen this a lot in pots that haven't been repotted in a long time. We just clean off the old mix, spray or dip the roots in a fungicide like Daconil or Funginex and repot. Problem solved.



I used to do the same,but use Green shield.I want to say I was seeing it more in the clear pots more than others,but that could be my fuzzy memory.I also haven't seen it in awhile since I occasionally treat the whole GH with a preventative spray of Green Shield every few months,and got back on top of repotting yearly.


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## jtrmd (Jul 22, 2012)

SlipperKing said:


> Great suggestions Charles. I have begum to repot Dot so I hope that will clear things up. Bingo David! Plants struggle to survive with water competition going on.
> This is the Orchidata brand of bark. Which is reported to last a very long time but maybe it has come to the end of it's usefulness



I always assumed that when they say ''it lasts for a long time'' was just a marketing gimmick.


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## Shiva (Jul 22, 2012)

Got no problem with snow mold.


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## SlipperKing (Jul 22, 2012)

*Jim,
You may recall this posting by Roth: see the last paragraph*
Some Orchiata related remarks
There has been a lot of questions about Orchiata here and there, so now I make a sum up, after all I am tech advisor

As to the background and to avoid any questions as to why I post here or my purpose, yes I am paid by Orchiata to offer advise, especially to large commercial nurseries, fine ideas to improve it. However I am not paid by pallet sold and the large nurseries make the major part of Orchiata trade in the world. It is currently the first bark used in Japan, and along with Sphagnum Moss, now from Pacific Wide as well, I woudl say that Pacific Wide supplies most of the nurseries in Japan, directly or indirectly..........
*(I had to remove some of the text to fix it in!)*

...........There are some remarks to do about using orchiata:

- All the 'pine bark' are not equal. As an example, using fresh Pinus maritimus bark will destroy the roots. Some famous nurseries in France lost thousands of plants because of 'too fresh bark', that's why some publications advised about composting bark, where some advised using fresh bark. They were from different tree species, and their behavior were different.

- Orchiata and fresh Pinus radiata bark (sold under the name Kiwi amongst others) are vastly different products. Orchiata has been aged, the structure has been made hydrophilic, the pores have been opened during the process, and lime is applied to raise the pH. Fresh pinus radiata is usually hydrophobic, so when it is dry and watered it does not take water immediately, where Orchiata does. It has a low pH as well ( and the competitor's grading is more primitive too to be honest). Fred Clarke use fresh pinus radiata successfully so far, I will comment on that later, because it has involvements in the feeding program as well.

- The tannins and terpenes in Pinus radiata are different from the ones of the Rexius, Sequoia, or European barks. They do not stunt the roots. The structure in general of Pinus radiata makes it very stable, because the bonds are different from others pinus species, as long as they are grown in specific environment. Too hot countries or too cold, and the bark either delaminates or collapses. That's why Chile at a point tried to supply orchid bark made from Pinus radiata, but the way it grows in Chile makes it unsuitable without any questions.

- It is impossible to give advise for 'bark' like that. Depending on the type, the species, the process, there are many different reactions to be expected. So I will limit to Orchiata in this post, though if anyone has specific questions about other types, feel free to ask.

Orchiata should not be soaked in water to remove the materials that falls down at the bottom. This was valid for other types of bark, to remove some unsuitable materials, rotted pieces, wood... However Orchiata has been made HYDROPHILIC, so a fair part will indeed fall at the bottom of a bin. This is normal

Some people soak Orchiata anyway. I do so for some very expensive plants, just to have a peaceful mind, however the dust in itself is washed away after some waterings and I did not notice any difference, so I prefer to use it out of the bag. If it has been soaked, a part of the lime will be removed, and you may need to reapply lime, usually at 3kg/cubic meter. The rough surface of Orchiata chips ensures that the lime sticks well to the bark

Because of the rough surface, when you repot, there will be more air spaces, as the chips will be blocked by each other. Smooth chips of other barks will indeed slip and settle, making a more dense packing.

In the first days I used to mix it the way I did with the european bark, pumice or perlite, or sphagnum. Sometimes coconut products. I did not find any benefit at all, because orchiata by itself retains more water than the bark I was used to, at least in the first months. Orchiata after some years will still retain the same quantity of water per liter, where others barks tended to be hydrophobic at first, then suitable for root growth, then become spongy and deadly after some months or years

Indeed, I found that the smaller grades of Orchiata, Precision and classic, replaced wonderfully well sphagnum in all of its use ( except mounting on slabs of course ). So when I need to make a mix more water retentive, I use something like Classic + Power. For oxyglossum dendrobiums from Papua, I use exclusively the Classic grade.

Some remarks about Sphagnum. Many people have very good results with New Zealand sphagnum, that would be another post. However I do not like it for my plants at all. I found out that in many cases we used sphagnum because the roots are thin, and the plant needs a lot of water, regardless of the pH requirement of the plants. Such examples are Jewel orchids, many are growing on limestone outcrops, and becomes really massive in Orchiata, some of the Oxyglossum dendrobium like decockii, vexillarius... do grow either on rocks or as epiphyte on dead branches, hence the pH of their environment at their roots is neutral to alkaline, never acid. In sphagnum, when the sphagnum becomes sour, and due to the acidity of the sphagnum, the plants are wiped out. cuthbertsonii is way easier to grow in orchiata small grade than sphagnum...

Orchiata has been buffered with lime. As a result, there is a good amount of calcium and magnesium carbonate. The difference with a non processed Pinus radiata bark is essential. Orchiata can be used with both acidifying fertilizer (ammonium/urea ones) and nitrate based fertilizers ( though nitrate based fertilizers have some limitations, except if the plants are supplied with organic nitrogen or urea/ammonium periodically).

Fresh pinus radiata can be used safely for paphs (if it is not limed and aged) and quite a few other orchids only with nitrate based fertilizers such as MSU, because an acidifying fertilizer on an already acid bark would be a disaster.

Fresh pinus radiata bark is very resilient, and very hydrophobic, so it will stay acid for a while, no matter the lime applied outside. That is the main purpose of 'aging' orchiata, to make it hydrophilic, porous, and therefore very 'receptive' to the lime and the nutrient. It avoids too acid release from the bark, because the core of the chips take the water from the first day, where an hydrophobic bark will take the water layer by layer, releasing acid until the bark becomes hydrophilic...

It is very clear too that it is extremely difficult to use only nitrate based fertilizers and get nice plants of many specie. As for myself, I never succeeded, and the Dutches did not as a whole either. You need some urea, ammonium, or organic nitrogen. It has been supposed too that colonization by bacterias, years and fungi of the potting mix could convert nitrate into amino acids in a way, which would explain why some people can grow plants with only a nitrate based fertilizer and nothing else.

As to how to pot in Orchiata, I would say that the best is to mix the various grades ( I never mix it with sphagnum, the results of an Orchiata + NZ sphagnum mix were inferior to pure orchiata when I, and the Japanese tried it) to get the suitable water retention and particle size. *Additions of perlite, etc... were unnecessary, perlite or pumice were used first to retain water, but orchiata does retain water already, then to improve the mix structure, but in this case the orchiata structure does not change, even after years of heavy feeding under hot conditions. Mukoyama orchids have plants potted nearly a decade ago in orchiata, as tests, and there are no structure problems.*
__________________


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## SlipperKing (Jul 22, 2012)

Several have mention that the mold is growing because the bark is rotten. That's not really the case. I would guess-o-mate 80% of the bark is still "rock hard"


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## likespaphs (Jul 22, 2012)

jtrmd said:


> I used to do the same,but use Green shield....



really? no detriment to the plant?


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## Rick (Jul 22, 2012)

I like baskets with no bark.

From what I've been seeing with basket culture, and a few small comparison tests of plants in pots, (but in the same substrate composition as the baskets), that aeration levels are the big driver in rhyzosphere and ultimately root health in potted orchids.

The aircone pots compared to baskets still didn't cut it. Drilling a bunch of extra holes in an aircone pot helped a bit more. Drilled out Aircone pot with very open media (lots of inerts too) with low K seems to work pretty good too.

Funny that the notion of turf grass came up in conjunction with this fungus. I was researching (for a water quality/toxicity project) the makeup of factory residuals from a fertilizer plant. Ended up looking at a Scott's brand fert catalog. There most toted new turf grass product has 20-1-1 NPK. I think there was a cal mag component too.

From some acquaintances who manage golf courses, the old school approach was application of "balanced" fertilizers with copious additions of various fungicides. Sometimes, for hot dry summers, increased application of very high K fert was applied to get deeper roots for dry winter survival. 
I believe the fungicides were usually copper based.

Ultimately their was significant outcry from locals who didn't like their streams and creeks constantly being trashed, with lots of finger pointing at golf course runoff. So looks like there may be a shift in management philosophy on the turf grass management side of life too.


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## emydura (Jul 22, 2012)

SlipperKing said:


> Several have mention that the mold is growing because the bark is rotten. That's not really the case. I would guess-o-mate 80% of the bark is still "rock hard"



That is my experience as well. I have repotted the affected plants into a new mix which was quickly overrun with this mould. 



Rick said:


> I like baskets with no bark.
> 
> From what I've been seeing with basket culture, and a few small comparison tests of plants in pots, (but in the same substrate composition as the baskets), that aeration levels are the big driver in rhyzosphere and ultimately root health in potted orchids.



I used one of those pots that had slits right down the sides and the mould still became established.


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## jtrmd (Jul 22, 2012)

likespaphs said:


> really? no detriment to the plant?



One time I didnt pay attention and switch the rate on the hose end sprayer,and got some minor leaf bleaching.Other than that I havent noticed anything.

I did have that rot issue pop up on me out of nowhere last winter I think, when I just wasn't feeling the Orchids,and said screw all the unnecessary work.I cant blame it all on not spraying the GH down at all that winter,or just the laziness in all around culture.


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## jtrmd (Jul 22, 2012)

Thanks for the info.





SlipperKing said:


> *Jim,
> You may recall this posting by Roth: see the last paragraph*
> Some Orchiata related remarks
> There has been a lot of questions about Orchiata here and there, so now I make a sum up, after all I am tech advisor
> ...


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## Rick (Jul 22, 2012)

emydura said:


> I used one of those pots that had slits right down the sides and the mould still became established.



Did you stick with bark or chc or switch to moss/gravel?


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## Stone (Jul 22, 2012)

You may want to consider a couple of things. These type of molds usually proliferate in acid rather than alkaline media, in dry rather than wet media and often in imature media. ie: that the bark (not sufficiently composted) has a low population of decomosing bacteria which out-compete fungi or use them as food. So, drenching the pots in hydrated lime solution with a little fish emulsion MAY help to restore the balance. I have seen it from time to time and always in pots that have been left too dry for a time. If your bark had become water repelent (hydrophobic) no amount of watering will help without dipping in a wetting agent.
Hope you get on top of this!


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## Rick (Jul 22, 2012)

Stone said:


> often in imature media. ie: that the bark (not sufficiently composted) has a low population of decomosing bacteria which out-compete fungi or use them as food.



Yes it seems like fungi are the first wave of what softens up a downed tree in the woods around here.


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## NYEric (Jul 22, 2012)

It's a problem with bark! If its a heavy duty problem use another media!


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## emydura (Jul 22, 2012)

Rick said:


> Did you stick with bark or chc or switch to moss/gravel?



I've seen it in both bark and CHC. It seems to be much less of a problem for me than in the past when it was a bit chronic. I have the odd plant with it now. Since going back to Debco bark the problem has greatly declined.



Stone said:


> You may want to consider a couple of things. These type of molds usually proliferate in acid rather than alkaline media, in dry rather than wet media and often in imature media. ie: that the bark (not sufficiently composted) has a low population of decomosing bacteria which out-compete fungi or use them as food. So, drenching the pots in hydrated lime solution with a little fish emulsion MAY help to restore the balance. I have seen it from time to time and always in pots that have been left too dry for a time. If your bark had become water repelent (hydrophobic) no amount of watering will help without dipping in a wetting agent.
> Hope you get on top of this!



What you say Mick is my experience as well.


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## Roth (Jul 23, 2012)

Stone said:


> You may want to consider a couple of things. These type of molds usually proliferate in acid rather than alkaline media, in dry rather than wet media and often in imature media. ie: that the bark (not sufficiently composted) has a low population of decomosing bacteria which out-compete fungi or use them as food. So, drenching the pots in hydrated lime solution with a little fish emulsion MAY help to restore the balance. I have seen it from time to time and always in pots that have been left too dry for a time. If your bark had become water repelent (hydrophobic) no amount of watering will help without dipping in a wetting agent.
> Hope you get on top of this!



Those photos sound very familiar. The Dutches used to coin the term 'Water vapor fungus' back to the 90's. It is not related to Orchiata or the bark by itself, but it is a contamination ( like a fusarium would contaminate a plant, this fungus contaminates the potting mix, bark or tree fern, etc...).

It has been correlated usually to a low EC of the potting mix ( not the fertilizer, but the potting mix). In the Netherlands, they usually increase the EC and do not use any 'periodic flushing', which suppress the problem.

As a fungicide, you can try only few that may work. It is not a pathogenic fungus, nor a 'common' fungus, hence many fungides are ineffective. I know as a fact that Dithane drenches can kill it. Physan, Zerotol, etc... will have no effects. Captan works well but can stop the root growth. This kind of fungus can indeed attack the roots.

That's actually something pretty stupid we can read here and there. The 'fungus gnats', some fungus, some insects, some mites, 'live on decaying matters'. This is plain stupid to say that. In fact, anything that can eat 'decaying organic matter' can care of orchid roots nicely, given the starvation, the conditions...


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## Stone (Jul 23, 2012)

Roth said:


> > It has been correlated usually to a low EC of the potting mix ( not the fertilizer, but the potting mix). In the Netherlands, they usually increase the EC and do not use any 'periodic flushing', which suppress the problem.
> 
> 
> 
> Does orchiata treat their bark with Iron sulphate and super phosphate etc? Many fungi do not like P


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## Roth (Jul 23, 2012)

Stone said:


> Roth said:
> 
> 
> > Does orchiata treat their bark with Iron sulphate and super phosphate etc? Many fungi do not like P
> ...


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## NYEric (Jul 24, 2012)

Interesting info.


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