Paphiopedilum rot

[meridiannight]

Today I discovered a rot on my only Paphiopedilum.

It had been very slowly developing, with next to no outward signs of trouble. There was one brown spot on a leaf, but it had been small until now, and didn't look problematic (came like that from the nursery). Only in retrospect do I see its significance. (The spot looked like Erwinia).

Anyway, the leaves all look completely healthy except for that single one with a spot that I removed. It was crown rot at the base, deep down in the potting media. Rotting media was surrounding the base of the plant and the roots down there. It didn't become visible until I took the plant out of the pot. I removed most of the roots, saved a few. Sprayed it with hydrogen peroxide. Cut the flower spike and potted it into a new pot. No idea if it's going to survive...

Oh, and some little black bugs (winged) had been living in the potting media as well.

This Paph has been with me for a month, and I really like it. Any suggestions on how to treat it now, to increase its chances of survival?

[aliceinwl]

Hydrogen peroxide sprayed on roots can be lethal because it damages the tissue. Don’t apply any more to the roots.

Are the roots still alive? Are there any unaffected fans? I ended up having something similar happen to a Paph I waited too long to repot. In my case the roots looked okay as well as one established fan and one new fan. I divided mine and was able to keep the bulk of the root mass with the one established healthy fan. The one healthy new fan, however, separated without any roots.

I decided the systemic fungicides were more toxic than I wanted to deal with. I potted up the healthy and diseased fans separately and put the healthy rootless fan in an ICU set-up (overnight soak in Kelpmax, then potted into moist spagnum, with the pot placed in a clear container with a ventilated bag over the top to reduce water loss).

Over the next month all of the fans that showed any signs of rot succumbed: rotted out at the base. The one healthy fan appears to be okay and the rootless healthy fan is also growing. I’m definitely going to be more proactive about repotting my Paphs.

[meridiannight]

The roots are still alive. I looked up how to deal with this thing, and it was recommended to use hydrogen peroxide in cases of rot, if one didn't have or didn't want to use a fungicide. I have no fungicides.

I have only 2 fans, and I think both were affected. I didn't separate them. I potted them both up in the new pot. Crossing my fingers they survive.

[aliceinwl]

Hydrogen peroxide is just going to kill vulnerable surface tissues: your plants roots and any exposed fungal tissues. Fungi growing within the roots will be fine and root function can be severely damaged due to injury of surface tissues. You might be okay with a surgical application to a mushy spot, but roots shouldn’t be sprayed prophylactically. This seems to be a very popular treatment on the internet :-(

If you have access to a kelp based rooting stimulant that may be worth a try to boost health and promote new root growth. A picture would help. Cutting leaves is risky but is sometimes an option if the rot can be removed safely that way.

[meridiannight]

Originally Posted by aliceinwl

Hydrogen peroxide is just going to kill vulnerable surface tissues: your plants roots and any exposed fungal tissues. Fungi growing within the roots will be fine and root function can be severely damaged due to injury of surface tissues. You might be okay with a surgical application to a mushy spot, but roots shouldn’t be sprayed prophylactically. This seems to be a very popular treatment on the internet :-(

This is misinformation. Hydrogen peroxide 3% is perfectly safe to spray on the roots. Many growers do this, with no adverse effects. Some research even suggests benefits to roots.

My Paph is fine, roots are fine, it's producing new top growth. And I sprayed it with hydrogen peroxide not once but twice.

Also, fungus does not live inside the root tissue. It comes from the outside, it is an external pathogen. And the only way it gets inside is from the outside. In which case there is clear external damage visible when looked.

So, I am not following your advice.

[Swimmingorchids]

meridian, you are free to do whatever you want but take it from someone who loves hydrogen peroxide and has been experimenting with it for years.

3% is too strong. Simple as that. Did it kill your plants? Nope very likely not so don't worry too much but it will most likely have stunted growth for a week.

Like I said you can do what you want and your orchids will survive but let me tell you that if you spray 3% hydrogen peroxide on a tomato plant the leaves will turn brown and die. Now you might say ok orchids are not tomatoes. Ok fine, spray a dandelion with 3% hydrogen peroxide, see what happens.

Most plants will suffer from 3% hydrogen peroxide.

Now I did say that I love hydrogen peroxide - it's great stuff and does a brilliant job at 0.3%. Use at 0.3% and it will kill all funguses and not do any damage to your roots. Double bonus but like said do whatever the internet has told you to do - I love the internet too.

[SouthPark]

Originally Posted by aliceinwl

but roots shouldn’t be sprayed prophylactically. This seems to be a very popular treatment on the internet

alice ------ I once sprayed all of my incoming mail order (catts) with H2O2 ..... leaves, roots and all. Lots of these orchids. It was 3% and 5% concentration.

I never had any fatalities. However...... and this is the big however ...... I do sense that these H2O2 root-treated plants all took a relatively long time to begin 'growing'. I do have some sort of feeling that the H2O2 made the plants take a while to get 'growing'. I'm thinking it's possible that the H2O2 will not just take out some fungus ----- but possibly also take out some beneficial organisms and even stunt root growth for a while.

So now, whenever I pot/repot most of my incoming plants (from the mail), I do not use H2O2 anymore. At least not on the roots. Instead, I just spray some mancozeb on the plant and the roots just prior to repotting.

Perhaps the concentration that swimmingorchids is using might be the key. I still keep fresh bottles (unopened) of 3% and 5% H2O2, but haven't used H202 for quite a while. Conditions over here are quite good - I haven't got issues with fungus.

But as for 0.3 percent concentration being effective on fungus. I definitely don't know. I'm just going to stick with manozeb, as that's what I've switched to. Reason is because once you open a bottle of H2O2, it begins to degrade.