Brown Rot?

[Harlz]

Hi all, interested in your thoughts and suggestions on three of my Paphs which are showing signs of Brown Rot, I think?

This past summer we had a very wet January followed by a very warm, dry Feb/Mar with well above average temperatures. During this time my plants are all outside under shade cloth only. They are a bit crowded which probably explains how it has spread.

Are these plants salvageable? Options for chemical control are a little different here in Australia compared to overseas. E.g. don't think I've ever seen Physan sold here.

The Paph. Bellatulum (middle pic) I'd hate to have to give it is last rites. Seedlings of this species are especially uncommon here and expensive. I've had this plant for only two years, the first year a slug chewed off most of it but like a trooper it grew back only to succumb to this the following year.

 

[Linus_Cello]

The first one I don't think is salvagable, but I think the other 2 are salvagable. Repot them all. The first one looks too wet.

 

[SlipperFan]

If the rot is in the crown, I don't know how you can save it.

If the spots on the leaves aren't spreading, I would just treat them, but if they are spreading, I'd cut the leaves off just a bit past the spots and treat the cut with cinnamon.

Good luck!

 

[troy]

I agree #1 is a gonner, cut the bad spots off #2-3 and repot then peroxide or douse in peroxide then repot

 

[NYEric]

Number 1 is in bad shape. If you had some Dragon's blood, maybe. The other 2 should be fine. The spots look like those you get on roses from water splashing off the ground.

 

[Ozpaph]

looks bacterial.???
I'd use some physan as a drench then liberally dust both sites of the affected leaf (and crown) with cinnamon. Repeat in a few days.
Keep drier. Good air movement and quarantine.
Spray/drench everything else with mancozeb or kocide(not dendrodes with the later).

 

[Harlz]

Thanks very much for the replies and advice, much appreciated. I've already started working on sorting this out.

 

[phraggy]

Number 1 is in bad shape. If you had some Dragon's blood, maybe. The other 2 should be fine. The spots look like those you get on roses from water splashing off the ground.

Eric. You can get Dragons Blood from the UK ebay site for under a tenner.

Ed

 

[Justin]

It is a fungal infection. First plant is gone...pitch it.
Agree cut off parts from the other plants with a sterile tool then look at culture to prevent in the future. Good luck.

 

[emydura]

The first one looks in trouble. Is that a new growth I can see? If so, that might be OK. The potting mix needs to be replaced though. It looks a little broken down, especially for a Brachy. The other two should not be a problem as long as you stop the rot.

While you can't get Physan in Australia you can use a pool algaecide which is the exact same chemical (Benzyalkonium Chloride). It is a lot cheaper too and a little safer to use as it is not as highly concentrated. This one from Bunnings will do the trick. You can get a 2 litre version.

http://www.bunnings.com.au/hy-clor-5l-pool-algaecide_p3090185

For concentrations for rots such as black rot, brown rot, Erwinia etc
15 mls to 4 litres of water (3.75ml per litre) . Remove compost, soak entire plant 10 minutes or more. Trim all rot from plant using sterilized cutter. Soak plant wounds 10 minutes or more. Repot using compost soaked with Algaecide solution.

 

[Ozpaph]

David, have you tried that?
You can import Physan from the US via eBay - but pool stuff does look easier and cheaper.

 

[Ozpaph]

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7420.html

 

[emydura]

David, have you tried that?
You can import Physan from the US via eBay - but pool stuff does look easier and cheaper.

Yes, I have been using it for a few months. I think it is pretty effective. I also spray it regularly at a lower concentration as a preventative measure. It is the same ingredient as Physan and it is so cheap. So I don't think there is much point in importing Physan. There is more information in our Bulletin starting on page 7 -

http://www.canberraorchids.org/Pubs/BulletinMay14.pdf

I came across this when looking for a solution to the problem of snow mould. Some of my Paphs get that white fungus through the potting mix which I had found impossible to get rid of. None of the conventional fungicides worked. But I read that a fungicide containing Benzylalkonium Chloride would eradicate it. However none of the fungicides in Australia contained this ingredient. I worked out Physan did but it is no longer available here anymore. Then I worked out these pool algaecides are the same as Physan. I have soaked a few plants with snow mould and so far so good. But it takes a while before you are confident it is fully gone.

 

[NYEric]

Eric. You can get Dragons Blood from the UK ebay site for under a tenner.

Ed

Ed, that's probably processed. It is not the same as pure. Read the DB thread.

 

[Ozpaph]

very helpful - thanks David.

 

[Happypaphy7]

I would have pitched the first two, although the second one might be salvageable after much time because of the affected area that are damaged (this should be removed).

The second one still has rather "fresh" disease marks. See how wet it looks?
You don't want the juice out of those marks as it is full of stuff. lol
I would cut those leaves off.

The last one could easily be saved.

Good luck!

 

[NYEric]

I am saving 2 plants in the same or worse condition than the first with Dragon's blood, I will take photos for when I can finally post.

 

[Happypaphy7]

The first one has center rotten.
Worse than that would be a dead plant? oke:

 

[emydura]

The first one has center rotten.
Worse than that would be a dead plant? oke:

A plant with rot in the centre is still capable of putting out healthy new leads. I have a roth that got rot in the centre and it subsequently put out two new leads. 18 months later those two growths are now about 30-40 cm wide. It is the fastest growing roth in my collection.

 

[Happypaphy7]

Great! It's tough save.
I guess if somehow crown rot stops and does not progress deep in the center, it's possible.

How did you arrest the rot?