# Slow growing rust discolouration around base of Paph. kolopakingii



## Kate Boyce-Miles (Jun 4, 2020)

Hello. My flowering size P. kolopakingii has what I describe as 'rust' slowing developing around its base. It has had this for a long time now, but is getting worse. I have been spraying it with 3% hydrogen peroxide, as well as Rose Clear Ultra (fungicide). In the last few weeks I have also greatly increased the air movement in my grow house, and have applied treatments for spider-mite (incase it might be that). 

I am worried because this 'rust' is spoiling the look of my plant, and I really want to get rid of it. A few other of my Paphs also have this, and I am not sure what is causing it. I do notice that it gets worse in particularly warm weather though.


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## troy (Jun 4, 2020)

What is your afternoon grow area temp?


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## Kate Boyce-Miles (Jun 4, 2020)

troy said:


> What is your afternoon grow area temp?


About 18-20 degrees C, on sunny days it goes to mid to high twenties. I keep to minimum 15C at night.


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## Kate Boyce-Miles (Jun 5, 2020)

Does anyone have any idea of what this might be?


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## Guldal (Jun 5, 2020)

I would remove that lowest leaf with the clearest dark spot, whether the browning is due to necrosis or rot! 

Your thought of it being a possible (false spider) mite infection sounds to me not to be totally of the track. Have you studied the plant with a good botanical magnifying glass (sometimes this is, what is needed to see, what you actually do not want to see!)? If a mite infection, they might really thrive, if you keep your plants a wee bit on the (too) dry side?

Sometimes if I myself cannot determine, what's cooking, I hurry up and bring my plant to my friend/mentor in all things orchiadic, mr. Hans Christiansen in Fredensborg to benefit from his vast knowledge and long term experience (50+ years as independent nursery owner). If you have in your vicinity a nice orchid nursery with which you some times deal, if they are decent people there, they would probably offer you some good advice!


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## Kate Boyce-Miles (Jun 5, 2020)

Guldal said:


> I would remove that lowest leaf with the clearest dark spot, whether the browning is due to necrosis or rot!
> 
> Your thought of it being a possible (false spider) mite infection sounds to me not to be totally of the track. Have you studied the plant with a good botanical magnifying glass (sometimes this is, what is needed to see, what you actually do not want to see!)? If a mite infection, they might really thrive, if you keep your plants a wee bit on the (too) dry side?
> 
> Sometimes if I myself cannot determine, what's cooking, I hurry up and bring my plant to my friend/mentor in all things orchiadic, mr. Hans Christiansen in Fredensborg to benefit from his vast knowledge and long term experience (50+ years as independent nursery owner). If you have in your vicinity a nice orchid nursery with which you some times deal, if they are decent people there, they would probably offer you some good advice!



Thank you for your response. I have removed that lower leaf. I do keep my slippers on the dry side because I am very anxious about causing root rot. I have them all in a very free draining mix of medium grade orchiata, pumice and charcoal. Unfortunately I do not have a decent magnifying glass (I need to get one), but I will spray again with spider mite control incase it is that (the product I use recommends multiple applications anyway).


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## Guldal (Jun 5, 2020)

If it is (false - if no web present) spider mites, find some litterature/web-page and read about their hatching cyklus and how to apply the several times applied insect control in relation to that...or look around in this section of STC, where you might find usefull information, or contact some of the contributors, that have multifold knowledge and experience compared to me, and send them a pm through the 'Conversations'-feature letter-sign in the upper right corner. I'm sure most people will be happy to help a fellow, human orchid grower!


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## DrLeslieEe (Jun 5, 2020)

You could do two things:

1. spray the entire plant with horticultural oil (treat other plants that were around it as well). This is a contact insecticide to kill mites. 

2. when dry, sprinkle cinnamon or sulphur on all browned areas and keep in high ventilation area to dry off for 2-3 weeks. 

Then repeat in 7-10 days. 

That’s what I would do. 

Sometimes repotting to check roots is always a good thing.


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## Kate Boyce-Miles (Jun 5, 2020)

DrLeslieEe said:


> You could do two things:
> 
> 1. spray the entire plant with horticultural oil (treat other plants that were around it as well). This is a contact insecticide to kill mites.
> 
> ...



Thank you for your advice, Dr Leslie. I will definitely spray it and my other Paphs that are on the same table and apply sulphur. 
I could have a look at the roots, I only repotted it three months ago though and am worried that it might add to the plant's stress, or do you think it is best to check anyway?


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## Kate Boyce-Miles (Jun 5, 2020)

Guldal said:


> If it is (false - if no web present) spider mites, find some litterature/web-page and read about their hatching cyklus and how to apply the several times applied insect control in relation to that...or look around in this section of STC, where you might find usefull information, or contact some of the contributors, that have multifold knowledge and experience compared to me, and send them a pm through the 'Conversations'-feature letter-sign in the upper right corner. I'm sure most people will be happy to help a fellow, human orchid grower!


Thank you very much for your kind advice, Guldal.


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## SuperPaph (Jun 7, 2020)

Although climes are not similar, I think the way on which fungus develope are similar at all aroud the world. In my experience, and watching the kind of lessions this plant is showing, it looks to be a fungus, a dry fungus, that first kills the stome, and begin to "run" along a "line of cells". I suggest to apply Phytont and one week later Mancoceb. Although the plant has not too much pretty leaves due the spots, I would never cut those leaves, because more than the 95 % of it surface is in perfect conditions, and are fulfilling their funtions. About the perfection.... it is not of this world.


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## Kate Boyce-Miles (Jun 7, 2020)

SuperPaph said:


> Although climes are not similar, I think the way on which fungus develope are similar at all aroud the world. In my experience, and watching the kind of lessions this plant is showing, it looks to be a fungus, a dry fungus, that first kills the stome, and begin to "run" along a "line of cells". I suggest to apply Phytont and one week later Mancoceb. Although the plant has not too much pretty leaves due the spots, I would never cut those leaves, because more than the 95 % of it surface is in perfect conditions, and are fulfilling their funtions. About the perfection.... it is not of this world.



Thank you for your response. I have applied yellow sulphur powder to the affected areas. Unfortunately I cannot acquire those chemicals in the UK. I do have a product containing myclobutanil though, would this be safe to use on Paphs?


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## spujr (Jun 7, 2020)

Hi, I noticed something similar on my Bel Royal (Roth x kolo). I noticed it after bringing the plant inside the house but it could of occurred earlier. In my case, I think it is a physiological response to temperatures and not biotic stress. It doesn't seem to spread or cause leaf death so while I am keeping an eye on it right now I'm not too concerned.


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## Kate Boyce-Miles (Jun 7, 2020)

spujr said:


> Hi, I noticed something similar on my Bel Royal (Roth x kolo). I noticed it after bringing the plant inside the house but it could of occurred earlier. In my case, I think it is a physiological response to temperatures and not biotic stress. It doesn't seem to spread or cause leaf death so while I am keeping an eye on it right now I'm not too concerned. View attachment 20574


Nice Bel Royal! I have a newly acquired near-flowering size one. How do you find it to grow?


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## spujr (Jun 7, 2020)

Kate Boyce-Miles said:


> Nice Bel Royal! I have a newly acquired near-flowering size one. How do you find it to grow?


Thanks! I posted some flowers recently on another thread and just repotted it. I find it to be one of the easier and most vigorous growers in my collection. My main problem is how big it is . It was tolerant to the abuses of moving and extreme temperatures. I have it in pure sphagnum moss and under the brightest lights. The moss is usually wet, and doesn't go completely dry between waterings. Attached are some photos of being repotted. 

Taken out of pot:



After removing the old moss and dead roots. 



Finished:


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## Kate Boyce-Miles (Jun 7, 2020)

How often do you water and what do you feed, out of interest?  May I have the link to the thread with the flowers? (I must have missed it).


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## spujr (Jun 7, 2020)

Kate Boyce-Miles said:


> How often do you water and what do you feed, out of interest?  May I have the link to the thread with the flowers? (I must have missed it).


https://www.slippertalk.com/threads/paph-bel-royal-kolopakingii-x-rothschildianum.49371/

I use a ~25ppm CalMag 12-1-1 feeding on every watering. I water every other day, sometimes daily. Temps are between 20-28C.


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## Stefan Neher (Jun 10, 2020)

spujr said:


> Hi, I noticed something similar on my Bel Royal (Roth x kolo). I noticed it after bringing the plant inside the house but it could of occurred earlier. In my case, I think it is a physiological response to temperatures and not biotic stress. It doesn't seem to spread or cause leaf death so while I am keeping an eye on it right now I'm not too concerned. View attachment 20574



I have also this problem on just ONE of my 3 Phrags, and I thought it might be due to some weird manifestation of sunburn or heat stress, as you said, but only one plant is affected. 

What leads you to believe it is due to temperatures or something otherwise physiological? I want to agree with you, because I'd hate to think I had a virused/fungused plant. 

My plants are in an East window, and thus, get some direct sun for a few hours in the morning right now, as we approach the solstice, and even more direct sun in the winter, when it's at a lower angle, but this is the first time the issue has manifested on this or any of my plants.


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## southernbelle (Jun 11, 2020)

Kate Boyce-Miles said:


> Thank you for your response. I have removed that lower leaf. I do keep my slippers on the dry side because I am very anxious about causing root rot. I have them all in a very free draining mix of medium grade orchiata, pumice and charcoal. Unfortunately I do not have a decent magnifying glass (I need to get one), but I will spray again with spider mite control incase it is that (the product I use recommends multiple applications anyway).


Get a powerful one! Some tiny things in the false mite family take 60 power for me to see. I’m used to roses where you can see anything on them with 10 power. Not so in my experience with my orchids.


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## Kate Boyce-Miles (Jun 11, 2020)

southernbelle said:


> Get a powerful one! Some tiny things in the false mite family take 60 power for me to see. I’m used to roses where you can see anything on them with 10 power. Not so in my experience with my orchids.


I have sprayed all my Paphs with spider mite control a few days ago. I will do so again just to make sure.


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## southernbelle (Jun 12, 2020)

Kate Boyce-Miles said:


> I have sprayed all my Paphs with spider mite control a few days ago. I will do so again just to make sure.


I think it’s 3 sprays 5-7 days apart but check on it.


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## Kate Boyce-Miles (Jun 19, 2020)

This turned out not to be spider mite. It is some foul fungal pathogen which allowed entry of secondary bacterial infection which finished it off. The kolopakingii has completely succumbed to it despite being under the fan constantly and treated with powerful doses of hydrogen peroxide. I tried sulphur and cinnamon but it did nothing for it. A few more of my plants are also affected now and I am very upset about this. The second image is a stonei x praestans which is affected. Please does anyone have an idea of exactly what the fungus is? The only thing I can think of is southern blight/collar rot.


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## musa (Jun 20, 2020)

No idea what it could be. Years ago I lost a kolo the same way. The stonei x praestans seems to get a new shot if it is quick enough it could make it, my lowii survived that way but it will take time...


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## GuRu (Jun 20, 2020)

Kate, unfortunately I read this thread not before today and in my eyes it's clearly a beginning fungus infestation. I thing SuperPaph was on the right track even a fortnight ago.


SuperPaph said:


> Although climes are not similar, I think the way on which fungus develope are similar at all aroud the world. In my experience, and watching the kind of lessions this plant is showing, it looks to be a fungus, a dry fungus, that first kills the stome, and begin to "run" along a "line of cells".



I'm no expert, I only repeat what I read and I just can point on this site about Orchid diseases of the HARK Company, a German orchids propagating laboratory.
One kind of fungus which I would think can cause your problems is COLLETOTRICHUM the other on one is RHIZOCTONIA. Unfortunately you can't not anymore switch the language to English on the HARK site but you can see few photos and the names of the fungi and with that you can start a search in English.
One certain sign of a fungus infestation is......you can smell it if you go with your nose closely to the infested site.
The most important thing is reduce humidity, reduce watering and stop spraying.
I used to use a paste of cinnamon powder steered with some drops of water and one drop of washing-up liquid. This paste I apply with a small paint brush.
Good luck and all the best to your plant.


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## Kate Boyce-Miles (Jun 20, 2020)

GuRu said:


> Kate, unfortunately I read this thread not before today and in my eyes it's clearly a beginning fungus infestation. I thing SuperPaph was on the right track even a fortnight ago.
> 
> 
> I'm no expert, I only repeat what I read and I just can point on this site about Orchid diseases of the HARK Company, a German orchids propagating laboratory.
> ...



Thank you for your response. Do you know what chemicals are affective against these two you have mentioned?


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## GuRu (Jun 20, 2020)

Kate, I always used with reasonable success my cinnamon paste and since I've stopped spraying when watering the infestations decreased remarkable. On the HARK site they recommend some fungicides, for example (Mancozeb, Metiram, Maneb) but I think on the one hand these are for professional use only and on the other hand they might be named different in UK. I'm not sure but I think you live in UK.


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## Kate Boyce-Miles (Jun 20, 2020)

GuRu said:


> Kate, I always used with reasonable success my cinnamon paste and since I've stopped spraying when watering the infestations decreased remarkable. On the HARK site they recommend some fungicides, for example (Mancozeb, Metiram, Maneb) but I think on the one hand these are for professional use only and on the other hand they might be named different in UK. I'm not sure but I think you live in UK.


Thank you for the reply. Cinnamon does work perhaps on some of my orchids, just this particular fungus seems really virulent and cinnamon does nothing to control it. I do live in the UK, yes, and it is very frustrating to me that these chemicals exist that could potentially treat this disease yet I cannot get hold of them.


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## GuRu (Jun 20, 2020)

Kate, maybe you can start an internet search and find out the trade names of these fungicides/substances in UK or maybe there is a nursery nearby the place you live which can help you out with a reasonable fungicide?


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## eds (Jun 20, 2020)

If they are available in the EU then we should still be able to order them (for now!) into the UK. You might have to buy them from Germany though!

The range of fungicides is rather lamentable I'm afraid to us domestic growers over here.


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## Ozpaph (Jun 21, 2020)

Those last 2 pictures look like bacterial rot. Lower humidity. More airflow. Try cinnamon. If it gets bigger i would remove those leaves.


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## Kate Boyce-Miles (Jun 21, 2020)

Ozpaph said:


> Those last 2 pictures look like bacterial rot. Lower humidity. More airflow. Try cinnamon. If it gets bigger i would remove those leaves.


Yes bacterial rot moved in, but a fungal disease started first. I have done all that and cinnamon actually made it worse. One of these plants is now dead.


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## werner.freitag (Jun 22, 2020)

yes, looks like bacterial rot


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## Ozpaph (Jun 22, 2020)

You have to 'cut it out' very early to win. Maybe try Dragons Blood topically and the cinnamon. Ive not tried H2O2 but some use it.


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## Justin (Jun 22, 2020)

Bacterial rot. I would remove that leaf and treat the plant quickly with Phyton 27.

Roberts has it: Home INDEX


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## Russ1992 (Nov 22, 2022)

All of these pictures from different users show Rhizoctonia to me except @Kate Boyce-Miles last two images that do appear to be bacterial. If you go to the Hark Orchideen website the rusted neck looks EXACTLY like Rhizoctonia. This comes from poor air circulation at the roots and being too moist for too long. The above in combo with high humidity and high temps with poor air movement almost ensures problems to take hold. It’s important to note however that the host plant can also infect nearby plants that are strong with good culture. This is a soil born disease which is why it is visible first at the base of leaves, but at that point it has probably already infected the roots. The infection noticeably slows down or stops growth. Lower leaves yellow with brown smears and spots dotting them at the base. In most cases this progresses slowly but in seedlings I have seen them deteriorate rapidly. I have been struggling with these same issues.

I have been told to apply Hydrogen peroxide, and Physan by nursery growers but these treatments seem pretty ineffective.

AOS states that the following can be used:

Thiomyl
Banrot
Clearys 3336
Terraclor
Zyban

Some ST users advocate using

Zerotol
Liquid Copper

In my experience Thiomyl is ineffective when a plant is already infected. Zerotol seems to slow the advance of the infection but doesn’t eradicate it.

Interestingly one user advises that there is just one fungicide that will work for a current Rhizoctonia infection: Rizolex. The active ingredient is Tolclofos-methyl.

I haven’t tried this Rizolex or many of the others but will probably give it a go. Will report back my findings.


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