Slow growing rust discolouration around base of Paph. kolopakingii

[Kate Boyce-Miles]

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.

 

[troy]

What is your afternoon grow area temp?

 

[Kate Boyce-Miles]

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.

 

[Kate Boyce-Miles]

Does anyone have any idea of what this might be?

 

[Guldal]

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!

 

[Kate Boyce-Miles]

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).

 

[Guldal]

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!

 

[DrLeslieEe]

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.

 

[Kate Boyce-Miles]

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.

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?

 

[Kate Boyce-Miles]

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.

 

[SuperPaph]

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.

 

[Kate Boyce-Miles]

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?

 

[spujr]

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.

 

[Kate Boyce-Miles]

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?

 

[spujr]

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:

 

[Kate Boyce-Miles]

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).

 

[spujr]

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.

 

[Stefan Neher]

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.

 

[southernbelle]

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.

 

[Kate Boyce-Miles]

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.