Psychopsis Kalihi

[yann....@gmail.com]

Hello Dennis,

I bought a Psychopsis Kalihi at the Pacific Orchid Exposition 3 or 4 years ago.

She now has 9 spikes with flowers and is growing 2 new spikes. She's behind a window facing East and she's getting "fresh" air pretty much every day for at least 2-3 hours.

I think she's doing good. However, she has black stains on some leaves as well as on some spikes. 2 other leaves have large grey/brown spots. 

I used diluted Physan 20 about 3 weeks ago and I did not see any "improvements". I understand it may take time but I am wondering if I should use something different to treat my Psychopsis.

Could you please have a look at the photos I posted here: https://drive.google.com/folderview?id=0B7-K7jtItI_7TWJSTWU5dS0xdkk ?

It would be greatly appreciated if you could help me figuring out what is going on.

Best regards,

Yann

[dennis westler]

Dear Yann:

Damaged leaves will unfortunately never recover cosmetically, as plants lack the ability to heal as we do. So marks like this will remain. These things both look to me to be environmental damage rather than a disease or infestation. I need to know it these areas appeared at their full extent (slowly appearing over the whole area over 3-10 days), or if they grew slowly from smaller spots, perhaps of a different color. My feeling it that they are both the results of temperature and humidity conditions, essentially scorching of the leaves which would happen quickly but take days to become visible.  In this case the use of physan was a good idea to prevent secondary infection. If the leaves with gray areas are also kind of bumpy in those areas it is a tissue collapse that occurs under certain conditions (when the roots are pushing more moisture into the leaves than they can transpire causing cells to burst). This would also happen all at once, but take days to become visible. Fungus would generally begin as small well defined areas with (usually) yellow margins. It would never appear at once over a large area of the leaf.  

While fresh air is important, air movement is more so, especially to prevent too much heat from accumulating in the tissues. If you have several orchids in a specific area, perhaps it is time to get a small fan to run through the day. This can often prevent heat related issues, and increase growth by allowing faster transpiration. 

Hopefully this helps, and if it suggests further questions, by all means ask!

Sincerely,

Dennis

[yann....@gmail.com]

Hello Dennis,

Thank you very much for the prompt answer.

The black spots did grow slowly. I can't remember how long it took for the spots to be that large. The gray areas are indeed kind of bumpy and I could not notice any yellow margins. So while I'm a bit sad that the leaves will not recover, I'm quite happy that my Psychopsis does not seem to be infected.

When I mentioned that she was getting fresh air, I should have clarified that she's next to an opened window. I'm not sure how much air movement she's getting though. I'm now considering buying a fan. Is there a specific type/brand you would recommend? Not sure if there are orchid/plant specific fans available.

Thank you again for your help.

Best regards,

Yann

[dennis westler]

Yann:

 

I don't really have any specific recommendations. But I have found over the years that it pays to get at least a mid-price one rather than the cheapest ones. The cheapest onestend to get noisy and fail quickly if run all day or 24/7. It need only be a 6"-8" size. You can look through greenhouse supply websites, but most of the greenhouse fans are intended for wall mounting, and not really appropriate for home use.

 

Sincerely,

Dennis