Paphiopedilum Brown Spots and Darking of Leaves

[KristofferNgo]

Hi

I acquired a Paphiopedilum Ciliolare last March 26, 2021. I found out that the plant hand fungal problems. At first, there were black spots and yellow rings around it. I sprayed fungicide and observed.. later on, the fungal spots started spreading. I decided to cut the leaves with the fungal problem. The plant has spikes and I know that the old growth transfers nutrients to the newer growths, which are still either babies or have flower spikes. When I cut the leaves, a day after, I found out that some leaves from the old growths were turning dry and dark (refer to picture). Is this normal? Could this be due to magnesium deficiency of the old growths since they're transferring their nutriets to the newer growths? Below are pictures with descriptions.

Imgur: The magic of the Internet

I'd also like to ask if these brown spots on my Paphiopedilum Philippinense are not fungal problems? The plant was acquired 2 weeks ago and came along with it. They don't seem to be spreading. Below are the images.

Imgur: The magic of the Internet

I grow them both Paphs outdoors. with bright light together with Phalaenopsis... average temparture is high 28 degreec C at night to 31-33 in the morning and afternoon. They get direct light around 30 min. - 1 hour each day (around 10:30am-11:30am). It's summer here so it can be really hot. Come rainy season, which is June, temperature can significantly drop, which could be ideal for Paphs. Don't want to move the plants anywhere, but I think they could adapt to the environment. The Phals were able to bloom on the same spot.

Hope you guys could help, thank you.

[Ray]

It’s kind of hard to tell from those photos, but the mottled-leaved plant simply looks like it is losing an old growth. If anything, I’d bet on a bacterial infection, not fungal.

I see nothing on the other plant.

Obviously I can’t be certain, but that potting medium looks awfully dry, when paphs prefer even moisture.

[KristofferNgo]

About the Paph Ciliolare, I think that's what I'm thinking too... it's just losing old growth...

On the Paph. Philippinense, the spots look like freckles... it has a lot of it.. it's quite small, but I did take close-up pictures.. the spots are not at the center of the pic, but you can see them on the leaves... The medium looks dry, but when you dig a little deeper, the medium is moist

By the way, I read one of your threads about Humic Acid... do you think it's a good idea to use both Humic Acid and Fulvic Acid together with the fertilizer? Of course, I won't go overboard with them.

[Ray]

Originally Posted by KristofferNgo

...do you think it's a good idea to use both Humic Acid and Fulvic Acid together with the fertilizer? Of course, I won't go overboard with them.

Yes, I think it's safe, because my experience tells me they do little to nothing.

They're supposed to enhance nutrient uptake, and that may be advantageous in fast-growing plants, but it seems to have very little benefit - if at all - for slow-growing plants like orchids.