Orange/brown round spots on leaves

[agustinfranco]

Dear all:

There are these round spots that are orangy-brown on my N. veitchii H/L leaves and I wonder what they could be??
I look forward to anybody's reply.

Agustin

 

[lithopsman]

They don't look like anything bad, may be the "sunscreen/sunburn" that some neps with thick leaves are said to get, or it could be a fungus that I think is called Rust fungus or something similar... HOPE THIS HELPS!!

 

[Tony Paroubek]

Fungus of some sort is my guess. You can see the yellowish margin around it which is pretty typical for a disease organism that has damaged surrounding tissue from the point of infection.
Tony

 

[agustinfranco]

Hi Tony:

Thanks for your feedback. What type of fungicide do you recommend for neps?. Thanks

Gus

 

[swords]

I don't know your conditions but my N. northiana looks like this now because I swapped all six of the lights out for new ones (the old ones were over a year old) and the old leaves look terrible but the pitchers still look great and the new leaves are far larger and the pitchers should be too.

IF it's not a disease and just a sudden light intensity change similar to what my plants experinced I wouldn't worry about much other than being sure the humidity is sufficently high for pitcher development.

However, if you are growing under only a couple dim 40 watt flourescents in a sealed terrarium and have not recently changed the lights I would think of a disease of some sort. Possibly a fungal infection caused by water sitting in droplets on the leaves for an extended period of time can allow bacterias to create stains on the leaves. A lot of Orchids are experts at developing stain and Neps are second in line. If a simple fungal infection simply allow more air circulation with a little 1 1/2" -2" PC fan in your terrarium (blowing the wall not the plants-at least at first to acclimate them to air movement).

Just a few ideas.

 

[agustinfranco]

Hi Swords:

This plant is not in a terrarium but in a greenhouse with proper aeration. thus, it may be just too much light??. I applied a systemic fungicide and i'll wait to see the results. Thanks for your input.

Gus

 

[The Griffin]

I feel kind of dumb for saying this, but if they are the little spots on the leaves, aren't they nector glands?

Regards,

Joe

 

[swords]

It's quite likely those spots used to be nectar glands and the burning started there. They are fragile and will burn up very quickly with a sudden decrease in humidity and rise in heat/light. Especially if you were to spray the plants in bright hot conditions in an attempt to keep the humidity up and "wet the leaves" you will actually be washing the nectar away. The nectar keeps the actual glands themselves supple and "wet" sitting under the globule of nectar.

Here's a shot of my N. bicals leaf nectar glands secreting nectar:

And the underside showing the dark spots:

 

[Tony Paroubek]

Doesn't look like nectar glands to me because of the lighter tissue color around the dark center. Also because they are usually on the underside of the leaf and the spots look to be on the topside here.

I doubt it is burn from moisture droplets getting hit with sun in this instance.

I am not a pathologist but it looks pretty minor and is most likely something like Botrytis from excess moisture. I would only be concerned if:

The existing spots are getting larger.
Or
There are more spots showing up.

Tony

 

[agustinfranco]

Hi all:

Interesting questions!!. I hope i have interesting answers!!.

First of all, the spots go right through the leaf, not just on top.

No they are not growing, they just remain the same size. One curious thing though: the edge of the leaf have the same spots, but cut in half, like half circles!!.

Older leaves and newer leaves seem to be free of these spots so far!!.

If you have more questions, i'll take another picture later.

Thanks

Gus