thin spider web on my orchids

[rbarata]

Originally Posted by Orchidtinkerer

you have spider mites.
Sometimes they can be too small to spot with the naked eye but I can see the damage to the leaves and tiny black droppings too.

I also though about that but inside a terrarium with a humidifier that probability is low.
What are the humidity values?
That plant is inside the terrarium for how long?

[flipp]

humidity is always between 75-85% and the plants which have the webs are in there for at least 6 months

[Orchidtinkerer]

Originally Posted by rbarata

I also though about that but inside a terrarium with a humidifier that probability is low.
What are the humidity values?
That plant is inside the terrarium for how long?

that makes the probability 3 times higher. Mites hate airflow, drafts and low humidity. IT dries them out. Provide a warm humid terrarium and they explode (in numbers).
It could not be mites but to use the argument that they are living in their preferred environment as the probability being low is not a good argument imo.

[rbarata]

Originally Posted by Orchidtinkerer

that makes the probability 3 times higher. Mites hate airflow, drafts and low humidity. IT dries them out. Provide a warm humid terrarium and they explode (in numbers).
It could not be mites but to use the argument that they are living in their preferred environment as the probability being low is not a good argument imo.

OT, I think you are not correct. Mites thrive in low humidity. One way to control their population is to increase RH.

[Orchidtinkerer]

ok, well, then the OP has mites that haven't exploded in numbers yet because they are being kept under control by high humidity. Either way mites are horrible and should be erradicated not just controlled. There are certain spiders that are completely harmless that can make webs like those too though but I would not take the risk myself and its the damage to the leaves that is more important than the webs which could even be remnants of a mite presence that died because of high humidity. We will have to wait for the OP to give an update.