Yellowish lines and curves on leaves

[Tilly]

Hello Everyone,

This is my first post and I am hoping that you can tell me what is wrong with my orchids!

I have fourteen plants and they are all suffering, even the two that I keep apart from the other twelve. Several leaves on each plant have the problem.

I have tried to take a close up picture of the underneath of one leaf, which seems to have regular, almost geometric shapes. This makes me think it is some sort of pest?

Also, the edges of some of the leaves seem to have a sort of "curve" (not very easy to explain)

They have had this problem for a few weeks, but it seems to be spreading - but only on the orchids. I have a large collection of succulents and so far so good.

Any help VERY gratefully received

Many thanks

Tilly xx