Help ID what this is.

[angela]

Hi everyone, I,m back after quite a while, and I immediately need your help.
Yesterday I visited an orchid nursery where the owner rents his plants to hotels and villas and after one Tourist season he sells off the plants and brings in a new lot for the next season. the plants are usually healthy and only need some care or re-potting, and they are sold rather cheaply.
To my horror those I bought yesterday (I only noticed it when I got Home) the leaves are all heavily mottled. These are Dendrobium plants. The blooms are quite healthy and so are the buds.
Needless to say I can not find a place far enough away from my collection to put them until I find out what's wrong.
Please have a look and help me.
Angela