Dendriobium New Leaves not Opening

[crc092000]

Hello, I am hoping someone can shed some light on this problem. I am from Trinidad and we imported some Dendrobium Plugs from Thailand. The plants are now about a year old (blooming size- about 12 inches), and the top leaves are not opening. They are sticking together. If I do not open it every day the new leaves eventually rots.

Can anyone provide some insight into this problem?

Any suggestions would be appreciated.

Thank you,
Cherise.