greenhouse under attack!!!

[dukejenn]

Hi everyone! I am so depressed. I think my greenhouse is under attack by I don't know what...I suddenly found out these past two weeks that my orchids are sick, first the phals then next the dendrobiums, then next my sanderiana, now even my cattleyas!!! I can't really identify what's happening thou i searched for infos but still i found different things in my plants. Please help!!! I really do appreciate any advise. Thanks is advance. I'm posting pictures