I suspect my Cattleya orchids have the viral diseases based on the images from this website Images of Virus on Orchids.
Necrotic Spotting on Plant 1
CymMV viral disease on Plant 2.
How could I test for this? And in the meantime, should I cut off all infected leaves to save the plants and to prevent the diseases from spreading?
The big tan spot is sunburn. The others could be fungal diseases. As you alluded it's impossible to diagnose viral disease without specific testing. I've never used that. If you search Orchid Board you'll find other people's recommendations.
Have you had a look at the diseases page at the Web site of the St Augustine Orchid Society?
__________________ May the bridges I've burned light my way.
How could I test for this? And in the meantime, should I cut off all infected leaves to save the plants and to prevent the diseases from spreading?
Thank you,
Don't cut! The leaves are still capable of photosynthesis which the plant needs. And don't treat anything until you know what you are treating (Likely not virus, there are treatments for fungal issues but if the plant is just put in conditions where it's not too damp, the problem may cure itself... ) Do isolate suspicious plants from the rest of your collection. You can determine if the spots are spreading by putting a circle around them with a sharpie. If not spreading, then you're likely "in the clear" but do get some virus test kits. The dark spots could also be consistent with too much sun (especially if the flowers are dark) and that would be consistent with the sunburn.