Looks like sunburn, to me. THe tiny spots around it would be where droplets of water lensed sun and the big patches were just outright burnt. -Cj

Ginger, You need to go to the American Orchid Society Web Site and find their culture sheets for Nobile type Dendrobiums. There are other web sites that also offer detailed culture instructions for these plants. Nobile Den's. grow a bit differently from other orchids, and you will have to conform to their wants and needs to get them to bloom. First, be absolutely sure you are rid of the scale. Scale suck the juices out of the plant, and are difficult to get rid of because most contact insecticides can't get through the scale to the bug. The scale is probably not what caused the leaves to drop.....That happens to the leaves every year. Next, any of the old canes on your plant that are shriveled, and DEAD, can be removed. Sharp sterile blade, and cut them off at the base. Be sure they are completely dead, because the old canes are storing nutrients for the plant as long as they remain alive. Now, growing the thing.....In the spring when new growth starts at the base of the plant...(Nobiles are prone to producing Keikis on old canes, and that's ok. Leave them on and let them bloom then remove them and pot up as new plants.....you need to really grow the plant. Lots of sunlight, water, and 30-10-10 fertilizer. You want those new growths to really grow big and healthy. In the early fall, the leaves will begin to yellow, and fall off the plant...normal..... At this time you should stop feeding the high Nitrogen fertilizer...use 10-10-10, or just stop fertilizing until spring growth starts again. If you are not growing the plant outside, it would be best take it outside in the fall. Let the plant stay outside until it experiences several nights of very cool temperatures....even a light frost won't hurt. When the weather gets too cold, bring the plant in and enjoy the blooms. When the blooms fade, reduce the amount of water you give the plant until new growth starts in the spring, then go back to the heavy feeding/growing of the plant. Once a cane blooms, its not going to ever bloom again. All leaves fall off in the winter. Bill

Wow, it is puzzling. It doesn't look like an ower-watering issue to me, but since we're not coming up with any more likely possibilities, then it is something to consider. This late in the year, it has likely stopped growing, even in Florida temperatures. Pothos tolerates drying out pretty well, so let the top couple of inches dry between waterings. How long have they been in that soil? Did they grow well all summer? If so, they might be a bit pot bound now, which can cause some dry spots in the soil, or some roots to become so restricted that they aren't able to draw enough water. It isn't the best time of year to re-pot, especially if something else is causing the problem, but you should at least check this. Can you pull the entire plant out of the pot with the soil and rootball intact? If so, a photo would help us. Check the root ball and medium for dry or mushy spots, for discolored or necrotic roots, for root parasites, crowding, etc. A few, small disrupted places in the root ball where you dig in to check the condition won't hurt it, even this time of year, and if it's very pot-bound, you can plop the entire thing into a larger pot of soil until the spring when you can do a better job or repotting, detangling, root-trimming, and so on. What parts of the plant are affected the most? Were the oldest/lowest leaves on each stem affected first/worst/most, or is the damage worse on the younger, more tender leaves? Are there any parts of the plants that aren't affected? When was it last fertilized, with what, and how often? (Do not fertilize it now- that's the worst thing one can do to a sick plant if the illness isn't due to fertilizer nutrient deficiency.) It might just be lighting, but the plant in the upper photo appears to have an overall yellowish pallor. That would support Tiffany's hypothesis of too much water. Also, I see a yellow leaf near the base of a stem in the second photo near that little sprig of Acacia or whatever it is that's taken root there. Some yellowing is normal, but check through the lower leaves for more yellowing. Too much water or nitrogen deficiency both tend to affect older/lower leaves first. Evenly yellowing lower leaves is more indicative of too much water or poor drainage, while yellowing that begins at the leaf margins is more often nitrogen deficiency. Other things can cause yellowing though, and that curious staining appearance isn't typical of either issue, so don't fertilize at this point. More photos wouldn't hurt: Entire plant Root ball free from the pot Close-ups of the "stains"

I've been growing orchids for at least ten years and I still get confused by info I find on-line. Unfortunately much of it often being contradictory. More of my two cents worth: your plant has a new pot, size should be OK for another year. Watch those escaping roots, as long as they stay nice and silver green in color with greener growing tips they are happy!!! Misting them with a hand sprayer will make them even happier . it will appreciate moving air from a nearby fan and bright light. Temps the same that you and I enjoy. Feed every week or two with a 1/4 strength plant food ( orchid food, IF available). These are ideal conditions for the plant. They will usually grow/bloom with much less than ideal conditions. Be careful to NOT let water sit in the crown of the leaves. If water splashes in there just blot it out with tissue. It's best to water/mist early in the a.m. If that will work for you, then excess water has time to evaporate. Relax and enjoy your plant, after all you've grown it already for well over six months!!!