It is possible to get rid of spider mites... with some difficulty. So you should be able to save your plant. You need to treat with a miticide (not insecticide) at the proper strength and apply a follow-up treatment about a week after the first spray to eliminate any survivors. Excessively spraying insecticides (especially broad-spectrum systemics like Orthene) can actually encourage mite infestations because the insecticide eliminates all the beneficial mite predators while leaving the mites unscathed. Also, don't overdo it with the miticides either because mites can evolve resistance. Pest management can be a real pain.
I had problems with mites on my brugs this spring because of hot, dry weather. I tried the "organic" approach, which is to spray the backs of the leaves with a strong blast of water to wash off the mites. Not helpful. Next I tried spraying w/insecticidal soap - also didn't help. Then I ordered some Avid and sprayed with that, it wiped out the mites very quickly. I re-sprayed a week later to catch any survivors. So far the mites have not come back after the Avid treatment. I was wary of using the Ortho systemic (aka Isotox) because it's very toxic and has warnings about severe eye damage - just my luck I'd splash some on myself. Avid is targeted for mites - more of a precision bomb instead of a shotgun like the Ortho. I just wish it weren't so expensive. There is another miticide, Kelthane, that may be less expensive than Avid if you can find it. One downside of both Avid and Kelthane is that they kill only adults - the eggs can survive to hatch later and that's why the follow-up spray is needed. There is an extremely expensive product, Floramite, that kills both mites and their eggs. If I were a professional grower I'd use this but IMHO it's too expensive for the casual gardener.
