Spider mites are visible right? Cuz i can't find any annimal in the plant.
Next to that, i had some other animal in a plant of mine years ago, they spun a web in it and everything died, I could see those little critters.
For the humidity, i'm spraying pretty good with a normal plant spray, once or twice a day, depends on the room humidity.
I heard you could need some insecticide? For scales, or bugs, or anything else? And that sometimes a little bit of soap in the plantspray or a bit of spiritus in there (don't know the english translation for that)
would do wonders also?
But I'm a bit concerned with spraying soapy water on my plants, hardly seems organic or natural to me. I heard you could deploy bugs to eat the other bugs?
that sounds awesome, but a bit of hard job.