Remember this photo of my citrus from early October? I said that in a few months they would lose their leaves.
So when the large variegated one on the end began to do so about 2 weeks ago, I really didn’t even pay attention. All the citrus get scale every winter and I could see it recurring. So I figured between the scale and the unbelievably dim light that we have been having because of all the rain (but it’s still rain, not ice and not much snow, so I will take it, thank you very much!) it was just normal leaf loss.
This is a warning about what happens when you assume. Needless to say, it wasn’t normal leaf loss, nor was it due to the scale alone.
I am not even sure how I noticed: it might have happened in a rare sunny moment (because we don’t get whole sunny days).
I was watering and I noticed that the variegated plant was covered in webbing. Spider mites. So not only was that plant infested, but every other plant on the windowsill was infested–because spider mites get out of control very quickly.
Luckily I had a warm day to take everything outside to spray it off with an organic oil. I also washed the whole windowsill down and washed all the trays out.
But for the rest of the winter now,I will need to be vigilant about watching–& probably treating for spider mites.
Oh well. At least I won’t be bored.
Gardendaze 
Gads! Those are nasty! When I grew citrus back in the 1990s, mites preferred the mandarins for some reason. Not only that, but the preferred certain cultivars of mandarins to others! They also liked the Rangpur lime, which happens to be a ‘sour mandarin’. They got into the variegated lemon as well; but tended to not bother the ‘Meyer’ lemon much. I know that they could, but they had better things to eat.
This is why I am totally shocked. Scale yes. Spider mites? I haven’t had those in decades. And yes, they’re horrible and breed faster than rabbits. In the “insects ” portion of my houseplants lecture, I always joke that we know Stephen King isn’t a gardener. With some of the insect pests breeding habits, he’d have no trouble getting a horror novel written.
After all, the original X-Files had a show on flatworms. Ick.
Karla
Glad you were able to spot it eventually and I hope it’s under control and they don’t return for you!! I’m pretty new to indoor plants and haven’t had to deal with bugs yet, thankfully.
So glad to hear! Generally, the older the plant, the more susceptible to insects and diseases. But don’t borrow trouble.
Happy New Year!
Karla