Looks like spider mites or thrips, but since none of the new growth looks like thrips are at work, spider mites gets my vote.

Al

I agree... spider mites can very quickly devastate indoor plants if they're not eradicated or brought under control in a timely manner. I keep Schultz's 3 in 1 spray handy for just such infestations... it's an insecticide/fungicide/miticide all in one product.

I spray the infested plant liberally, and then follow up a couple of weeks later to kill any mites that hatch in the interim. I'm careful to include the undersides of leaves, as well.

Spider mites love a dry environment, so I mist my plants at least once a day. The majority of what I grow indoors are either bulbs or orchids... and I'm not entirely certain what might prevent the mites on Basil.

As far as a more natural, organic way to rid plants of spider mites... a bath in the kitchen sink with a tepid spray of water might help a bit... but other than that, I can't help. I'm afraid I rely on my spray for mites.

Honestly, it doesn't look like spider mite damage to me. My immediate first response is that it's a fungal disorder, probably exacerbated by being brought inside (where basil will never be happy, even in a sunny window).

Mites could certainly be present, as well, however.

Thanks for the ideas... I'm away from home for a week, so I suppose whatever is afflicting my basil will probably really mess it up while I'm gone. We'll see when I get back; I was really hoping I could get a few more months out of the plant, but I'll probably just have to wait until winter is over!

Quite honestly, unless you have a decent supplemental lighting setup, most annual plants won't be happy once brought inside for the winter.

Most of the plants I recently brought in are busy dropping leaves. The light intensity and humidity are just too different.