'Little white spiders' doesn't mean much except that you also say they are making webs on the plants. Webs + spiders probably means that they are setting up for a buffet of bugs. You may have just 'squashed' your pest control team girl!!!!

You also mention Aphids, if you have herbs you probably also have spider mites and white fly plus some scale insects which you may have not seen yet.

Where I live I have ants, spider mites (both kinds), scale, thrips...just to mention a few things. I also have a very hungry pest control team of gecko's, spiders, other lizards and a few other things. I've only (occasionally) used a little bit of soap spray when the scale got out of hand on the Flowering Apricot trees and the Kumquat. I'd let the spiders set up again and just watch them (sort of like reality tv) to see what happens.

Bob