you may post it in garden clinic too

I can't see any spider mites (I actually haven't seen any creepy-crawly anythings that make me think they are building the webbing - apart from the moths) - though I've heard some spider mites can be microscopic. The small moths are a dark burnt orange almost brown color about the size of a fingernail (tried to get a picture, but they wouldn't sit still)... definitely not whiteflies (I only know that because we had a huge white fly infestation last year, so I'm very familiar).

Tonight, I will try another post in the garden clinic as well. Thank you for your help!

Watering sparingly might be you answer. Plants need regular and deep watering. I don't know of any bug that would cause your plants to dry out and die.

I just reread it. Sorry! Spider mites do cause webbing. I never saw their webbing that big. Spider mites are always microscopic. Invisible to the human eye.

I've had mites in patio areas and indoors, you can see them under leaves, the size of a pin point, the adults are more visible.

If you have mites, you will definitely be able to see them, look closely beneath a leaf that is still green.

I've not seen intense webbing from mites like this though, or this level of destruction.

May I suggest some type of fungus or blight? Flea beetles? Seems not too many insects favor herbs, they are too aromatic. The insect infestation might be secondary to another issue? How are your veggie plants doing? Anything weird there?

Looking at the pix again, it does look more like a mite, or other bug, try dish soap and water in a spray bottle. Not too strong, though. The soap will dehydrate and kill what-ever the bug is. It may not be too late!

Interesting enough, many of the other herbs are happy as clams. I've got a couple basil plants and some mint that I'm having to constantly chop back. I have a small rosemary shrub and some chives that all seem unharmed and perfectly contented in the same bed with they dying herbs and I recently planted some parsely and cilantro I grew from seed in nearby pots and they seem mostly fine also. There is a dwarf lilac bush in the same bed right next to the thyme and oregano which also seems largely unharmed, though I have noticed a little bit of browning at the tips of some of the leaves (nothing to cause me any serious alarm). The little moths remain and I took a much closer look at the webbing and still can't see any insects. Maybe I need my eyes checked!

I will try a little dishsoap tonight to see if that helps. I may just dig up the oregano and start over with that one - or maybe just collect the seeds. The oregano comes up like a weed all over the yard - I can probably just dig a healthy one up and move it.