I got nothing.
From the underside shots it looks like pests, eggs from what my old eyes can see. Normally those no pest strips work pretty decent at keeping pests at bay but once they have a foothold they don't work too well. BTW, don't breathe that crap.
Nothing flying, nothing comes off with shaking, how about on the underside of those leaves, those small spherical things, is that not eggs?
Are you growing organic? Like true organic with living soil? You said it is affecting the lower leaves which makes me wonder if something came out of your soil if you are in organic. If it is soil, was it stored, cooked or spend any time outdoors?
One of four plants is nothing new. When I have a pest attack I generally see it on one plant first and if I don't get it under control quick it will begin spreading to other plants. Rarely do they attack all at once, matter of fact, I haven't seen it. Once the plant is dead or the pest population is so great the single plant won't support them they will begin moving.
If it were me, I would get insecticidal soap, neem and azamax. You already have the soap. Spray insecticidal soap, a few days later spray neem, a few days later spray azamax. Also make a soil drench with your neem oil. Once the grow is over, get everything out of the tent and spray everything down with a 10% bleach and water solution. Make sure you have plenty of air circulation, it will burn the hell out of your lungs but will kill everything in sight.
I don't think it really matters what kind of pest it is, more important to get rid of them. Oh, and by the way, make sure you spray the underside of leaves, that is where most insects lay their eggs and that is where you want to target.
good pics JT, thanks! ...
... I'm not harping about thrips alone, they're just the best fit so far... but there are all manner of sap suckers out there, just less common....
