EEk! By my eyesight on the monitor, those look like either:

a) white flies,

b) the spent shells from aphids or some other leaf sucking insect.

Although they do not harm the plant anymore (the dried insect casings) the live ones will in those #'s! Wash off the plant with water to get rid of those and inspect underside of the leaves and in the nooks and crannies for live ones. You can use safers soap to kill them off, but I wouldn't go that route unless there are lots. The leaf you have pictured is wilty, I would prune that and other wilty ones off also. The washing off of the dead ones will allow you to access the progression of the lives ones if they are still around (new dead insect casings after you've washed all these off would indicate this).

Good Luck.

p.s. I'm not sure that the safer's soap would control white flies, you will have to do a search for that. I've only had them on occasion, and never in that quantity, and 'bothering' the plant by shaking them off several times through the weekend seemed to keep it in check (for me).

I agree that they are the cast of exoskeletons of aphids. Don't look anything like whitefly. Keep after the plant with strong sprays of water from the hose....enough to knock any live aphids off (do you know what aphids look like?) but never strong enough to damage the plant.

thank you for the diagnosis. i wiped what i could off. couldn't spray it off as the plants are in my tiny little balcony. i got some chilli/garlic spray for the aphids. i hope it works.