Weird white powder and flies

I've noticed what seem to be fruit flies making a home inside the hydroton pots. I've killed most of them by hand, but was wondering if there is a foliar spray I can put on the plants to kill them or something plant-friendly to spray in the hydroton to kill them?

Also, not sure if this is related... In the pics you can see white, what looks like, powder. Not sure if this is nutrient buildup, mold, or eggs but when I smoosh it, it doesnt squish like eggs but is hard like nutrient buildup but weird since its on the leaves...

was wondering what the white buildup may be, maybe the fruit flies eggs or nute buildup?

also on the leaf in the bottom of the pic named unnamed-2.jpg you can see little dots or small / short lines(almost like eating marks, but dont go all the way through the leaf) on the leaves. I found one small catipillar and killed it weeks ago but now finding similar spots on other plants.. could these be catipillars or maybe more fly problems , i.e. the flies are eating the leaves, leaving white stuff and spots or if the three issues are completely separate?

example: on pic named unnamed-2.jpg you can see the white spot on the right (nute buid-up / eggs?), which can be wiped off, and little eating marks on the left.

also I've looked underneath the leaves and no little black dots / no spidermites so the white stuff is not a web...

looks like powdery mildew/mold to me

if its crusty it is dried residue. fruit flies are fungus gnats. gnatrol or whatever peeps are suggesting nowadays is what you need.

I would foliar feed just plain water rinse em off. you can get sticky yellow traps from amazon for gnats, if you wish to avoid chemicals.

mosquito dunks might be an option, ive never used em in hydro though

Thanks guys. I am using a foliar spray for the first time - Ocean Agro Dirt - and the white buildup / dried residue is on the hydroton too so maybe its just nute buildup(still weird since I've never seen any dry buildup on leaves). If it is mold it shouldn't be too hard to kill since I know how to handle that one.

I got another pic of the leaves and found one leaf with black dots on it. Again no black dots under leaves but this one plant has them on just this one leaf. I've had spidermites in the past which you can visually see but these guys are so small its hard to tell what it is. See pic one.jpg ... on pic two.jpg you can see more of the "eating" trails or whatever it is on other leaves that the small dots are not on...

those are bug turds, and the white dots look like thrip damage. where they sucked the juices.

you need to dip em if you can.

Thanks Velvet Elvis! A little research on Thrips show youtube videos with leaf pictures exactly like mine. I think, for the most part, this guy says use the same stuff you use for spider-mites. I can't dip the plants now because they are too big but I had spider-mites a few years ago and got plastic gloves and wiped down every inch of the plants with the stuff on the gloves and solved that issue.

I'll see if that works, thanks!