If, as seems likely to me, like this:

(Image courtesy Tmaq97)

They are Eriosomatinae (woolly aphids] rather than whiteflies. They can be dealt with fairly easily. Those that don’t just wash off can be sprayed with 'horticultural' soap (that is, not a detergent) and, where available, neem oil.

These insects fly/are blown around in the atmosphere. Your plants should be salvageable and I'd not bother with a mesh or moving indoors. Depending on where you are more sunlight may be better overall and a mesh might do more to keep out their predators than the aphids.

If, as seems likely to me, like this:

(Image courtesy Tmaq97)

They are Eriosomatinae (woolly aphids] rather than whiteflies. They can be dealt with fairly easily. Those that don’t just wash off can be sprayed with 'horticultural' soap (that is, not a detergent) and, where available, neem oil.

These insects fly/are blown around in the atmosphere. Your plants should be salvageable and I'd not bother with a mesh or moving indoors. Depending on where you are more sunlight may be better overall and a mesh might do more to keep out their predators than the aphids.

ON THE OTHER HAND

If this (about the same size as the aphid above):

(Image courtesy D-Kuru)

(or similar but with no significant tail) then likely a mealybug (Pseudococcidae). Insecticidal soap will work against both aphids and mealybugs.