The only things that work around here are the thermacell repellents (they have a little butane fire that evaporates stuff off a mesh pad). Their effect seems pretty localized in time and space, but I wonder what's in them, and how problematic it is.

Yep, its clever how well chemical companies have sold us general poisons as being highly specific to certain plants/insects/animals.

That's not to say something can't work better on one particular type of biotic, but its still harmful to the others as well.

Mosquito dunks and clear standing or pooling water.