there’s a machine which takes a 20lb propane cyl, & attracts 'em by flashing-lights & CO2, & it captures only mosquitos, unlike bug-zappers, and it can harvest a stunning amount of the things.

You need to replace the hormone attractant … capsule, or whatever it should be called, monthly ( that is where they get their recurring-money from, and it does make a big difference ).

Be selective in your culling of the local insect-population, as the entire ecology around you gets altered by the action, eh?