My parents get a lot of mosquitoes in their garden during the summer. We've tried torches with citronella additives in the oil, but this has not been effective.
I don't want to install a UV-based insect killer, as I don't want to kill non-biting insects.
I've seen some devices that purport to attract the mosquitoes via CO2 (which should only attract biting insects). However, these seem to be very expensive with substantial upkeep costs.
How well do these devices work when compared to other area methods such as citronella, area sprays, etc?