I live in humid, subtropical Florida where mosquitoes are very common and I grow numerous indoor plants that all sit in decorative pots with pebbles and a small amount of water. We rarely get mosquitoes in the house; on occasion one will fly in when the door is open to let the dogs in or out but a quick swat takes care of the mosquito.
I've heard some people talk about placing "mosquito dunks" in their plant saucers, which is said to be non-toxic, kills the mosquito larvae and supposedly will last for about a month. I've never had the need to use them so I can't attest to their effectiveness.
