A properly-designed pond will not attract mosquitoes, as mosquitoes prefer stagnant water to produce their offspring. Most backyard-ponds have constantly moving water, between the skimmer and the waterfalls/streams. Additionally, any mosquito larvae that manage to hatch will either be sucked into the skimmer or eaten by the fish. If your pond does not have a skimmer and/or fish, consider getting a pump and fountain combination. This should create enough water movement to discourage mosquitoes from visiting your pond.
