Female mosquitoes can lay their eggs in any body of standing water, including in old containers and ditches. The eggs take two weeks to turn into mature mosquitoes that may become a nuisance around your home. Mosquitoes find manmade ponds especially attractive for breeding because such ponds don't usually have predator species that feed on the larvae. Removing mosquito larvae from your pond can effectively minimise the number of the pests in the area.
Introduce fish to your manmade pond to kill mosquito larvae. Purdue University recommends using mosquito fish (Gambusia affinis) for a pond that is not connected to natural waterways. Although effective in killing larvae, the mosquito fish can change habitat resources dramatically and may not be suitable for ponds connected to natural waterways.
Grow a plant or erect a covering to provide shade from the sun for your manmade pond during the summer. This improves the conditions for fish as higher temperatures lead to less oxygen in the water.
Clean the pond regularly, removing debris like grass, leaves and trash to prevent blockage. Grass and leaves may also add nutrients to the water, making the pond even more attractive for breeding mosquitoes.
Place a fountain, waterfall or another aerator in the pond to keep the water moving. Mosquitoes need standing water to breed, so agitating the water makes the pond unsuitable as a breeding site.
Apply a mosquito larvicide to the pond. Some larvicides you can use include Bacillus thuringiensis (Bti), Bacillus sphaericus, methoprene, aliphatic petroleum distillate and temephos. Follow the manufacturer's instructions closely.