A neglected swimming pool is only partially filled with water while another is completely full. Which one produces more mosquitoes? If you guessed the pool with more water produces more mosquitoes, you’d be in the majority.
Let’s be clear: both pools can produce more than 1 million mosquitoes and affect people up to five miles away. Neglected pools are especially attractive to the kind of mosquitoes than can transmit West Nile virus. But, the pool with less water is the one capable of producing more mosquitoes.
Mosquitoes must breathe air so they stay mostly at the water’s surface. It’s not the volume of water so much as the amount of surface area of the water that enables more mosquitoes to thrive. But, that’s not all. Other factors, such as the amount of food available to the mosquito larvae enable them to thrive. The shallower the water, the more concentrated the algae and other available food. Also, less water results in less water action–less waves–since the water is more sheltered from the wind. Mosquitoes prefer still, not agitated water since the eggs are fragile. Even more to the point, less water and less agitation makes survival of the young mosquitoes easier since they spend less energy swimming in order to breathe, eat, and fight wave action.
Maintaining swimming pools is the best way to fight mosquitoes. Chlorinate and filter swimming pools regularly or ensure that all the water has been removed. Even a couple of cups of water at the bottom of a pool can be a significant mosquito source. Use Mosquito Dunks to treat smaller amounts of water. In some cases, mosquitofish can be placed in neglected swimming pools as an intermediate solution. Mosquitofish are available free from our District for Contra Costa County residents. Please contact us to learn more.