Industry News

Why mosquito populations in major cities continue to increase

Austin M. Frishman, Ph.D.

People usually associate mosquito bites with being outdoors or being in the countryside. When people go fishing, hunting or attend outdoor events, they often apply mosquito repellent. So why do heavily populated cities such as New York continue to deal with increased mosquito populations?

There are several reasons, but only one is a natural event. The rest are created by humans:

  • Green rooftops include ponds and plants, which introduce mosquito breeding sites. Migrating birds, which carry viruses, spend time on rooftops. Once mosquitoes bite these birds, mosquitoes can potentially transfer the virus to humans

  • Bromeliad plants, which don’t require soil to survive, have become popular for commercial office buildings in lobbies, meeting rooms and offices. The leaf structure catches water, which attracts mosquitoes to deposit eggs. The mosquito larvae live in these small pools of water and their fecal material serves as food for the plants.

  • While huge indoor atriums look great and add to the value of a building, they also contain ponds and plants that draw mosquitoes.

  • Some smokers prop open exit doors and windows, allowing mosquitoes to fly in.

  • Air conditioning units in windows should be installed tightly, but most are not. The drip pan catches the condensation water on the exterior, which can draw adult mosquitoes indoors.

  • Sump pumps in basements and sub basements accumulate water, creating ideal spots for some mosquito species. Inspect sump pumps to see if they work and ensure the water is appropriately treated.

  • With mandatory recycling in most areas, empty soda bottles can sit for a long time and accumulate rainwater. Since mosquitoes need very little water to survive, they are attracted to recycling bins.

  • In New York, some energy companies bury electrical control vaults under sidewalks in front of tall buildings. These vaults have sump pumps that mosquitoes can reach.

  • As cities grow older, utility lines deteriorate and form puddles underground, creating breeding sources for immature mosquitoes.

  • Hurricanes can cause devastating damage to cities. Flooded basements, sub basements and subways, as well as broken screens and windows, can give mosquito populations opportunities to grow.

  • Visitors from other countries where a particular mosquito-borne virus is prevalent can transport the disease organism through their blood or organs. These individuals often enter large coastal cities first.

  • Finally, we have the unknowns of the future. For example, a new garbage truck might be designed without thinking about mosquitoes, creating new breeding sites in thousands of garbage vehicles.


The challenge for pest management will never cease. Neither will the importance of defending our customers’ properties and well-being. Next time you’re on a mosquito service call, consider these scenarios as you work to determine the source of the increased pest population.

To find out how to start and/or improve your current mosquito management programs, contact your local Syngenta territory manager.

To receive articles by Dr. Austin Frishman, advanced pest management information and more, subscribe to our emails.

© 2022 Syngenta. For Life Uninterrupted and the Syngenta logo are trademarks of a Syngenta Group Company.


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