Mosquito Prevention

Mosquito Facts

  • Standing water is required for mosquitoes to develop.
  • In warm weather a mosquito can hatch from egg to adult and begin biting in as little as 7 days.
  • Mosquitoes do not develop in grass or shrubbery.  Adults rest there during warm daylight hours.
  • Only female mosquitoes bite to obtain a blood meal. The male mosquito feeds only on plant juices.
  • The female mosquito may live many weeks during the summer and may survive through the winter in order to lay her eggs in the spring.

How to Prevent Mosquitoes from Developing

Eliminate all standing water where mosquitoes lay their eggs and larva develop.

  • Destroy or dispose of cans, buckets, plastic sheeting, old tires, and other containers that collect water.  Do not allow water to accumulate at the base of flower post or pet dishes for more then 2 days.
  • Cesspools and septic tanks:  seal and cover openings so no adult mosquitoes can get in.
  • Ponds: Remove excess vegetation.
  • Irrigated lawns and fields: avoid over watering and eliminate standing water.
  • Bird baths: change water frequently.
  • Watering troughs: Dump and change water weekly. Eliminate standing water around the trough.
  • Open ditches: Drain to stream channels, underground systems, or other outlets. Remove obstructions and vegetation
  • Used tires: store indoors or dispose of at an approved location.
  • Swimming or wading pools: empty or cover tightly when not in use.
  • Water under house or in basement: drain or pump out if possible.  Treat as required.
  • Roof gutters: clean frequently to remove blockage.

Preventing Mosquito Bites

Mosquito prevention is both a public and private responsibility.  The Mosquito Control District’s policy is to control large populations of mosquitoes, but it is impossible to eliminate mosquitoes entirely.  Individuals will find it necessary to use their own prevention methods to protect their family from mosquito bites.

  • Use Mosquito repellents with ingredients containing DEET. Read and follow label instructions carefully.  Use caution if applying repellents to small children.
  • Cover doors and windows with screens if they are going to be left open during mosquito season.
  • Wear long pants, loose fitting long-sleeved shirts and socks when working outdoors.
  • Cover infant carriers with mosquito netting when taking babies outdoors.

The Mosquito Life Cycle


The common mosquito lays a mass of eggs on the water which float like a raft.  Each raft contains 100-400 eggs. The eggs hatch in a day or so into larva.


The larva, or “wiggler,” comes to the water surface to breath through a tube called a siphon.  It sheds its skin or molts four times during the next several days.  It grows rapidly between molts.  On the fourth molt it turns into a pupa.


The pupa or “tumbler,” cannot eat.  It breaths through 2 tubes on it’s back.  The mosquito grows inside the pupa and in approximately 2 days, when it is fully formed, it splits the pupa skin and emerges as an adult to complete the lifecycle.


The newly emerged adult rests on the water surface until it is strong enough to fly away and look for food.

You can prevent Mosquitoes from Developing!

When you have located every water source on your premises that might be producing mosquitoes you can:

  • Drain, empty, fill or seal off the water source.
  • Contact The Cowlitz County Mosquito Control district if the source is too large for you to deal with.

Whether you live in the country, city or suburbs, you may be bothered by mosquitoes.  Besides being annoying pests, some mosquitoes can transmit certain diseases to man and domestic animals.  If you know something about where mosquitoes lay their eggs, how they live, and what can be done to prevent or control them, you will be able to reduce the number of mosquitoes in and around your home.