Remove Standing Water To Keep Mosquitoes At Bay

November 14, 2005

UNIVERSITY PARK, Pa. -- The Itch Of A Mosquito Bite Is One Of The Biggest Nuisances Of Summer. But You Can Reduce Your Chances Of Being Bitten -- And Help Keep Mosquito Populations In Check -- By Taking A Few Simple Precautions, Says An Expert In Penn State's College Of Agricultural Sciences.

"Ordinarily, mosquitoes are little more than a mild irritant," says Steven Jacobs, extension entomologist. "But because they can transmit diseases to humans and pets -- such as West Nile encephalitis, eastern equine encephalitis and canine heartworm -- you should take steps to avoid being bitten and to eliminate mosquito breeding areas."

Mosquitoes breed in standing water. Only female mosquitoes bite, according to Jacobs. "In most cases, the female must have a blood meal before laying eggs," he says. "The females' persistent search for blood brings them into houses and yards, where they may become annoying pests."

Many mosquito problems can be traced to containers of water around the yard, such as children's toys, pots and cans, tire swings, animal tracks and clogged rain gutters. Neighborhood breeding areas can include construction sites, trash dumps and cemetery urns or planters. Most mosquitoes remain within a half-mile of where they hatched, but some can fly many miles. During warm weather, mosquitoes can breed in any puddle that stands for more than four days. "The most effective way to control mosquitoes is to eliminate standing water," says Jacobs.

He advises homeowners to:

  • Remove old tires, tin cans, buckets, glass jars, toys and other water-catching objects.
  • Tightly cover rain barrels to prevent egg-laying.
  • Change water in bird baths by flushing with a hose at least once a week.
  • Fill tree holes with sand or cement or drill holes to allow drainage.
  • Keep rain gutters clean and free of obstructions.
  • Drain excess water from flower pots.
  • Keep swimming pools covered when not in use.
  • Turn over wading pools and wheelbarrows when not in use.
  • Empty accumulated water from boats and cargo trailers.
  • Clear aquatic vegetation from around the edges of ponds to allow fish to feed on mosquito larvae and pupae.

Jacobs says mosquitoes should be excluded from buildings by keeping windows, doors and porches tightly screened. "For mosquitoes inside the house, use a fly swatter instead of an aerosol spray," he says.

When going outdoors for an extended period of time, insect repellents can provide protection from mosquito bites. "Repellents can protect for up to five hours," says Jacobs. "But because people vary in their attractiveness to mosquitoes, the effectiveness of the repellent may depend on the individual."

Before using a repellent or insecticide, be sure you thoroughly read and understand all directions and cautions on the product label, Jacobs warns.

For a free fact sheet on mosquitoes, contact the nearest county office of Penn State Cooperative Extension, or visit the Web at


EDITORS: A printable infographic to illustrate this story is available for downloading at

Writer/Editor: Chuck GillOffice: 814-863-2713

Last Updated March 19, 2009