23 March 2004
Mosquitoes are more than just nasty pests, they are disease vectors which spread some of the worst inflictions known to man - Malaria, Yellow Fever, Encephalitis, Dengue (Breakbone Fever), West Nile Virus and a host of others. In the United States, most areas are free of many of these diseases because of good public health and infrastructure. However, in a disaster, these protections could be lost and we would again be faced with these scourges.
Although pesticides can kill mosquitoes, this article will deal with non-pesticide mosquito control techniques because in order to kill enough mosquitoes to make a difference, most of us do not have the equipment or funds to spray enough of it, or to place enough larvacide bait, to make a dent in the population.
Non-Pesticide Mosquito Control
As good as pesticides are they cannot control mosquitoes by themselves. In fact, pesticide spraying or larvacide baiting are only a small part of controlling mosquitoes. Walter Reed, a famous army physician who helped control Yellow Fever in Panama during the construction of the Panama Canal, found that by draining swamps and stagnant water, the number of mosquitoes could be controlled. While we may not be able to drain swamps, we can certainly take steps to reduce stagnant water around our houses.
One of the most important things you can do to reduce the number of mosquitoes around your residence is to rid your area of breeding areas. Mosquitoes need water and food to breed. By getting rid of old tires and emptying stagnant water containers, you can cut down on the number of mosquitoes.
The following steps can make a significant reduction in the breeding areas around your residence:
- Mosquitoes need water, primarily still or stagnant water rich in organic matter upon which mosquito larvae can feed. Among the most common locations for this habitat are the saucers gardeners frequently place under potted plants, especially on decks and patios. One option is to remove the saucers altogether, or at least dump them every couple of days.
- For balcony and rooftop gardeners, self-watering containers have become increasingly popular. However, the reservoir beneath the container can breed thousands of larvae. As most of these containers cannot be emptied, an alternative is to tape over the access slot or hole used for filling the pot. This will keep out adult mosquitoes and trap existing larvae inside. Any other containers around the garden, such as watering cans, vases, buckets and wheelbarrows, also should be emptied and either stored indoors when not in use or turned upside down.
- For gardeners who like to root cuttings in jars and bottles outdoors, emptying the container and refilling it with fresh water every couple of days is advisable. Fresh water will encourage rooting and help eliminate mosquito larvae.
- Dripping outdoor faucets should be fixed immediately, both to conserve water and prevent puddles from developing and providing habitat. Also check on rain gutters and downspout areas, especially if you use corrugated plastic pipe to divert water across your lawn. Cover rain barrels with a fine mesh, such as window screening, to keep out mosquitoes. And make sure air conditioning units are not creating puddles as they drain condensed moisture.
- Some yards have natural depressions that can form impromptu ponds or bogs during rainy weather. Correct such areas either through grading, which can be expensive, or by creating natural garden areas with moisture-loving plants that can take up excess water and convert it to flowers and foliage.
- Ornamental ponds have grown in popularity, thanks to easily available and inexpensive pond liners and supplies. If the pond is stocked with fish, any eggs or larvae will be consumed readily. Aerate, filter or add fish to ponds merely hosting water lilies or other plants, or nothing at all. Even a simple dollar's worth of goldfish will control mosquito populations. Maintain ponds without electrical access with any one of several models of solar-powered pumps and filters.
- One unfortunate side-effect of public concern with West Nile Virus is that people are dumping or removing birdbaths. Empty and replace the water in birdbaths every two to four days, both to prevent the spread of avian diseases and to eliminate breeding areas. But removing birdbaths altogether can actually prove a hardship for smaller songbirds, like goldfinches, who easily overheat in summer conditions and require safe havens to cool off, especially as natural water bodies are becoming more scarce.
- In addition to typical garden areas, address a number of other mosquito breeding locations. A basic rule of thumb is that if it can hold water, it can breed mosquitoes. Tarps draped over woodpiles or lawnmowers can provide depressions that quickly become mosquito pools. Empty them immediately and rearrange the tarp so that it sheds rainwater. Tarps or covers over pools may keep out leaves and debris, but rainwater settling atop the tarp becomes prime mosquito habitat. A pump may be necessary to drain pool covers.
- Wading pools, however small, can invite mosquito activity. Empty them after use and store them on their side, or deflate them. Simply turning the pool upside down will only provide a smaller catch basin for rainwater.
- Watch out for water captured in uncovered trash cans or upturned trash can lids. Consider drilling holes to facilitate drainage. Recycling containers left outdoors also can trap water, as can bottles or cans left in the blue bin for more than four days. Again, consider drilling holes in the corners and handles of bins to ensure proper drainage at all times.
Some of this information was provided by the Maryland Department of Environmental Protection.
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