Mosquito Management and Control

Mosquito Management and Control

James V. Robinson, Professor and Extension Entomologist
Jimmy K. Olson, Professor, Dept. Of Entomology, TAMU

Mosquitoes often make life miserable for humans, poultry and livestock. When temperatures remain at 70 degrees or above, mosquito development in pools of standing water soars. They are vectors of important human and animal diseases and may need to be controlled either through individual or community efforts.

In cities, resident cooperation and city managed abatement programs are essential in controlling and managing mosquitoes over a large area. Individuals who live in the country, either on large farms or small home sites, are largely responsible for the control of mosquitoes on their property.

Approach to mosquito abatement focuses on two areas: 1.) suppression of mosquito populations capable of vectoring or transmitting disease agents; and 2.) education. Cities often work with universities and the Texas Department of Health to monitor mosquito populations for the presence of diseases viruses. If these viruses are detected, public announcement of the detection is made for an area and often area wide abatement measures are placed into effect.

What can you do?

There are many steps that everyone should take to reduce mosquito populations around their home. Stagnant water pools are ideal breeding sites. These pools can be formed from rain water runoff or from irrigation runoff. Controlling or eliminating this runoff is one of the ways everyone can help in mosquito abatement. The more people are involved the greater the amount of control.

Mosquito species are very particular in their breeding sites. The reduction, elimination or treatment of these various sites are the best and most cost-effective means of abatement. Populations of floodwater, woodland, artificial container and stagnant water breeding mosquito species may occur in any part of the state. While most of the species are just a nuisance, stagnant water breeders pose the leading health risk. Nutrient rich, stagnant pools of water are the preferred breeding site for the Culex species. Culex mosquitoes are a major transmitter of encephalitis viruses.

Guidelines for abatement of stagnant water breeding mosquitoes

  1. Do not encourage the gathering of birds on your property since they are the source of encephalitis viruses. The Culex species responsible for transmitting St. Louis (SLE) and western equine (WEE) encephalitis viruses normally feed on birds and only occasionally on humans. These viruses are transmitted to humans when humans, infected birds and the virus-carrying mosquitoes are in close proximity to each other.
  2. Eliminate all low areas that allow water to collect and stagnate. If total elimination is not possible then the areas need to be treated with available 'over the counter' larvicides. When used properly the products will halt mosquito development before adults can emerge. The most convenient products are 'dunks' or 'toss-its' which contain Bacillus thuringiensis var. israelensis (Bti). Bti is an environmentally friendly, natural, non-polluting, bacterially produced chemical. Large bodies of water, such as ponds, generally contain fish and minnows that keep the mosquitoes in check. Introducing fish and minnows into ponds or landscape pools is a good way to control mosquitoes.
  3. Reduce or alter watering so that no runoff is produced. This not only saves you money but helps eliminate major breeding sites as there is no runoff to collect and stagnate in drainage ways.
  4. Do not allow water to stand in potted plant saucers, pet bowls, wading pools or other water holding containers for more than three days. Changing the water every three days will eliminate this breeding site.
  5. Tightly cover or treat rain barrels (fish may also be placed in these containers).
  6. Do not allow water to collect in rain gutters. Clearing these of leaves and debris that tend to hold the water preventing it from discharging will eliminate gutters as a breeding site.

Nuisance Floodwater Mosquitoes

Floodwater species become a problem seven to ten days after a rain. Higher water flow and water collection in normally dry areas stimulates egg hatch and development of these mosquitoes. After developing into adults, floodwater mosquitoes are generally only a nuisance for a week or two because of their short life span. However, many species can cover twenty miles or more in search of a food source. Local floodwater species usually come from the flood plains of nearby creeks and rivers, roadside ditches and other area drainage ways and flooded agricultural land.

Wood and floodwater species often utilize cavities in trees that can receive enough rainfall or water from sources such as sprinklers as breeding sites. The adults of the woodland species emerge and become a nuisance in a similar time frame to floodwater species.

Artificial container floodwater mosquito species prefer such items as jars, cans, tires or any other item that can hold sufficient water long enough for breeding, usually longer than three days. These mosquitoes are frequently a major source of backyard annoyance in urban areas. Adults tend to remain very close to their breeding sites so removing these containers is a good control method.

Prepare to live with nuisance mosquitoes

  1. Expect population growth of floodwater species seven to ten days after rain. Try to schedule outdoor activities away from early morning and late evening as these are the major feeding times for mosquitoes. Use repellents if these activities cannot be rescheduled.
  2. Do not use 'bug zappers' as mosquitoes use light to navigate. Once a food source is detected near a light, the light is then ignored and mosquitoes concentrate on the food source.
  3. Remove all trash, jars, cans, bottles, tires and all other items that can collect water and provide a breeding site. Keep rain gutters free of trash and standing water. Keeping grass and weeds mowed will also reduce breeding sites as water collecting in depressions will be exposed to wind and sun and dry quicker.
  4. . Fogging or spraying garages, sheds, shrubs and grassy areas with an approved adulticide will help eliminate mosquitoes resting in these areas. There are many products approved for use by homeowners against adult mosquitoes. These products are available at local farm supply and retail outlets.
  5. Inspect window screens and screen doors for gaps and areas in need of repair. Make sure these fit properly and exclude mosquitoes from entering the dwelling.

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Last modified: July 15, 1998 by Andrew Perrone