Mosquitoes – Control & Protection: Preventing West Nile Virus

Mosquitos are responsible for the deaths and illness of millions of people and animals through the transmission of diseases. Some of the diseases they carry include malaria, yellow fever, dengue, encephalitis, dog heartworm and the West Nile Virus. WNV is relatively new in the US and also infects our wildlife. People, horses, pets and wild birds have died from this disease.

Safety from West Nile Virus lies in eliminating whatever mosquitoes you can and in protecting yourself and your pets from those which survive and may carry disease. This article presents some actions you can take and some products you can use to prevent breeding, kill adult and immature mosquitoes, repel them from your property and your person, and keep them out of the house.

The products mentioned here have not been tested by the author, but have been included as examples of what is available. Testimonials for many of them can be found on their websites.

Preventing Mosquito Breeding

Eliminating the water in which mosquitoes breed is the preferred and primary method of control. Mosquitoes need water to develop, so lack of standing water means no mosquitoes.

Mosquitoes can breed in as little as a thimble full of standing water, so it is important to identify and remove as many sources of stagnant water as possible. Each source eliminated helps reduce the current population, as well as the numbers in future generations. Some of the things that can be done include:

  • Draining nearby ponds, small wet areas or containers where static (standing) water accumulates, or contacting local authorities for information on how to prevent or eliminate mosquito larvae from them.
  • Stocking ornamental ponds with fish that eat mosquitoes.
  • Filling in low areas in the yard and holes in trees that catch water.
  • Disposing of plastic containers, tin cans, ceramic pots, buckets or similar water-holding containers or covering them.
  • Covering trash containers.
  • Emptying standing water from old tires or discarding them.
  • Drilling holes in the bottom of outdoor recycling and trash containers.
  • Cleaning clogged roof gutters and spouts on a regular basis.
  • Changing the water in birdbaths, wading pools and pet dishes several times a week.
  • Turning over wading pools and wheelbarrows when not in use.
  • Keeping swimming pools, hot tubs and outdoor saunas clean and chlorinated or draining and covering them.
  • Keeping drains and ditches clear of weeds and trash so water will not collect.
  • Removing standing water from flat roofs.
  • Screening rain barrels and openings to water tanks or cisterns.

Larvicides – Mosquito Larvae Killers

If it is impossible to eliminate all sources of standing water, then larvae killers (larvicides) may be of help. Both chemical and biological larvicides are available.

Two biological products are Mosquito Bits and Mosquito Dunks which contain Bacillus thuringiensis bacteria that feed on mosquito larvae.

  • Mosquito Bits are small granules containing the Bti bacteria that are spread on the water surface. The larvicide granules gradually settle in the water where they are eaten by mosquito larvae. Mosquito Bits will give a quick kill, usually within 24 hours. A seven to fourteen day interval between applications is recommended. For longer term control, Mosquito Dunks can be used after applying Mosquito Bits.
  • Mosquito Dunks are 2 inches in diameter and 1/2 inch thick, with a small hole in the center. They contain the same larvicide as Mosquito Bits. The Dunks float on top of the water and will be effective for approximately 30 days. While floating, they slowly release the larvicide that settles in the water where it is eaten by mosquito larvae. Alternate wetting and drying will not reduce their effectiveness. The center hole can be used to anchor the dunks in place with a string or stake.

Another non-chemical larvicide contains mainly mineral oil. Sprayed on the surface of the water, it works by suffocating the larvae.

Mosquito Larvicide, available from Extremely Green, kills larvae and pupa stages of mosquitoes. It is designed for surface application to intermittently flooded areas, catch or sewer basins, ditches, stagnant pools and ponds. Containing(98%) mineral oil, it does not smear or deface the environment. Since mosquitoes can hatch in 5 to 7 days of warm weather, any exposed stagnant water should be treated. May not be sold in New York state.

Repelling Mosquitoes On Your Property

Garlic Barrier and Mosquito Barrier are two non-chemical products which use liquid garlic to repel mosquitoes. The active ingredient, 99.3 percent garlic juice, kills off mosquitoes in the nymph stage. Sulfur, which is also present in the garlic, acts as a repellent on the adults. Garlic juice has been used for over a hundred years on garden plants to keep insects away.

Garlic is absorbed through the pores of plant foliage and travels systemically throughout the entire plant. The juice doesn’t harm humans or pets, but can be deadly to small insects. A mosquito’s sense of smell is about 10,000 times better than humans. As long as they can detect the sulfur and garlic extract they will stay away from the sprayed area – for up to a month and more.

  • Garlic Barrier – A strong liquid garlic concentrate, dilutes in water and is sprayed on farm and garden plants to keep insects off. Greatly inhibits mosquitoes from staying in the treated areas. EPA registered. Odorless in minutes. Listed for organic farms by OMRI and CCOF. No chemicals, non-toxic. Some sources for Garlic Barrier are Gempler’s, Extremely Green and Ray Meeseman Co
  • Mosquito Barrier is a variation of Garlic Barrier. Mosquito Barrier kills and chases mosquitoes, ticks and fleas out of the yard and away from the house immediately upon spraying and keeps them out for 4 weeks and longer. Spray onto grass, shrubs, flowers and any trees in the area. Safe for children, pets and plants.Mosquito Barrier is also a larvicide. When mixed with canola oil or soybean oil, it coats standing water with a very thin film of natural oils. This oil suffocates the mosquito larvae which are developing in the water.

    Mosquito Barrier kills adult mosquitoes on contact, the garlic coated plants keep mosquitoes out of the area and it suffocates any mosquito larvae in standing water.

    Some sources for Mosquito Barrier are Extremely Green and Ray Meeseman Co. It is also marketed as Victor’s Mosquito Barrier in many hardware and garden centers and Mosquito Barrier Yard Spray available at KMart stores.

  • The citronella-scented geranium, also sold as the citronella or mosquito plant and candles, do emit a fragrance that repels mosquitoes, but the range is only a couple inches from the plant or candle.
  • Mosquito & Gnat Repellent – Repels mosquitoes, gnats and more. This dry granular formula contains lemon grass, mint and garlic oils to make a non-poisonous, non-toxic and biodegradable flying insect repellent. No mixing or water outlet needed, simply apply granules to area. Safe for humans, pets and plants. Lasts up to three weeks and does not degrade in rain. 1 lb. covers 800 square feet. USA made. NOTE: This item can not be shipped to California.
  • Lentek Portable Mosquito Contro Repel Mosquitoes away without messy creams or dangerous chemicals! The Mosquito Contro has two selected frequencies to keep the biting female mosquito away. Male mosquitoes donÂŽt bite humans. The primary technology replicates the wing speed noise of a male mosquito- which the female mosquito instinctively avoids. The second frequency replicates the noise of a dragonfly, the natural predator of biting mosquitoes. Perfect for indoors or picnics and other outdoor activities. Covers a 256 sq. ft. area. $19.99

Outdoor Adult Mosquito Killers

What attracts biting insects to people? There are an estimated 400 chemicals emitted from human skin and about 100 volatile compounds in each human breath that mosquitoes can detect. The combination and amount of chemicals given off is believed to be why some people are more readily bitten than others. Carbon dioxide, water vapor, and heat that result from breathing are believed to be a major factor. Mosquitoes also need cholesterol and B vitamins and this may affect their choice of hosts for their blood meals.

Bug zappers and devices which electrocute flying insects are ineffective in managing mosquitoes. Researchers testing these devices found few mosquitoes among the insects killed by them. Ultrasonic devices and incense are also ineffective. Bats and birds do eat mosquitoes, but can’t be considered an effective form of control.

The first 2 devices below use carbon dioxide, generated inexpensively from a propane or butane tank (those used with barbecues), to attract adult mosquitoes and then trap and kill them. When a person exhales, their carbon dioxide and other odors mix to produce a plume which mosquitoes follow. These devices mimic the breathing of humans and mammals.

  • The Mosquito Magnet(r) mimics a large mammal by emitting a plume of carbon dioxide, heat and moisture, which when combined with an additional attractant, octenol, is irresistible to female mosquitoes (the ones that bite), no-see-ums, biting midges, black flies, and sandflies. It attracts biting insects, while simultaneously vacuuming the insects into a net where they dehydrate and die. It is best placed between the area that needs protection (patio, pool, porch, restaurant, etc.) and the insect source, i.e. woods, swamp, mangroves etc. Covers up to an acre. There are various models starting at starting around $495.Some online sources for Mosquito Magnet are Mosquito Magnet Depot and Frontgate.
  • The Lentek Mosquito Killer Trap utilizes the documented attractiveness of C02, moisture, body temperature (thermal imaging), color, and airflow to attract, capture and kill mosquitoes. Mosquitoes are virtually eliminated in an area up to 3/4 of an acre. Beneficial insects remain unharmed since mosquitoes are specifically targeted. $299 – $379Some online sources for the Lentek Mosquito Trap are Lentek and Compact Appliances.
  • MosquitOFF(r) Mosquito and Flying Insect Killer contains Permethrin, a long-lasting insecticide that provides contact and residual control for up to 4 weeks of many hard-to-kill sucking and chewing insects. Kills mosquitoes, ants, earwigs, crickets and many other insects. Apply when insects appear. Wet plants thoroughly to dripping point and penetrate dense foliage.

Preventing Entry Into the House

There are a number of things which can be done to prevent mosquitoes from entering the house.

  • Make sure that doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes.
  • Keep doors and windows closed, especially at dawn, dusk, and early evening.
  • Repair any leaking plumbing and outside faucets.
  • Lentek Portable Mosquito Contro described above can also be used indoors.
  • Use outdoor repellents and larvicides around the perimeter of the house.
  • Eliminate all sources of standing water near the home (see above).

Personal and Bird Protection Measures

  • Stay indoors at dawn, dusk, and early evening.
  • Wear long-sleeved shirts, long pants and socks outdoors. For some reason, black and white fabrics particularly seem to attract the bugs, so try earth tones.
  • Mosquitoes will bite through thin clothing, so wear thicker materials.
  • Do not take pet birds outside, especially at the times when mosquitoes are active or cover cage with a protective netting.
  • If birds are housed in outdoor aviaries, add screening if possible.
  • Use insect repellent on exposed skin, following the manufacturer’s directions. Spray clothing with repellents containing permethrin, DEET or neem oil.

Personal Repellents

Mosquito repellents containing DEET are considered the most effective on the market, but studies on rats indicate that prolonged use may result in damage or death of brain cells. So repellents containing DEET should not be used for extended periods or on children whose tender skin quickly absorbs the product.

Neem Products repel and affect the development of mosquitoes. In a study, two percent neem oil mixed in coconut oil, when applied to exposed body parts of human volunteers, provided complete protection for 12 hrs. from bites of all anophelines. Kerosene lamps containing 0.01-1% neem oil, lighted in rooms containing human volunteers, reduced mosquito biting activity as well as the mosquitoes resting on walls in the rooms; protection was greater against Anopheles than against Culex. Effectiveness of mats with neem oil against mosquitoes has also been demonstrated; the vaporizing repelled mosquitoes for 5-7 hrs at almost negligible cost.

Permethrin, citronella, cedar oil and geraniol have also been used to repel mosquitoes.

Andrew Weil, MD’s website, with information and products for optimum health and wellness, offers some information on repellents. He mentions garlic solutions and Skin-So-Soft, made by Avon, a moisturizing lotion that mosquitoes hate. Also mixtures of essential oils such as pennyroyal oil and eucalyptus which he believes are moderately effective. Where mosquitoes are abundant, he suggests neem oil, which in one study provided significant protection for up to 12 hours. He also mentions another study in which lemongrass and citronella oils each provided almost complete protection against most mosquitoes.

  • There are many products containing DEET available in local stores. Effective repellents contain 35% DEET (N,N-diethyl-meta-toluamide). Higher concentrations give no added protection. (The NYC Department of Health suggests – Use 10% or less DEET for children and no more than 30% DEET for adults, do not use DEET on infants.)
  • There are several natural bug repellents, such as Bite Blocker by Surefire, that are both safe and effective. But they need to be reapplied frequently.
  • DEET-Free Botanical Outdoor Gel This product is based on neem oil and contains no DEET. Neem has been used to repel insects for thousands of years. This gel is made with a neem leaf extract and aloe vera base (to soothe bites you already have!), neem oil, citronella and geraniol. Apply liberally every 4 hours.
  • EquuSkreen is an all natural insect repellent containing citronella, cedar oil, rosemary oil, and olive oil. It repels biting insects including gnats, yellow flies, black flies, horse flies, deer flies, mosquitoes, ticks, and fleas and is effective and safe for use around small children, the elderly and on large and small animals. It has been tested and approved by Purina Mills and throughout out the U.S.A. EquuSkreen has proved to be highly effective in repelling flying insects from horses and other animals around stables.
  • SkinSkreen is an all natural insect repellent safe for use on children and the elderly. It repels biting insects including mosquitoes, yellow flies, black flies, no seeums, gnats, chiggers, ticks, and deer flies. Active Ingredients are 1.12% Citronella, 1.18% Peppermint Oil, 0.75% Lemongrass Oil, 0.37% Cedar Oil and 0.08% Rosemary Oil.