Mosquito Control Around the Home (en español)

Lifecycle of the Mosquito

Mosquito Lifecycle

There are over 40 species of mosquitos in Morris County. Mosquitos require standing water to breed.

  • Egg: Eggs are laid on the water surface or where flooding will occur.
  • Larva: The mosquito begins to develop.
  • Pupa: Wings, legs and appendages develop.
  • Adult: The female adult has a blood meal, then returns to the water to start the cycle again.

Our mosquito biology flyer has more information.

Mosquito Reminders

  • Mosquitoes breed only in water.
  • Mosquitoes must have water for at least 7 days to complete their development.
  • Any standing water may breed mosquitoes.
  • Control measures should be directed at their breeding places.

What Homeowners Can Do

  1. Dump all standing water from containers including kiddie pools, flower pots, garbage cans and tarps.
  2. Clean out bird baths once a week.
  3. Eliminate standing water and low areas on your property.
  4. Clean the gutters on your house.
  5. Use screens to prevent mosquitoes from entering the home.
  6. Keep ditches and stormwater facilities free of debris.
  7. Use fountains or fish in ornamental ponds.

Call your local mosquito control agency for more information.

More Information


Products

We act first to control the immature (larval) stages of mosquitoes, using the lowest impact products that are suitable for the task.

What is BTI?

Bti (Vectobac, Aquabac or Bactimos, trade names), or Bacillus thuringiensis israelensis, is a naturally occurring bacteria which produces a crystal that is fatal to mosquitoes when eaten. Bti has little or no impact on other organisms in the mosquito environment.

This organism was first isolated in 1977 from dead mosquito larvae in Israel. Although similar to a strain that has been used for caterpillar control since the early 1900’s, the new variety was found to be very effective and very specific against mosquitoes. Bti is grown commercially in fermentation tanks, but only a dormant spore, not live bacteria, are used in the finished product.

All mosquitoes start their lives in water, with the young hatching from eggs into what is known as the larval, or wriggler, stage. They move through the water, filtering out food as they go. When Bti is placed in this environment, mosquitoes eat it. The Bti spores, which contain a crystallized toxin, are released by the mosquito’s stomach fluids. The toxin ruptures the stomach of the mosquito, causing death. Other organisms are not affected in this manner. Polluted water will bind the material and require higher application rates. Bti takes longer to act in cold water due to the slower feeding rate of larvae at low temperatures, but is eventually effective in these conditions. The product does not work against older larvae or the next stage in the mosquito life cycle (pupa or tumbler) because mosquitoes stop feeding before becoming adults.

Bti is formulated as a granule or as a dilute liquid. The granules are applied without further mixing at about 5-10 lbs. per acre, the liquid is diluted so that 1/2 to 1 pint per acre is applied. This product carries only a caution label, the lowest toxicity category of EPA classifications. Bti can be considered essentially non-toxic for humans. After application, the product breaks down within one or two days.

Reports from field staff who use Bti indicate that only mosquitoes are gone after an application is made- the habitats are still teeming with other aquatic life. This enable us to “surgically” remove only the organism that we want to- the mosquito.

Contact us if you have questions about Bti or any other mosquito control related products or practices.

What is Altosid (Methoprene)?

Altosid, or methoprene, is a compound that was developed after scientists discovered and analyzed a hormone in mosquitoes that kept them in the juvenile, or immature stage. Other, similar compounds produce the same effect in other insects.

Mosquitoes, after hatching from the egg stage, go through four larval (immature) stages, then become pupae (tumblers) before becoming adults. During the immature stages, a juvenile hormone is present that stops them from becoming adults. By placing a chemical mimic of this compound in the water in very small quantities (around 0.010 lb./acre of active ingredient – less than an ounce/acre), mosquitoes are prevented from maturing to adulthood. They simply die during the pupal stage. A benefit of using Altosid is that larvae remain in the food chain, reducing the impact on other organisms in the habitat. Altosid must be present when the mosquito is in the later stages of larval development to work.

Altosid is formulated as a liquid, a 30 day slow release pellet, a 30 day briquet and a 90 day briquet. The benefit of the slow release versions is that they can be placed in difficult to reach locations and continue controlling mosquitoes for a long time. Altosid carries a caution label, the lowest toxicity category of EPA classifications. The product can be considered non-toxic for humans. Altosid is one of the so called “biorational” compounds, meaning the impact on the environment is minimized by using natural products or chemicals that are similar to these natural products. Although these compounds are generally somewhat expensive, we believe they are worthwhile because they work to control mosquitoes without harming other organisms.

Contact us if you have questions about Altosid or any other mosquito control related products or practices.

What is Abate?

Abate is a low toxicity insecticide that is applied to waters found to have young mosquitoes (larvae or wrigglers) present. Abate is very effective against mosquitoes throughout this aquatic stage, but when applied as indicated on the label, has little impact on other life forms that are present.

This product is a chemical in the organophosphate group. Once applied, Abate will break down rapidly and will not build up in the environment. Abate can be applied as a granular material (2% or 5%) at the rate of 2-5 lb. per acre, or as a liquid at the rate of about one ounce of active ingredient per acre. Applications can be made with hand equipment, power sprayer or helicopter. Heavy pollution or very cold water will substantially decrease the effectiveness of the product. Abate does not kill the pupa , or tumbler stage of mosquitoes. Generally, the Division of Mosquito Control uses Bti for young mosquito larvae and Abate for the older larvae that no longer feed (making Bti ineffective).

Numerous studies have shown that Abate has very low toxicity for mammals, with little or no capability for drastic harm. In addition, there is no evidence that Abate causes an increased risk for cancer. Even so, the product is an insecticide and is therefore used only by trained applicators when mosquito larvae are found. There is also a high margin of safety for other organisms in the mosquito environment.

Contact us if you have questions about Abate or any other mosquito control related products or practices.

What is Golden Bear or Bonide Oil?

There are two light oils used for mosquito control, Golden Bear and Bonide. Both of these products have similar qualities. They are light mineral oils that have minimal impact on plants and animals in the mosquito environment.

Modern mosquito larviciding oils are much “tamer” than the old fuel oil mixtures that were once used for mosquito control. They are a very light weight, and contain spreading agents so that only a small amount is required to achieve mosquito control. In most situations, these oils are put out at the rate of 2-3 gals. per acre. Applications are almost always made with hand held sprayers. Because oils kill mosquitoes by suffocation, they are suitable for all stages of mosquitoes. These are the only products that will kill the pupa (or tumbler) stage. Due to expense and the slightly greater impact on the environment than our other mosquito control products, oils are used mostly when pupae are present, or when a broad range of mosquito development is seen. Presence of much vegetation will decrease the effectiveness of oils, although cold temperatures do not have a negative impact on their performance.

These oils will not harm most plants and animals in the mosquito environment when the product is properly applied by trained applicators. They break down within a few hours to a few days after being applied, depending on the air temperature and level of sunlight exposure.

Contact us if you have questions about Golden Bear or Bonide oils or any other mosquito control related products or practices.

What are Mosquitofish?

Mosquitofish (scientific name, Gambusia affinis) are a biological control that help us reduce mosquito numbers and the need for applying mosquito control products. The Division of Mosquito Control has a number of ponds where these fish survive the winter, and in the spring we stock appropriate permanent water habitats with them to provide long term mosquito control.

The fish are small (maximum size around 2.5 inches), aggressive top feeding minnows that consume huge numbers of the aquatic stage of the mosquito (the larva and pupa). They are originally a tropical fish, but survive quite well in our stocking ponds in northern New Jersey.

Where can these fish be used? Only in isolated, permanent water sites. They cannot survive drying down, and because they are not a native species must be applied only to areas where they are unlikely to affect other fish and aquatic organisms. Just as with insecticides, they are not right for every environment and are placed only after a staff member makes an assessment of the habitat suitability. Not all permanent water sites produce mosquitoes, or are appropriate for these fish. We follow the guidelines of the State Mosquito Control Program in making such determinations.

Contact us if you have questions regarding potential sites where mosquitofish may be used or any other mosquito control related products or practices.

What is Malathion (Fyfanon)?

Malathion is a low toxicity, non-residual insecticide that is used in very small amounts to control adult mosquitoes. This product is not residual (does not last long) and is applied with specialized equipment in a manner that maximizes mosquito control but minimizes the impact on other organisms.

Malathion is an organophosphate chemical with very little toxicity for mammals. For mosquito control operations, we apply the product at 1/2 ounce per acre. A group of people, each weighing 187 lb., would have to drink over 4 ounces of malathion for half of them to be fatally poisoned. In addition, numerous studies have shown that malathion does not lead to an increased risk of cancer or birth defects. Malathion kills by disrupting the nervous system. In mammals, the product is quickly broken down into non-toxic components. In insects, the product is broken down, slowly, into another compound that is fatal to insects.

Application of malathion is made with Ultra Low Volume (ULV) equipment that puts out very fine droplets (5- 20 microns in size: there are 25,400 microns in an inch) of concentrated material at very low levels (1/2 to a maximum of 1 ounce per acre). In Morris County, we have found the lowest rate to be effective. Malathion is broken down rapidly after application, and must contact flying mosquitoes directly to kill them. Malathion is toxic to other insects, so care must be taken to avoid contact with beneficial insects such as honeybees.

Spraying for adult mosquitoes is a last resort. Most mosquito control work goes on “behind the scenes”, using water management, fish, and products to control immature mosquitoes in the water where they begin their life cycle. Controlling adult mosquitoes is more difficult because they are spread out and moving.

Contact us if you have questions about malathion or any other mosquito control related products or practices.

What is Scourge (Resmethrin)?

Scourge is a low toxicity, non-residual insecticide that is used in very small amounts to control adult mosquitoes. This product is not residual (does not last long) and is applied with specialized equipment in a manner that maximizes mosquito control but minimizes the impact on other organisms.

Scourge is a synthetic pyrethroid with very low toxicity for mammals. This is a mimic of pyrethrum, a natural insecticide produced by certain chrysanthemums. The product is mixed with an agent that makes it more effective, called a synergist (piperonyl butoxide). Scourge is applied at the rate of 0.5 to 3.0 ounces per acre, so that only 0.02 to 0.12 ounces of insecticide are actually applied per acre. A group of people each weighing 187 pounds would have to drink over 12 ounces of Scourge for half of them to be poisoned. Scourge does not impact non-target organisms when applied at the recommended rates. Even very sensitive honeybees are not harmed by Scourge when applied at 10 times the maximum label rate.

Applications of Scourge are made with Ultra Low Volume (ULV) equipment that puts out very fine droplets (5-20 microns in size: there are 25,400 microns in an inch) of material at very low levels ( 0.5 to 3.0 ounces of finished product per acre, of which 4% is resmethrin and 12% is piperonyl butoxide). In most cases, the lowest rate is used. Scourge breaks down rapidly in sunlight, so there is no build up of this material in the environment.

Spraying for adult mosquitoes is a last resort. Most mosquito control work goes on “behind the scenes”, using water management, fish, and products to control immature mosquitoes in the water where they begin their life cycle. Controlling adult mosquitoes is more difficult because they are spread out and moving.

Contact us if you have questions about Scourge or any other mosquito control related products or practices.