Catangui, Michael A.

Wilson, James A.

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeFact Sheets SDSU Extension6-1-2004Controlling Mosquitoes Around the Home andYardJames A. WilsonSouth Dakota State UniversityMichael A. CatanguiFollow this and additional works at: http://openprairie.sdstate.edu/extension_factThis Other is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in Fact Sheets by an authorized administrator of Open PRAIRIE: OpenPublic Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu.Recommended CitationWilson, James A. and Catangui, Michael A., "Controlling Mosquitoes Around the Home and Yard" (2004). Fact Sheets . Paper 103.http://openprairie.sdstate.edu/extension_fact/103have always been a nuisance in South Dakota, but withthe recent spread of West Nile virus, they have alsobecome an important public health concern in bothcountryside and city. Although the West Nile virusmainly infects birds, it can be transmitted to humans andother animals by certain species of mosquitoes that takeblood meals from both birds and humans. The bite fromjust one infected mosquito is all that is needed to transfer the disease.In humans, West Nile virus disease symptoms vary fromno visible effect to flu-like symptoms, paralysis, ordeath. All age groups are susceptible, but the elderly andthose with weakened immune systems are more likely toexperience severe forms of the disease.Public mosquito control programs have been started inmany cities and towns in the state, but they are notavailable in rural areas. Even the best mosquito controlprogram will only reduce the risk from West Nile virus.Wherever you live, personal protection against mosquitobites is your best approach.MOSQUITOESFS 923James A. WilsonExtension pesticide coordinatorandMichael A. CatanguiExtension entomologist CONTROLLINGMOSQUITOESSOUTH DAKOTA STATE UNIVERSITYCollege of Agriculture and Biological SciencesCooperative Extension ServiceAround the Home and YardFig 1. Mosquito larvae (wrigglers) and pupa (tumbler,on back page). These juvenile mosquitoes developwhile suspended from the water surface. Larvae andpupae are aquatic immature forms of mosquitoes.       •  Use personal insect repellents and avoid times of peak mosquitoactivity. These are the most effective steps in reducing risk. •  Eliminate standing water, where possible, to reduce mosquitonumbers. Consider treating stagnant water that cannot be drainedwith an approved larvicide. •  Finally, in special instances, consider chemical control of adultmosquitoes. Using chemicals around the home and yard is theleast effective and shortest-lasting protection, but when outdooractivities are planned, this approach can be used in combinationwith the previous methods.AVOID BEING BITTENFemale mosquitoes must have a blood meal in order to reproduce.Male mosquitoes feed on plant nectar and do not bite humans. Mosquitoes spend most of the day in shaded resting areas. Expectto find them in tall grass, near the north walls of buildings, andunder decks. At dusk, and again at dawn, hungry females come outand search for the warmth, carbon dioxide, and other scents thatwarm-blooded animals give off. If possible, avoid outdoor activityduring those times. If you will be outside at these times, however, wear loose-fittingclothing that covers as much skin as possible and apply mosquitorepellents. Personal mosquito repellents containing the active ingredientDEET are the recommended products for application to the skin.Botanical products are available that have some repellency, butthey provide protection for a shorter length of time than productscontaining DEET. Protectants containing permethrin that areapplied only to clothing can be used in combination with DEETor botanical repellents. (Refer to Extension Service FS 920, Personal Mosquito Repellents,and EXEX 8147, Personal Mosquito Repellents Available in SouthDakota, for more details.)You also need to reduce the chances of mosquitoes getting insideyour home. Check windows to ensure that screens are in place andare in good repair. Check the seals around doors. Consider replacing outdoor lighting near entrances with “bug lights.”  Theselights give off a wavelength of light that is not as attractive toinsects as conventional lighting.REDUCE BREEDING AREASMosquitoes must have water to reproduce. Under ideal conditionsthey can go from egg to adult in less than 10 days. Just an inch ofwater in the bottom of a forgotten tin can can be a hatching site forhundreds of mosquitoes. Drain or dump and refresh water every week or so. Considerchecking the following locations:Fig 2. Mosquito egg raft about to hatch into wrigglers.bird bathsboats/pickup boxesbucketscans/jars/junkculvertsleaky outside faucetspet dishesplugged rain gutterspots/planterstoystireswading poolswagonswheelbarrows        Larval mosquito controlNon-chemical larval controlIf water sources cannot be drained or refreshed, consider coveringsmall containers. Aerating the water or stocking insect-eating fishin backyard ornamental pools or nearby ponds may help. In SouthDakota, the recommended fish is the fathead minnow, commonlyavailable as a bait fish. Removing weeds in and around the pond also may help cut mos-quito numbers in some locations. Clearing out the vegetation opensup the water to wave action by wind. Water that is agitated bywaves will reduce mosquito larval survival; they will drown sincethey breathe air by attaching themselves to the water’s surface. Some larval control products are available that produce a thin filmover the water surface. These films either prevent the larvae frombreathing or reduce the surface tension of the water, causing themto drown. Larval control pesticides(Note: for a complete list of all pesticides registered for mosquitocontrol in South Dakota, refer to Extension Extra EXEX 8148.)The most common products available to homeowners for control-ling mosquito larvae contain proteins derived from Bacillusthuringiensis subsp israelensis or Bti. These products are commonly sold as granules or pre-formed blocks (Fig 4) thatrelease the Bti protein when placed in water. The Bti protein istoxic only to mosquito wrigglers and the larvae of certain aquaticflies such as midges and black flies. It has no harmful effects onhumans, horses, fish, tadpoles, frogs, crustaceans, snails, or othernon-target aquatic animals. Formulations of Bti are available that last from as little as 3 days toas long as 30 days. Products containing Bti are an excellent choicefor stagnant water areas that cannot be drained.Larval products containing methoprene are also available. Theseproducts act as insect growth regulators and prevent the pupae ortumblers from maturing into adult mosquitoes. Both methopreneand Bti products become less effective as mosquito larvae mature.The products are ineffective against adult mosquitoes.Adult mosquito controlNon-chemical adult mosquito controlCarbon dioxide-baited trapsFemale mosquitoes looking for a blood meal are attracted to carbondioxide gas that is exhaled or emitted by their potential human oranimal hosts. Because of this biological fact, carbon dioxide-baited traps havebeen used by public health workers in monitoring mosquitoes (Fig5). Numbers and species of mosquitoes caught in such traps areusually compared with historical data and used as a guide or thresh-old to signal various control operations. Recently, some companieshave commercialized carbon dioxide-baited mosquito traps andhave made some models available to the general public (Fig 6).Carbon dioxide-baited traps available for use by homeowners inSouth Dakota use propane gas as the source of carbon dioxide. Thecarbon dioxide gas is discharged from the tank as a continuousFig 4. Wrigglers feeding on a Bti pre-formed block.                             stream or in bursts or plumes that mimic the exhalations of a farmanimal. Some traps supplement the already attractive carbon dioxide with achemical called octenol. Octenol mimics gases that are naturallyfound in the stomach of cattle. A suction fan then draws the attracted mosquitoes into a containerwhere they die of desiccation. Carbon dioxide-baited traps can be powered by propane alone or byboth propane and electricity. The maximum effective range of eachtrap varies from one-half to one acre. Traps that run on propanealone and that can cover an acre are typically the most expensive.Mosquito data collected from Grand Forks, N.D., in 2002 indicatedthat a certain model of a carbon dioxide-baited trap synergized withoctenol (Mosquito Magnet “Liberty”) caught up to 8,000 femalemosquitoes per night during peak mosquito season in early July.The number of mosquitoes captured using this particular carbondioxide-baited trap was about 15 times greater than the number ofmosquitoes captured with a standard New Jersey light trap. TheNew Jersey light trap was not baited but was equipped with a small25-watt clear light bulb and suction fan to attract and collect mosquitoes.*  Although certain carbon dioxide-baited traps can dispatch thousands of mosquitoes per night and despite good reviews fromowners, it must be remembered that there will always be certainmosquito species that will not come to even the best mosquito traps.Mosquito traps will usually identify on their labels which speciesare not attracted to the trap. Since all it may take is just a single bite from a single infected mosquito to cause illness, personal repellents and other means ofcontrolling mosquito wrigglers and adults should still be used byhomeowners who may also own carbon dioxide-baited traps.Bug lights At night, mosquitoes and many other nocturnal insects are attractedto light given off by “white” light from ordinary bulbs. In contrast,yellow light emitted by “bug light” bulbs is about a third less attractive to nocturnal insects. Although “yellow” light is not completely unattractive to insects,the reduction in mosquitoes and other insects can be substantial. We therefore recommend that lighting fixtures around the home andyard be equipped with bug lights rather than with ordinary whitelight bulbs. Bug lights are available either in incandescent or fluorescent forms (Fig 7).Fig 5. Surveillance trap commonly used in public mosquito control programs.Fig 6. A homeowner carbon dioxide-baited mosquito trap.Fig 7. Fluorescent and incandescent bug lights.           Adult mosquito control pesticidesAdult mosquito control is not the most effective way to reducemosquito numbers. Removing standing water and controlling larvae should still be the primary means of mosquito controlaround the yard and home. However, there are occasions when pesticides to control adult mosquitoes may become necessary, especially when mosquitonumbers need to be reduced quickly. Adult public mosquito controlprograms often employ ultra low volume (ULV) applications fromspecialized equipment that dispenses concentrated pesticides in anaerosol fog. This is impractical for homeowners. However, portable thermal foggers that use either propane or electricity to convert an insecticide (resmethrin) into a thermal or“hot” fog are available to homeowners for use around the yard andhome. Thermal foggers only kill mosquitoes that come in contactwith the insecticidal fog, which usually dissipates within hoursafter fogging.Another treatment is barrier or residual treatments of mosquito rest-ing areas for short-term reduction of mosquito numbers, especiallyif you are planning outdoor grilling or a backyard family gathering. A home barrier treatment generally is an application of a labeledinsecticide onto mosquito resting areas around the yard and homewith an ordinary household sprayer, hose-end sprayer, or ready-to-use container equipped with a spray gun. The most common insecticides for home use contain the active ingredients bifenthrin,cyfluthrin, deltamethrin, lamda-cyhalothrin, or permethrin. (Referto Extension Extra, EXEX 8148). Apply the insecticide to surfaces where mosquitoes will be restingduring the day—the north or sheltered sides of board fences, wallsiding, eaves, and outbuildings; trees and shrubs; under decks; andin tall grass or weeds. Apply in advance of the planned activity sothat the treated surfaces are completely dry before use. Sprayobjects and structures; just wetting the lawn with insecticide is not effective.Depending on the insecticide and the weather, outdoor barrier orresidual treatments may keep on killing mosquitoes on contact forup to 3 weeks. While this may help reduce the mosquitoes in thetreated area, mosquitoes from surrounding areas may still fly in tothe treated yard seeking a blood meal.Follow these precautions:•  Before using any pesticide, especially around the home, READAND FOLLOW ALL LABEL DIRECTIONS. •  Do not allow people or pets into the treated area until the restricted entry time has passed. •  Avoid treating locations that are listed as prohibited on the label. •  Be particularly careful not to make applications to areas that maycome into contact with food. •  Purchase and use protective clothing such as chemical-resistantgloves. •  Remove and wash clothing used during the application, andshower, using plenty of soap. •  Clean application equipment and store pesticide in its originalcontainer, well out of reach of children. You probably have heard claims for products such as bug zappers,high frequency electronic repellents, Brewers yeast, and citronella.The effectiveness of these products against mosquitoes has notbeen demonstrated.    WRAP-UPMosquitoes have always made our outdoor and recreational activi-ties uncomfortable. Now we know that mosquitoes also are capableof transmitting microorganisms that may cause diseases in humans. In 2003, for example, a mosquito-borne virus called the West Nilevirus caused illness in over a thousand South Dakotans and caused14 deaths. Over 170 individuals with severe forms of the diseaserequired long periods of time to recover and some have not fullyrecovered.South Dakota has 44 known species of mosquitoes. The westernencephalitis mosquito Culex tarsalis (Fig 8) is perhaps the mainvector of West Nile virus and is present in all South Dakota Fig 8. Culex tarsalis. The female can hibernate in the northern U.S., and larvae areproduced from early spring until late fall. Characteristic markings are the broadwhite band on the proboscis (flexible feeding tube) and white bands on the tarsi(outer parts of the legs).counties. Seven other mosquito species have tested positive for thevirus, including the most common mosquito in the state—the inlandfloodwater mosquito, Aedes vexans. The importance of mosquitoes as a nuisance and as potential vectors of disease-causing microorganisms in South Dakota cannotbe overemphasized. Homeowners—city and country—can play amajor role in rural and community mosquito control efforts.•  They can reduce the number of potential mosquito breeding siteson their properties, most efficiently by eliminating unnecessarystanding water. •  They can treat remaining breeding sites with various larvicides toprevent mosquito wrigglers from becoming adult mosquitoes. •  If adult mosquitoes successfully emerge from breeding sites,homeowners can treat their resting areas with barrier or residualsprays and/or thermal fog.•  Homeowners can use yellow bug lights to repel adult mosquitoesor divert the insects to carbon dioxide-baited traps before theinsects have the chance to bite humans.Some mosquitoes will always “get through.” We therefore stronglyrecommend that South Dakotans who will be outdoors wear a mosquito repellent of their choice, avoid being outdoors aroundsunset and sunrise, and cover as much skin as possible with appropriate clothing. South Dakota outdoors is a great place in the summertime. Bylearning basic mosquito biology and taking simple precautions,we can still safely enjoy it. For more information:FS 920, Personal Mosquito Repellents:http://agbiopubs.sdstate.edu/articles/FS920.pdfEXEX 8147, Personal Mosquito Repellents Available in South Dakota:http://agbiopubs.sdstate.edu/articles/EXEX8147.pdfEXEX 8148, Pesticides Registered for Mosquito Control in South Dakota:http://agbiopubs.sdstate.edu/articles/EXEX8148.pdfThe use of trade names is for the convenience of readers only and does not consti-tute an endorsement of these products by the U.S. Department of Agriculture, SouthDakota State University, or the South Dakota Cooperative Extension Service.Consult the product label before using. Information provided in this fact sheet is foreducational purposes only.* This data was provided by Dr. Jeff Vaughan, Assistant Professor of Biology,University of North Dakota, Grand Forks. Dr. Vaughan is currently conducting stud-ies on the field performances of carbon dioxide-baited traps in North Dakota.This publication may be accessed through the web at: http://agbiopubs.sdstate.edu/articles/FS923.pdfIssued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with theUSDA.  Gerald Warmann, director of CES, associate dean, College of Agriculture & Biological Sciences, SouthDakota State University, Brookings.  South Dakota State University is an Affirmative Action/Equal OpportunityEmployer and offers all benefits, services, education, and employment without regard for race, color, creed,religion, national origin, ancestry, citizenship, age, gender, sexual orientation, disability, or Vietnam Era veteranstatus. FS923: 50,000 printed at $_.__ each.  June 2004. 

Controlling Mosquitoes Around the Home and Yard

https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1102&amp;context=extension_fact

Controlling Mosquitoes Around the Home and Yard

Abstract

Similar works

Full text

Available Versions

Public Research Access Institutional Repository and Information Exchange