Mosquitoes and Mosquito-Borne Diseases
•WestNileVirus
•MosquitoesofConcern
•EnvironmentalMosquitoControl
•RepellentUseandSelection
•CanineHeartwormandTreeholeMosquitoes
•InsectsthatResembleMosquitoes
Protecting the Public from Vector-Borne Disease since 1989
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
2 www.sgvmosquito.org
Mosquitoes & DiseAseMosquitoescanbeannoying,buttheyaremostimportantasvectors(transmitters)ofdisease.Nearly70%ofemergingthreatstopublichealthworldwidearediseasesofanimalstransmittedtohumans.DiseasesoncenearlyeradicatedaremakingacomebackintheUnitedStatesandaroundtheworld.
VirusesthatcauseWestNile(WNV)andotherencephalitidesarenormallyfoundinbirds,butalsocauseillnessinpeopleeachyear.Sinceintroducedin2003,morethan600peoplehavebeensickenedbyWNVinLosAngelesCountyalone.Thankfully,mostpeoplebittenbyaninfectedmosquitowillnothavesymptoms.Approximately20%willdevelopWestNilefever.Symptomsmayincludeheadache,fever,bodyaches,vomiting,nausea,swollenlymphglandsandskinrashonthechest,stomachandback.Rarely,thisviruswillinvadethebrainand/ornervoussystemleadingtoamoresevereformofillnesstypifiedbymentalconfusion,coma,paralysis,andinextremecases,death.
ThereisnocureforWNV,butbyfollowingsimplemosquito-proofingandbitepreventiontipsfoundinthisbrochure,youcanreduceyourriskandprotectyourfamilyfrommosquito-transmitteddisease.
Mosquitoes can transmit a variety of viruses and parasites to people and animals including West Nile, St. Louis encephalitis, and western equine encephalomyelitis viruses, canine heartworm, and malaria.
Out for Blood
Mosquitoesaresmallbitingflies.
Bothmaleandfemalemosquitoesfeedonplantjuicesforfood.
Onlyfemalesbitetogetbloodfrommammals,birds,amphibians,andreptilesusingspecializedmouthparts(proboscis).
Proteinsinbloodareneededtoproduceeggs.
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
egg
Adultfemalemosquitoeslayapproximately100-250eggseitherinclusterscalledraftswhichfloatonthesurfaceofthewater,orsinglyonoratthewater’sedge.Larvaehatchfromeggswithindaysaftercontactwithwater.
LArvA
Larvaeareoftenfoundatthesurfaceofthewaterwheretheybreatheandfeed.Theyliveinawidevarietyofwater-filledsourcesincludingneglectedswimmingpools,ditches,stormdrains,householdcontainers,treeholes,ponds,horsetroughs,anddiscardedtires.Larvaefeedonalgaeandbacteriainthewaterandshedtheirskinfourtimesastheygrowoverseveraldaysorweeks.
PuPA
Aspupae,mosquitoestransformintheircocoon-likeshell.Pupaedonotfeedbutmustcometothewater’ssurfacetoobtainoxygen.Oncefullydeveloped,thepupalskinsplitsandtheadultmosquitoemerges.
ADuLt
Newlyemergedadultmosquitoesrestonthesurfaceofthewateruntiltheyarestrongenoughtofly.Aftermating,femalemosquitoesflyoffinsearchofabloodmealnecessaryfordevelopingeggs.
Femalemosquitoesareattractedtoheat,odors,andcarbondioxidegivenoffbyhostssuchashumans,mammals,reptiles,andbirds.Adultmosquitoesliveanaverageof1-3weeks.
Life Cycle of the MosquitoTheentirelifecyclefromeggtoadulttakesanaverageoffivetoseven(5-7)daysformostspecies.
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
4 www.sgvmosquito.org
species of ConcernThereareapproximately3,500speciesofmosquitoesworldwide.Californiaishometo53differentspecies,15ofwhicharefoundinLosAngelesCounty.Thoseofgreatestconcernfallintooneoffourgroupslistedbelow.
Culex
ThemostprevalentmosquitoesinurbansouthernCalifornia,Culexthriveinnaturalandman-madesourcesofhighlyorganicwaterincludingdrainages,undergroundsumps,dirtyswimmingpools,andcontainers.Mostcanmaturefromeggtobitingadultin5-7days.
Somespeciesflyonlyshortdistances,butothersmayflyupto10milesinsearchofabloodmealandareactivefromdusktodawn.
Thesemosquitoesfeedprimarilyonbirds,butalsobitehumansandaremajorvectorsofWestNile,St.LouisencephalitisandWesternequineencephalomyelitisviruses.
AnOPheles
ThemostcommonAnophelesinsouthernCaliforniatransmittedmalariaamongearlysettlers.WhilemalariaisnolongerendemicinCalifornia,localoutbreakscanoccurwheninfectedtravelersarefeduponbylocalmosquitoes.
Anopheleslarvaeareoftenfoundinriversandcanyonstreamsinalgaematsandcattailstands.
Femalesarestrongfliersandaggressivebitersatdawnanddusk.Anophelesmosquitoesprefertofeedonhumansandlargemammals.
Culex are often brown or reddish and feed oriented horizontally
Anopheles feed head down at a characteristic 45-degree angle.
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
AeDes
ManyAedesinhabitcoastalmarshesandirrigatedpasturesorbreedincontainersandtreeholes.Aedesfeedaggressivelyduringthedayandaresignificantvectorsofdengueandothervirusesworldwide.InCalifornia,thetreeholemosquitoisresponsiblefortransmittingcanineheartwormandisoftenfoundinwoodedareaswheretreeholecavitiesarecommon.SeveralspeciesofAedeshavebeenintroducedintoCaliforniabuthavenotbecomeestablished.Ifyounoticeday-bitingmosquitoes,pleasereportthempromptly.
CulisetA
These“cool-weather”mosquitoesaremostcommonbetweenfallandspring.TypicallylargerthanCulexmosquitoes,Culisetaprefertobitelargemammalsinsteadofhumans.Larvalhabitatsincludebothsunlitandshadedponds,puddles,andartificialcontainersholdingrelativelyclearwater.Thesemosquitoesmaybeimportantinthemaintenancecycleofcanineheartworm.
Many Aedes have striking black and white banding
Culiseta are larger and darker than other common species
What can i do to avoid being bitten?
ApplyarepellentthatcontainsDEET,Picaridin,IR3535®,orOilofLemonEucalyptus.Makesureyoufollowlabeldirections!
Wearprotectiveclothing,suchaslong-sleevedshirtsandpants.
Checkandrepairallscreensandscreendoorstokeepmosquitoesoutofyourhouse.
Minimizeoutdooractivitiesatdawnandduskwhenmosquitoesaremostactive.
Actual size
Mosquitoesaregenerallyabout1/2”atfulladultsize.
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Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
6 www.sgvmosquito.org
A Bit ABout the Bite! Thatitchybumpyougetafterabiteisareactiontothesalivaamosquitoinjectswhenitfeeds.Virusesandotherpathogenscanalsobetransmittedthroughmosquitosaliva.
FinD sourCes! Lookforanythingthatcanholdwaterformorethanafewdays.Buckets,dirtyswimmingpools,tires,trashcans,andothercontainersshouldbedrainedand/orcleanedweekly.
AvoiD theM! Trytolimitoutdooractivityatduskanddawnduringpeakmosquitoseason(springthroughfall).
BLoCk ‘eM out! Makesurewindowsanddoorshavetightfitting,intactscreens.Thiswillhelpkeepotherunwantedcrittersouttoo!
use MosquitoFish! Thesesmall,hardyfishcaneathundredsofmosquitolarvaeadayinabackyardpondorothermanmadesourceofwater.
Callus,weprovidethematnochargetoourresidents.
WeAr rePeLLents! Wearlongsleevesandpantsanduserepellentswhenoutdoors.Remembertoreadthelabelsandcarefullyfollowinstructionsonallinsectrepellents.
Change WaTeR in biRdbaThs
CLean gUTTeRsRemove vegeTaTion
keep debRis fRom ReaChing CaTCh basins
RepoRT negLeCTed pooLs
dUmp sTanding
WaTeR
Fight the Bite! Don’t Breed Mosquitoes
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
Common residential Mosquito sourcesResidentialyardsareoftenthe#1sourceofmosquitoproductioninacommunity.Anythingthatcanholdahalfinchofwaterformorethanfivedayscanbeasourceofmosquitoes.Thisincludespuddlesinlawnsandgardens,flowerpotsaucers,neglectedswimmingpoolsandspas,birdbaths,cloggedraingutters,andmore.Maintain,manage,oreliminatealltypesofstandingwaterregularly.
trash bins:Keeplidsshuttightlyandremovewaterthataccumulatesinside.Drillseveraldrainholesinthebottoms.
Boats:Checkandremovewaterweeklyfromboatcovers.
Fountains and bird baths:Cleanorhoseoutweekly.
rain gutters:Keepclearofleavesandotherdebris.
Potted plant saucers:Don’toverwater.Flushoutsaucerswithahoseordrillholesinthebottomtoallowforbetterdrainage.
tires: Drillholesintireswings.Recycleusedtiresorstoreinacoveredarea.
Water bowls for pets:Rinseandfillwithfreshwater1to2timesaweek.
Water troughs:StockwithfreemosquitofishfromtheDistrict.
Leaky hoses:Replacedamagedhosesandfixleakyfaucetsandpipes.
Low areas:Donotoverwaterlawnsorgardens.
Ponds:Stockornamentalpondswithmosquitofish.Keeppondsclearandfreeofexcessvegetation.
neglected swimming pools and spas:Maintainevenwhennotinuse.Removestandingwaterontopofcovers.ReportneglectedpoolsorspasbycontactingtheDistrict.
Containers:Storecontainersupsidedown,coverorplaceinashelteredarea.
rain barrels:Covertightlywithafinemeshscreen.
Chain link fence:Coverhollowchainlinkfencepostswithcaps.
Drains:Makesurethatdrainsarenotcloggedbydebrisandflowfreely.
Flat roofs:Watermaypuddleonflatroofsduringtherainyseason.Inspectweeklyandremoveanystandingwater.
Lighting:Checkgardenlightsandeliminatewaterfromtopsoffixturesandfrominsidefloodlights.
sculptures:Checkforwaterthatmaycollectinlawnornaments.Drainorflushoutweekly.
screens:Installandmaintaintightfittingwindowanddoorscreens.
rot hole in trees:Beawarethatwatercancollectintreeholes,crotchesanddeadtreestumps.Checkwithanarboristforbestwaytomanagewaterorfillcavities.
Water under home:Useasumppumptoremovewater.
septic tanks: Screenventpipeswithafinemeshscreen.Coverexposedtanksormanholelidswithplasticorasimilarmaterialandsecureinplace.Placeseveralinchesormoreofdirtorsandoverthetopofthearea.
Wheelbarrows:Removewaterthatcollectsinsideorstoreupsidedown.
Use this home & garden checklist to help make your activities around your home safer & more enjoyable.
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
8 www.sgvmosquito.org
environmental Mosquito ControlOncemosquitoesreachadulthood,controllingtheirpopulationsbecomesdifficult.Removingsourcesofstandingwaterandtargetingimmaturemosquitoesarebyfarthemostenvironmentallysensitiveandeffectiveapproaches.
iMMAture MosquitoesEliminatingsourcesofstandingwaterremoveshabitatwheremosquitoeslaytheireggs.Immaturestagesmusthavewatertosurvive.Overturningbucketsandothercontainerswillpreventmosquitoesfrommaturingintobitingadults.Inareaswherewatercannotberemoved,mosquitoescanbemanagedusingbiologicalorchemicalcontrol.
Biological Control Mosquitofish(Gambusia affinis)aresmall,surfacefeedingfishusedthroughouttheworldtocontrolmosquitolarvae.Theyarewelladaptedtoartificialpondsandareavailablefordeliveryorpickup,freeofchargetoresidentsofourDistrict.Theyareonlyusedinartificialcontainers(backyardponds,fountains)andshouldnotbereleasedintonaturalareasorswimmingpools.
Goldfishandkoimayincidentallycontrollarvaebutarenotefficientpredatorsofmosquitoes.Pondsthatareinhabitedbypredatoryinsectssuchasdragonflies,damselflies,andaquaticbeetlesoftenhavefewermosquitoproblems.
To help mosquitofish adjust to a new home, place the container of fish directly into the pond for 10-15 minutes before release. In established ponds, extra food is not needed. If necessary, fish food or crushed dry pet food can be provided.
BioChemical/Chemical ControlThesafestandmostcommonlyusedproductsforlarvalmosquitocontrolareformulationsderivedfromnaturalsources.
Bacillus thuringiensis (Bti) and Bacillus sphaericus (Bs)arenaturalsoilbacteriathataretoxictofeedingmosquitolarvae.
Methoprene isaninsectjuvenilegrowthhormonethatpreventsmosquitoesfromsuccessfullymaturingtoadulthood.
Bothproductsselectivelycontrolmosquitoes,midges,andblackfliesandaresafetouseinpondswithfish,inhorsetroughs,andinnaturalareas.Thesearetheproductsofchoiceformosttreatments.
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
surface filmsareusedtocontrolmosquitopupaebypreventingimmaturestagesfromobtainingoxygenfromthewater’ssurface.
Theseproductsdisruptthewater’ssurfacetensioncausingmosquitoestodrownandareidealsolutionsforswimmingpoolsandman-madecontainers.
ADuLt MosquitoesControllingadultmosquitoesismoredifficultandrequirestheuseofnon-specificproductsthatmayimpactotherinsects.Adultcontrolmaybecomenecessaryifmosquitopopulationsarehighanddiseasetransmissionisoccurringinanarea.Vectorcontroldistrictsselectproductsshowntobesaferfortheenvironmentandrequireuseoftheleastamountofpesticide.
Pyrethrumsortheiranalogsareappliedasanultra-lowvolumefogintotheairintheeveningsorearlymorninghourswhenmosquitoesaremostactive.
Becausedropletsizeissosmallanditisappliedwhenmostotherinsectsareinactive,fewernon-targetspeciesareimpacted.
Adult Aedes mosquitoes are aggressive daytime-biters and significant vectors of disease like dengue virus, yellow fever, and chikungunya worldwide.
BACkYArD reMeDies FACTORFICTION?• Manyelectronicdevicesclaimtorepelmosquitoeswithhigh
frequencysoundsthatmimictheirnaturalpredators;howeverthereisnoscientificsupportfortheseclaims.
• Bug‘zappers’,eventhoseusingmosquitoattractants,arenoteffectiveagainstmosquitoes.
• Citronellacandles/oillampsmayprovidebenefitoveralimitedareabutshouldnotbereliedupontoprotectusersfrombites.
• Mosquitotrapswillattractandcaptureapercentageofthemosquitoeshowevertheyareexpensivetopurchaseandmaintain.Theyworkbestwhenplacedattheperipheryoflargepropertiesinareaswheremosquitonumbersarehigh.
• Mosquito-repellingplantsarenoteffectiveatkeepingmosquitoesfromyouryard.
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
10 (626)814-9466
ir3535® IR3535®,alsocalledMerck3535,isregisteredwiththeEPAasabiopesticide,buthasbeenusedasasyntheticrepellentinEuropeforover20yearswithnosignificantharmfuleffects.
IR3535®wasapprovedforuseintheUnitedStatesin1999,andiscurrentlyavailableinaerosol,pumpspraysandwipes.
WhileEPArecognizestheuseofIR3535®assafeforadultsandchildren,be advised that it is an eye irritant.
RepelsMosquitoes Yes
RepelsTicks Yes
AgesforChildren Over6months
hours of Protection
Against Mosquitoes
Against ticks
Lessthan10%formula
2–4hours* 2–4hours*
15–20%formula
4–6hours* X
20%ormoreformula
6–8hours* 8–12hours*for some products
About repellentsChooseandusearepellentcontainingoneofthefollowingactiveingredientssoyoucanspendtimeenjoyingtheoutdoorsknowingyouareprotectedfrombitinginsectsandthediseasestheymaytransmit.
Deet DEET–basedrepellentshaveprovidedeffective,dependableprotectionsincethe1950s.
RepellentscontainingDEETareavailableinvariousconcentrationsthatrepelinsectsequallywellforthelengthoftimetheyareneeded.
DEET–basedproductsareavailableinawidevarietyofforms,includingaerosolandpumpspraysaswellaswipes.
DEET is the most effective and best–studied repellent available.
RepelsMosquitoes Yes
RepelsTicks Yes
AgesforChildren Over2months
hours of Protection
Against Mosquitoes
Against ticks
Lessthan10%formula
1–2hours*† 1–2hours*for some products
15–20%formula
2–6hours*† X
20–25%formula
5–8hours*† X
25–95%formula
6–10hours*for most products
2–4hours*for some products
95%ormoreformula
8–10hours* 5–10hours*for most products
* Theseprotectiontimeshavebeenapprovedforproductlabels.ThesetimesarebasedonthetechnicalinformationprovidedtotheEPAbythecompaniesontheeffectivenessoftheproductagainstmosquitoesand/orticks.Timeframeswereconsolidatedforallbrandswiththesamepercentageformulas.
X An“X”indicatesthatthemajorityofrepellentproductinthiscategoryhasnotbeenregisteredforprotectionfromticks.
† InformationprovidedbytheCentersforDiseaseControlandPrevention.
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
oil of Lemon eucalyptus/PMD OilofLemonEucalyptusisanaturalplant–basedrepellentthatisderivedfromtheoiloftheleavesoftheEucalyptus citidoratree.
RepellentscontainingoiloflemoneucalyptusprovideprotectionsimilartothatofproductscontaininglowconcentrationsofDEET.
Theseproductstendtohaveastrongbotanicalsmellandareavailableinawidevarietyofformulations,includingpumpspraysandlotions.
RepelsMosquitoes Yes
RepelsTicks Yes
AgesforChildren Over3years
hours of Protection
Against Mosquitoes
Against ticks
20%ormoreformula
2–6hours*† 6hours*for some products
Picaridin/kBr 3023 PicaridinisasyntheticrepellentdevelopedInthe1990sthathasbeencommerciallyavailableintheUnitedStatessince2005.Picaridiniscolorless,nearlyodorless,andisavailableinmultipleformulations.Itprovideslong–lasting,effectiveprotectionsimilartothatofproductscontainingidenticalconcentrationsofDEET.
BeadvisedthatnospecificrecommendationsregardingtheuseofPicaridinonchildrenhavebeenissuedbythemanufacturersortheCDC.
RepelsMosquitoes Yes
RepelsTicks Maybe
AgesforChildren n/a
hours of Protection
Against Mosquitoes
Against ticks
Lessthan10%formula
1–2hours† X
15%formula 2–4hours* X
Choose the right repellent for your activity
DEET,IR3535®
• ExtendedHikes
• OvernightCamping
OilofLemonEucalyptus
• SittingatthePark
• LightYardWork
• StrollAroundtheNeighborhood
PICARIDIN,DEET,IR3535®
• HeavyYardWork
• Barbecues
• LateNightOutdoorActivity
• OutdoorFestival
SomeformulationsofDEET
• Waterplay
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
12 www.sgvmosquito.org
reduce, reuse & recycle Water resPonsiBLYCapturingandstoringwaterhasbecomeincreasinglyimportantascommunitiesfacethethreatofwatershortagescausedbydroughtandwaste.Mosquitoeswillreadilyreproduceinwatercapturedevices,increasingtheriskofdiseasetransmissiontohumansandanimalsinthearea.Wemustconsiderallfactorsaswestrivetomaintainasustainableandhealthyenvironment.
Privatepropertyownersandhomeownerassociations(HOAs)mustmaintainwaterstorage/infiltrationdevicesinstalledontheirproperty.Toensureregularinspections,pleasereporttheirlocationandanymosquitoproblemspromptlytotheDistrict.
rAin BArreLs•Tightlyscreenallopeningsonrainbarrelswith1/16thinchmeshtoprohibitmosquitoentry.Checkregularlyandreplacetornordegradedscreens.
•Removewaterthatpoolsonthelidatleastonceweekly
•Keepguttersanddownspoutscleanandfreeofdebris
WAter tAnks (Cisterns)•Cisterns(aboveandbelowground)mustbetightlysealedtokeepmosquitoesout.
•Coverallinlets,outlets,andventswithtight-fitting1/16thinchmeshscreening.Inspectregularlytoensuretherearenocracksandsealsremainintact.
• Thecisternmustbeaccessibleforperiodicmaintenanceandinspectionformosquitobreeding.
Best MAnAgeMent PrACtiCes (BMPs) For Mosquito ControLStormwaterretention/treatmentdevicesmustbedesignedandproperlymaintainedtominimizemosquitoproduction,useofmosquitolarvicides,mosquito-bornediseasetransmission,andotherpublichealthissues.
•Selectandmaintainproperslopeforallwaterconveyances
•Ensureswales,ditches,andraingardensaremaintainedproperlyanddraincompletelywithin3-4days
•Thinemergentvegetationandremovesiltannuallyfromstormwaterdetentionbasins.
•Selectnative,low-growingvegetation.Avoidcattailsor
otherinvasivespeciessuchascreepingwaterprimrose,waterhyacinth,andparrotfeatherwhichgrowrapidly,canbedifficulttomaintain,andprohibiteffectivemosquitocontrolandinspection.
•Undergroundvaults/sumpsmustbecleanedoutregularly.Selectdevicesdesignedtodraincompletely.
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
Canine(Dog)HeartwormDiseaseisaseriousandsometimesfatalconditionindogscausedbytheroundwormDirofilaria immitisthatliveswithinthedog’sheartandlungs.Heartwormaffectscoyotes,foxes,dogs,andrarelycats,andistransmittedbymosquitoes,particularlytheWesterntreeholemosquito(Aedes sierrensis).
Mosquitoes Can Make Your Pets sick too!
BioLogY Adultheartwormsare6-12incheslongandcanreducebloodflowtothepointthattheheart,lungs,liver,andkidneysofcaninesaredamaged.Symptomsareusuallynotapparentuntilafterdamagehasbeendone.Advancedsymptomsofheartworminclude:rapidtiring,panting,chronicsoftdrycough,listlessness,andweightloss.
Mosquitoesbecomeinfectedandcantransmitheartwormafterfeedingonaninfecteddog,fox,orcoyote.Humanscannotdevelopheartwormevenifbittenbyaninfectedmosquito.
Prevention Itisusuallyimpossibleformosquitocontrolagenciestoeliminatetreeholemosquitoesfromaproblemareabecauseofthedifficultyinlocatingandaccessingbreedingsources.Immaturetreeholemosquitoesdevelopinthewaterthatcollectsinrotholesofmaturetrees,oldtires,cans,buckets,andothercontainers.Treeholemosquitoesaremostcommoninheavilywoodedareas.
Homeownersshouldexaminetreesandtreestumpsontheirpropertyforrotholes,cavities,andcrotchesthatcanholdwater.Ifholesarefound,consultanarboristtodeterminethebestwaytocorrecttheproblem.Holesmaybefilledwithsandorwaterabsorbinggelpolymers(polyacrylamide).Eliminateotherbreedingsourcesbyemptying,turningupsidedown,orthrowingawaycontainersthatholdwater.
Pet Prevention
Petownersshouldconsultwiththeirveterinarianabouttestingandpreventativemedicationsfordogs,especiallythosethatfrequentlyspendtimeoutdoors.
Canineheartwormiscurableifdiagnosedintheearlystages.
Dog heart with heavy worm infestation.
Mosquitoes SanGabrielValleyMosquito&VectorControlDistrict
14 www.sgvmosquito.org
insects that resemble MosquitoesTheSanGabrielValleyishometonumerousinsectsthatcloselyresemblemosquitoes.Manyoftheseinsectsemergeinlargenumbersduringtheearlyspring,alarmingthepublic.Thefollowingareinsectsthatareoftenmistakenformosquitoes.
MiDges
Midgesaresmall,grayishcoloredfliessimilarinsizetomosquitoes.Mostspeciesdonotbiteorposeahealthrisk,butcanbeaseriousnuisance,particularlyincommunitiesadjacenttolargeaquatichabitats.Tiny“no-see-ums,”however,arewellknownfortheirpainfulburningbites.Somepeoplemaybesensitivetomidgesandexperienceallergicreactions.
Immaturemidgesliveindamporsubmergedsoilsandareoftenanimportantsourceoffoodforaquaticpredators.Adultmidgesareshort-livedandweakflyers.Duringpeakemergence,massiveswarmsmayappearlikecloudsofsmokefromafar,andwhenatrest,cancoverhouses,cars,andotherstructures.
Personalprotectionisthebestdefenseagainstbitingmidges;wearprotectiveclothingsuchaslongsleevesandpants,andapplyrepellenttoexposedskinwhentheseinsectsarepresent.Todiscouragecongregationsofadults,movelightsawayfromdoorways,windows,andpatios,andreplacemercuryvaporlightswithyelloworsodiumvaporlights.
Midge
Actual size
Midgesaregenerallyabout3/8”atfulladultsize.
Swarming Midges
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SanGabrielValleyMosquito&VectorControlDistrict Mosquitoes
CrAne FLies
Oftencalled“mosquitohawks,”harmlesscranefliesaremuchlargerthanmosquitoesandcannotbiteortransmitanydiseasestopeople.Cranefliesaretan,brownorreddishincolorwithlonglegsandslenderbodiesreaching1
to3inchesinlength.Thelarvaeliveinmoistsoil,muddywater,ordecomposingmaterial.
Thesenon-bitinginsectsareshort-livedanddonotconstituteahealthproblembutcanbeannoyingwhenfoundinsidehomesorinlargenumbers.Iftheygetindoors,theyshouldbereleasedbackoutsidesincecranefliesareanimportantseasonalfoodsourceforbirds.
BLACk FLY
Oneofthemostirritatingpests,thesesmallbitingfliesoftenappearinourfoothillsingreatnumbersduringthespringandsummermonths,andhavemovedintourbanareaswiththeproliferationofbackyardpondsandwaterfeatures.
Likemosquitoes,theseinsectsbitehumansandothermammalstoobtainbloodproteinsnecessaryforeggdevelopment.Locally,blackfliesdonottransmitdisease,butcancauseextremediscomfort,allergicreaction,andirritationduetotheirbitinghabitsand/orgreatnumbers.
ControL AnD ProteCtionBlackfliesbreedinflowingriversandstreams,irrigationditches,andbackyardwaterfeatures.ControleffortsaredirectedattheblackflylarvaebyinterruptingwaterfloworusingBti/Bsproductswhennecessary.Inpondsandfountains,turnoffpumpsonceaweekfora24hourperiodtohelpcontrolpopulations.
AvoidbitesbywearingprotectiveclothingandusingDEET-basedrepellents,especiallyalongthehairlineandaroundears.
Crane Fly
Black Fly
Actual size
Blackfliesaregenerallyabout1/4”atfulladultsize.
Actual size
CraneFliescanbefrom1”to3”dependingonspecies.
About the san gabriel valley Mosquito & vector Control DistrictThe District was founded in 1989 to protect residents frommosquito-bornediseasethroughpubliceducation,surveillance,andcontrolofmosquitoes.
AstheDistrictevolved,additionalprogramswereadded.In1997,the Board of Trustees approved a full vector surveillance andcontrolprogram.
Surveillance for vector-borne diseases include St. Louisencephalitis,westernequineencephalomyelitis,WestNilevirus,plague,murinetyphus,hantavirus,arenavirus,andLymedisease.
District services are provided through an Integrated VectorManagement (IVM) approach which incorporates significantmeasures aimed at protecting the environment. The Districtpromotescooperationandcommunicationwithpropertyowners,residents, social and political groups, and other governmentalagenciestoaidinthoseefforts.Astrongcommitmenttopubliceducationiscriticaltoachievingthesegoals.
san gabriel valley Mosquito & vector Control District1145N.AzusaCanyonRoad•WestCovina,CA91790(626) 814-9466 • www.sgvmosquito.org
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