An acre of mud flats would be measured into a rectangular field. Slaves would clear the land, chopping down and burning or removing any trees. Oxen were the only draft animals that might be used to assist, but they had to wear a special boot or else they would sink in the muck. Using only picks and shovels, slaves excavated a five-by-five foot ditch through the clearing that would serve both as the canal that brought tidal waters to the field and its main drain. The slaves used the muddy soil they had excavated to form a levee as high as six feet tall around the field. Slaves constructed sluice gates (first of cypress plug trunks and later hanging floodgates) to drain the water from the field for sowing and flood it for cultivation. Typically the following season, the field would be divided into four ¼-acre sections. Slaves added quarter drains (secondary canals) and cleared stumps. With the extra weight of water-laden soil, the danger of snakes and alligators that had been stranded behind the levee, mosquitoes and hot summer temperatures, the slave's work was dangerous and exhausting.
Master Naturalist Mosquito Control
Life on the Coast: The Necessity of Mosquito Control Rosmarie Kelly, PhD MPH Public Health Entomologist Georgia Department of Public Health Atlanta, GA email@example.com 404-408-1207
Overview• Saltmarsh, freshwater, and mosquitoes• Brief history of coastal mosquito-borne diseases• Mosquito control – Some history – Mosquito control today – Some data• Surveillance – Why do it – Some basics (field work) 2
A CDC egg survey estimated that the dredgespoil areas have a breeding potential of 100million mosquitoes per acre. 6
The coastal marsh is not a “bad” environment. Over 90% ofthe salt marsh does not breed mosquitoes…only the highmarsh areas that trap water after extreme high tides orsignificant rainfall; ie. the areas of the marsh that do notflush with the daily tides. 7
Mosquito Oviposition Habitat• There are two general categories within which mosquito breeding habitats exist: – natural mosquito breeding habitats – man-made mosquito breeding habitats• Female mosquitoes lay their eggs either on water or on soils that are periodically flooded.• These breeding areas can be found in habitats that exist naturally, such as within a pond or flood plain, or in habitats that have been created by humans, such as bird baths, water-filled tires, or catch basins. 8
WHAT MAKES A MOSQUITO? A long piercing-sucking proboscis, with scales on it! Scales on the wings and body 3 basic body parts Head Thorax 2 (=one pair) wings 6 (= 3 pairs) legs Abdomen ~60 species are found in Georgia ~12 are actually a human problem 10
Larvae (5-10 days) Pupae (1-2 days) Egg (2 days - live ~1 month months)Life Cycle of Emerginga Mosquito Adult 13
WHAT DO THEY EAT?Plant juices & nectarFemales also need blood from other animals 14
WHY DO THEY NEED YOUR BLOOD?They use the blood tohelp develop eggs And now there will be more mosquitoes! 15
• Prior to the Civil War, the fertile delta bottomlands of the lower Altamaha basin were cleared, drained, ban ked and irrigated for the cultivation of rice, the primary staple crop of the Georgia and South Carolina tidewater section. 16
The marshy fields where rice was grown were breedinggrounds for mosquitoes carrying diseases such asmalaria and yellow fever. 18
The semi-tropical climate that made the Lowcountry such an excellent place forrice production also made it vulnerable to the spread of malaria and yellow fever.Anopheles quadrimaculatus is historically the most important vector of malaria inthe eastern United States. Many regions have natural populations of An.quadrimaculatus with predominant populations occurring in the rice growingregions due to cultural growing practices. Fresh water is regularly added to ricefields. Anopheles quadrimaculatus oviposit soon after fresh water has beenadded. 19
What is Yellow Fever? Sylvatic cycle Urban cycleA mosquito-borne viral disease ofhumans. Aedes aegypti is themost common vector.Initial symptoms includefever, headache, vomiting andbackache. yellow fever had a mortality rate of ~80%As the disease progresses, thepulse slows and weakens, and Rural cyclebleeding of the gums and bloodyurine occur. 21Jaundice may also occur.
Even in the absence ofdiseases, mosquitoes can become soabundant that they cause disruptions incommunity services and cause severestress in the affected local human, petand livestock populations. 22
In 1817 the City ofSavannah, which alsosupported a large ricegrowingculture, approved anordinance authorizingthe City to buy the rightof culture from wet todry from thesurroundinglandowners.From 1817 to 1829 the City records show the health of its citizens wasCity had expended much improved.$72,537 so that only dryrice field culture would This successful reduction in mosquitobe practiced on the breeding sites was likely the first timeadjacent lands. that local tax monies were expended to control mosquitoes in the New World. 24
Mosquito-control operations are targeted against threedifferent problems:• Nuisance mosquitoes bother people around homes or in parks and recreational areas;• Economically important mosquitoes reduce real estate values, adversely affect tourism and related business interests, or negatively impact livestock or poultry production;• Public health is the focus when mosquitoes are vectors of infectious disease. 25
To successfully control mosquitoes it is important to know:1. Which mosquito species are locallyimportant as the primary source ofintolerable annoyance or as vectors ofdisease.2. Where the breeding sites of thesemosquito species are located.3. When the mosquitoes are developingin these breeding sites and when theemergence of adult mosquitoes willtake place.4. What mosquito control measures areneeded and can be appliedeffectively, economically, and safelywith minimal disruption to the localenvironment.5. How much funding will be requiredto coordinate and execute the plan. 26
INTEGRATED MOSQUITO MANAGEMENT "A process consisting of the balanced use of cultural, biological, and least-toxic chemical procedures that are environmentally compatible and economically feasible to reduce pest and disease-vector populations to a tolerable level"THIS DOES NOT IMPLY THAT PESTICIDES SHOULD NOT BE USED 27
Best Management Practices Integrated Mosquito ManagementSurveillanceSource ReductionAdult and/or Larval ControlCommunity EducationMapping / Record Keeping 28
Without surveillance, mosquito control becomes a matter of luck.With surveillance, mosquito control becomes more targeted, more effective, and more economical. 29
Source Reduction• Modification of water habitats, including: – Ditching – Clearing vegetation – Filling low areas – Emptying containers – Cleaning gutters• This is the best method to use when dealing with container breeding mosquitoes. 30
Larviciding• Larviciding is a general term for killing immature mosquitoes by applying agents, collectively called larvicides, to control mosquito larvae and/or pupae.• It can include the use of natural enemies: – Dragonfly naiads – Mosquito Fish (Gambusia) 31
Some Larviciding History• Waste oil or diesel oil products were implemented to control mosquitoes in the early 1800s• Paris green dust, an arsenical insecticide, was developed as a larvicide in 1865 and, along with undiluted diesel oil, was used through the 1960s• Larviciding became prominent when implemented as an area-wide malaria control procedure in the early 1900s• After 1945, DDT, a chlorinated hydrocarbon compound, was used as both an adulticide and a larvicide - mosquitoes became resistant to DDT, and its use was discontinued in the late 1950s 32
Some Larviciding History• In the 1950s, malathion, an organophosphate, was used increasingly to control both larval and adult mosquitoes - soon, resistance to malathion was observed in saltmarsh mosquitoes.• Products currently available for use in larval control include: – Biological insecticides • Bacillus sphaericus • Bacillus thuringiensis israelensis • Natular – Temephos (OP) – Methoprene (IGR) – Oils – Monomolecular films 33
Adulticiding• Control of adult mosquitoes using pesticides• Products available for use include: – Organophosphates • Naled • Malathion/Fyfanon – Synthetic pyrethroids• Adulticides can be applied using: – ULV cold fogging – Thermal fogging – Barrier spray 34
Controlling Adult Mosquitoes • Time of dayTruck Mounted ULV – Mosquitoes must be Adulticiding present – Dark or close to dark – Temperature inversion • Conditions – The pesticide has to impinge upon the mosquito while aloft – The pesticide has to remain aloft but close to the ground • Calibration/Droplet size 35
Public Education• Media reports• Community Programs – Tip and toss (source reduction) – Neighborhood cleanup• Wear repellent (bite prevention)• School programs• Churches• Nursing Homes• Any place the public congregate 36
Mosquito Control Education• It is important to increase the knowledge of mosquito control workers and other professionals on matters related to mosquito biology, ecology, relationship to disease, and control.• Georgia Mosquito Control Association – Founded in 1977 – Annual meeting – Support for mosquito control programs – Sustaining member of the AMCA – PESP member• Georgia Department of Public Health – Mosquito surveillance – Mosquito ID classes• Extension Services 37
Record Keeping• Logging and tracking of citizen complaints and service requests.• Mosquito collection and trapping.• Insecticide applications and regulatory reports.• Tracking of work assignments, including detailed daily time and task recording.• Virus testing (sentinel flocks, mosquito pools, etc.) and related lab reporting.• Mosquito breeding and trap site mapping. 38
MAPPINGA picture is worth a thousand words.1. Map complaints2. Map service calls3. Map breeding sites4. Map anything useful and mappableUSEFUL TIP – Google Maps
Surveillance Data – McIntosh County McIntosh County Mosquito Surveillance species CDC Gravid Ae. albopictus 5 9 CDC Gravid Ae. vexans 2 70 An. crucians 47 An. quadrimaculatus 29 60 Cq. perturbans 7 50 count Cx. nigripalpus 12 40 Cx. quinquefasciatus 1 64 30 Cx. salinarius 10 20 Oc. atlanticus 2 10 Oc. japonicus 1 Oc. sollicitans 27 6 0 Ae. vexans An. crucians Cx. salinarius Oc. japonicus Cx. nigripalpus Cq. perturbans Ps. columbiae Ae. albopictus Cx. quinquefasciatus Oc. sollicitans Oc. triseriatus Oc. atlanticus An. quadrimaculatus Oc. triseriatus 1 Ps. columbiae 4 Oc. taeniorhynchus 8767 93GRAND TOTAL 8914 173 Species 40
Surveillance Data – McIntosh County Surveillance Data Ae. albopictus Ae. vexans An. crucians An. quadrimaculatus Cq. perturbans Cx. nigripalpus Cx. quinquefasciatus98% Cx. salinarius Oc. atlanticus Oc. japonicus Oc. sollicitans Oc. taeniorhynchus saltmarsh Oc. triseriatus mosquito Ps. columbiae 41
Light Traps• USE – general surveillance for host-seeking mosquitoes• Used in the EEE surveillance program• USEFUL for monitoring most nuisance species• NOT USEFUL for monitoring WNV
Larval Surveillance – “get them before they get you” 47
WHY MOSQUITO SURVEILLANCE?•Surveillance is used to define the nature and extent of themosquito problem.•Surveillance is used to gauge daily mosquito control needs.•It provides a basis for evaluating the effectiveness of controloperations.•It provides a basis for evaluating the potential fortransmission of mosquito-borne diseases.
Mosquito SurveillanceMosquito surveillance is the cornerstone of mosquito control.No mosquito control program can operate effectively without asurveillance program.Mosquito surveillance can reveal: •The species of mosquitoes that are active in a community •The presence of disease vector species •The presence of mosquitoes infected with arboviral diseases •The breeding habitats of the local species •The size of the local mosquito population •When to apply pesticides to control the mosquito population.
Knowing what mosquito species are present andwhere they are breeding is essential to a well-plannedmosquito control program.
ALL MOSQUITO SURVEILLANCE SHOULD HAVE APURPOSE:•MOSQUITO CONTROL – LARVAL OR ADULT•ARBOVIRAL SURVEILLANCE•PUBLIC EDUCATIONMOSQUITO SURVEILLANCE SHOULD NEVER BEDONE WITHOUT A SPECIFIC GOAL IN MIND.
http://health.state.ga.us/epi/vbd/mosquito.asphttp://www.GAmosquito.org Any Questions? 52