the smell of malathion

DON’T YOU LOVE THE SMELL OF MALATHION IN THE

MORNING!

Rosmarie Kelly, PhD MPHPublic Health EntomologistGeorgia Division of Public HealthAtlanta, GA

ALTERNATIVE TITLE:ALTERNATIVE TITLE:Why All The Concern About Pesticides Anyway?

Topics of discussion:

•Integrated pest management

•Pre-history

•History

•Application to mosquito control

•Mosquitoes and Public Health

•Nuisance problems and quality of life

•Disease issues

•The BIG picture

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Integrated Pest Management (IPM)Integrated Pest Management (IPM)

IPM reduces dependence on pesticides by integrating non-IPM reduces dependence on pesticides by integrating non-chemical methods to help control or prevent pest chemical methods to help control or prevent pest populations.populations.

IPM Practices

•Identify the pest

•Use surveillance of some type to evaluate pest level

•Don’t make applications based on a calendar

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Anything that:

•Competes with humans, domestic animals, or desirable plants for food or water

•Injures humans, animals, desirable plants, structures or possessions

•Spreads disease to humans, domestic animals, wildlife or desirable plants

•Annoys humans or domestic animals

What is a pest?What is a pest?

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A Brief History of Pest Control:A Brief History of Pest Control:

The first farmers likely did not so much "control" as allow for pests - that is, they planted enough for themselves and the pests (deer, rabbits, insects, etc)

2500 BC: Ancient Sumerians used sulfur compounds to kill insects- earliest record of insect pest control

1500 BC: First descriptions of cultural controls especially the manipulation of planting dates

1200 BC: Botanical insecticides were being used for seed treatments and as fungicides in China. The Chinese were also using mercury and arsenical compounds to control body lice.

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1860 - First use of arsenical insecticide noted; use of Paris green mixed with flour as insecticide for Colorado potato beetle control.

1894 - First "spray calendar" invented.

A Brief History of Pest Control (cont):A Brief History of Pest Control (cont):

http://entweb.clemson.edu/pesticid/100years/100yrH.htmhttp://entweb.clemson.edu/pesticid/100years/100yrH.htm

lead arsenatelead arsenate

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1929: Pest resurgence after repeated applications of arsenical pesticides documented in Texas

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1939: Recognition of insecticidal properties of DDT

DDT was far less poisonous than the pre-WWII arsenic compounds.

The phenomenal results with DDT stimulated industry to look for related types of chemicals.

By the late 1940's, there were several other encouraging insecticides available.

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Time magazine ad for DDT

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BETTER LIVING THROUGH CHEMISTRY: The World Health Organization estimates that during the period DDT was used, approximately 25 million lives were saved.

1947: First documented case of pesticide resistance (common house fly resistant to DDT)

1950's-60's: Widespread development of resistance to DDT and other pesticides.


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TROUBLE IN PARADISE

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Rachel Louise Carson (1907-1964)

Master’s degree in zoology from Johns Hopkins University

American Marine Biologist1936 - Biologist US Bureau of Fisheries

Nature writer – 1950sCredited with advancing the global environmental movement1951 –Ocean Life Trilogy

The Sea Around UsThe Edge of the SeaUnder the Sea-Wind

Conservation Movement – 1950sProblems related to synthetic pesticides1962- Silent SpringLed to a nationwide ban on DDT - 1970

Posthumous award – Presidential Medal of Freedom

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Response to Silent Spring led to public policy changes in 1970's.

1967: Introduction of the term Integrated Pest Management by R.F. Smith and R. van den Bosch.

1969: US National Academy of Sciences formalized the term Integrated Pest Management.

1970's: Widespread banning of DDT.

The overriding theme of Silent Spring is the powerful—and often negative—effect humans have on

the natural world.

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Natural Enemies

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* A system utilizing multiple methods,* A decision making process,* A risk reduction system,* Information intensive,* Biologically based,* Cost effective, and* Site specific.* Multiple tactics

legal, cultural, physical, genetic, biological, chemical

What is IPM?What is IPM?

• Legal controlLegal control: following state and federal guidelines that are designed to prevent the spread of pests

• Cultural controlCultural control: using crop rotation, cultivation, sanitation, habitat modification, or removal of sources of pest infestation

• Physical controlPhysical control: using barriers, traps, trap crops; planting, fertilization, tillage, or harvest times

IPM Control Methods

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• Genetic controlGenetic control: using plant (and animal) varieties that are resistant to pest injury

• Biological controlBiological control: conservation or introduction of predators, parasites, and diseases that suppress or attack pests

• Chemical controlChemical control: select and use the least toxic, environmentally suitable pesticides in the lowest effective amounts to control pests

IPM Control Methods

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•Provides long term results

•Environmentally friendly

•Reduces unnecessary chemical use and its liability

•Reduces risk of pesticide resistance

•Proactive, not reactive

•Detects a potential pest problem before it's a major problem

•Provides a written record of pest activities and control actions •Promotes better community relationships

•Site-specific

BENEFITS

The damage boundary is the lowest level of injury that can be measured. This level of injury occurs before economic loss.

A basic IPM principle ensues from the damage boundary/economic damage relationship; it is that no injury level below the damage boundary merits suppression, but injury predicted to result in economic damage does.

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Damage ThresholdDamage Threshold

No control needed

CONTROL NEEDED

Another of the basic elements, the economic injury level, is the lowest population density that will cause economic damage. The EIL is the most basic of the decision rules; it is a theoretical value that, if actually attained by a pest population, will result in economic damage.

Therefore, the EIL is a measure against which we evaluate the destructive status and potential of a pest population.

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Economic Injury LevelEconomic Injury Level

The economic threshold (ET) differs from the EIL in that it is a practical or operational rule, rather than a theoretical one. It is the population density at which a control action should be initiated to prevent an increasing pest population from reaching the economic injury level.

Although measured in insect density, the ET is actually a time to take action, i.e., numbers are simply an index of that time.

The ET is the action threshold.

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Economic thresholdEconomic threshold

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•May be more expensive to implement - especially when first starting IPM

•Requires everyone to take an active role

•Requires more skill and knowledge than traditional pest control

•Additional paperwork and communication

•Requires on-going training

•Persistent attention needed

BARRIERS

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"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"

MOSQUITO MANAGEMENT

To successfully control mosquitoes it is important to know: 1. Which mosquito species are locally important as the primary source of intolerable annoyance or as vectors of disease.

2. Where the breeding sites of these mosquito species are located.

3. When the mosquitoes are developing in these breeding sites and when the emergence of adult mosquitoes will take place.

4. What mosquito control measures are needed and can be applied effectively, economically, and safely with minimal disruption to the local environment.

5.5. How much funding will be required to coordinate and execute How much funding will be required to coordinate and execute the plan. the plan.

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INVESTIGATIONINVESTIGATION

INSPECTIONIDENTIFICATIONMONITORING

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ACTIONACTION

TOLERANCE LEVELPREVENTIONCONTROL

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FOLLOW-UPFOLLOW-UP

Ware County Mosquito Surveillance

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500

1000

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2000

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3000

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4000

1 2 3 4 5 6

trap site

# P

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# Ps co

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PRESPRAY

POSTSPRAY

EVALUATIONEDUCATION

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Tracking the Elusive Mosquito,Tracking the Elusive Mosquito,

or Why Public Health (and the Public) Should Care About Mosquitoes and Mosquito-Borne Diseases.

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Epidemic transmission of West Nile virus (WNV) in Sacramento County, California, in 2005 prompted aerial application of pyrethrin, a mosquito adulticide, over a large urban area.

Statistical analyses of geographic information system datasets indicated that adulticiding reduced the number of human WNV cases within 2 treated areas compared with the untreated area of the county.

No new cases were reported in either of the treated areas after adulticiding; 18 new cases were reported in the untreated area of Sacramento County during this time.

Results indicated that the odds of infection after spraying were 6× higher in the untreated area than in treated areas, and that the treatments successfully disrupted the WNV transmission cycle.

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http://landresources.montana.edu/WNV/

Pesticide Risk Assessments

…Further, our results suggest that, based on human-health criteria, the risks from WNV exceed the risks from exposure to mosquito insecticides.

…Because of the limitations in efficacy and availability of both vaccines and therapeutic drugs, vector management often is the best tool that military personnel have against most vector-borne pathogens. … Overall, results indicate that health risks from exposures to insecticides and personal protective measures used by military personnel are low.

Therefore, we found no significant toxicological risks from typical usage of these topical insect repellents.

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http://landresources.montana.edu/WNV/

Pesticide Risk Assessments

…Nontargets exposed to adulticides included small mammals, birds, as well as aquatic vertebrates and invertebrates in a pond subject to receiving the chemical via drift and runoff. Risk quotients were obtained by comparing exposures to toxic endpoints. All risk quotients were low indicating that risks to ecological receptors most likely were small.

…assess acute impacts of mosquito adulticides (permethrin and d-phenothrin) and larvicides (Bacillus thuringiensis israelensis and methoprene) on non-target aquatic and terrestrial arthropods after a single application. …assess longer term impacts of permethrin on non-target terrestrial arthropods after multiple repeated applications. …nearly all of the responses evaluated for either study indicated few, if any, deleterious effects from insecticide application.

Every year, over two million people worldwide die from mosquito-borne diseases.

Mosquitoes cause more human suffering than any other organism.

Class Insecta All insects – 3 main body divisions, 6 legs Order Diptera All 2-winged flies Family Culicidae All mosquitoes

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human MALARIA

On a world-wide basis, malaria remains the most important human disease transmitted by mosquitoes.

• estimated 400 million human cases (mostly Africa & Asia)

• >2 million deaths annually

• in Africa, >1 in 20 children under 10 years old die from malaria

4 Plasmodium spp (protozoan)Anopheles spp mosquitoes

P. ovaleP. falciparumP. malariaeP. vivax

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Even in the absence of diseases, mosquitoes can become so abundant that they cause disruptions in community services and cause severe stress in the affected local human, pet and livestock populations.

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Misconceptions

•You can lead a chemical-free life

•Man-made chemicals are inherently dangerous

•Synthetic chemicals are causing cancers and other diseases

•Exposure to chemical mixes is a ticking time-bomb

•It is beneficial to avoid man-made chemicals

• Natural = Safe

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Rachel Carson stated that: “For the first time in the history of the world, every human being is now subjected to contact with dangerous chemicals, from the moment of conception until death.”

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“This statement is wrong: the vast bulk of the chemicals humans are exposed to are natural, and for every chemical some amount is dangerous”.

Bruce Ames

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Carson described fearful and insidious, but largely fictional, DDT harm to wildlife

BENFICIAL: Her book launched the modern environmental movement

DETRIMENTAL: “Tipping point” in campaign to create fear of DDT and other insecticides (the Bambi Effect)

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Rachel Carson claimed DDT was pushing the robin to brink of extinction.

FALSE: The robin was actually increasing in population abundance during years of maximum use of DDT.

Rachel Carson brought to the public’s attention the claim that DDT-induced eggshell thinning was driving the bald eagle to extinction.

NOT THE WHOLE STORY:•Long before advent of DDT, bald eagles already eliminated from most of the lower 48 states.

•Bald eagles had been eliminated by hunting, trapping and poisoning (known as “taking”).

•Bounties were paid for “taking” of eagles.

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EPA Hearings

“DDT is not a carcinogenic, mutagenic, or teratogenic hazard to man. The uses of DDT do not have a deleterious effect on freshwater fish, estuarine organisms, wild birds, or other wildlife. The evidence in this proceeding supports the conclusion that there is a present need for the essential uses of DDT”

Judge Edmund SweeneyApril 26, 197240 CFR 164.32

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William Ruckelshaus overruled the EPA judgment on DDT -Congressional Record, July 24 1972, pp. S11545-46

Never attended the DDT hearings Never read the transcript Refused to release materials used in his decision

Quote from a letter written to Allan Grant, president of the American Farm Bureau Federation, by William Ruckelshaus:

“Decisions by the government involving the use of toxic substances are political … The ultimate judgment remains political.” (April 26, 1979)

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“A decision to ban the production of DDT in the US, would result in a denial of the use of DDT to most of the malarious areas of the world. The available evidence on the very slight risks, if any, does not justify the US making a unilateral decision that would so adversely affect the future economic and social well-being of so many other nations of the world”

Centers for Disease Control and PreventionJuly 25, 1969

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Today is being commemorated around the globe as "World Malaria Day. …Thanks to Rachel Carson's ode to a non-existent natural wonderland allegedly devastated by toxic pesticides, DDT became the target of the anti-chemical lobby, and its use was virtually abandoned -- though late enough to spare the wealthy West from typhus and malaria. Left behind were the poor of sub-Saharan Africa and other tropical regions, and millions have paid the price for chemophobic ideologues who are themselves at no risk.

Gilbert Ross, M.D25 April 08

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…in 1999, the West Nile virus had just been discovered in a few discarded tires and birdbaths in the New York area. But when the City, under Mayor Giuliani, tried to aggressively eradicate the bugs, resistance cropped up - not to the pesticide, but from "consumer advocacy" groups like PIRG. The spraying was severely restricted. Guess what? West Nile Virus is now endemic throughout the continental United States, and hundreds have died, needlessly.


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…in California … a perfectly safe, pheromone-altering compound is also under attack, despite the fact that the insect it is designed to fight threatens the breadbasket of California agriculture, the central valley.

“Is what we are experiencing part of a sinister plan to poison (or worse) a large populace, who more and more, is choosing an alternative and chemical free lifestyle? It is unclear how much the government is aware of this plan, but it is clear that the government goes out of their way to deny and hide all serious reported health claims.”…“…I felt like the airplanes spraying chemicals were attacking my very right to exist and be here.”

Rami Nagel No Spray Coalition31 Dec 2007

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“The city councilors … are well-meaning, socially responsible people. And when they came across the huge threat posed to their constituents by dihydrogen monoxide they did what any elected official should do: they took steps to protect their community. A motion due to go before the city legislature proposed banning the potentially deadly substance from within the city boundaries.”

H2O

http://www.guardian.co.uk/world/2004/mar/24/usa.worlddispatch

the smell of malathion

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