chapter 23 the pesticide dilemma. overview of chapter 23 o what is a pesticide? major kinds of...
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Chapter 23Chapter 23The Pesticide DilemmaThe Pesticide Dilemma
Overview of Chapter 23Overview of Chapter 23
o What is a Pesticide?What is a Pesticide?• Major Kinds of PesticidesMajor Kinds of Pesticides
o Benefits and Problems With PesticidesBenefits and Problems With Pesticideso Risks of Pesticides to Human HealthRisks of Pesticides to Human Healtho Alternatives to PesticidesAlternatives to Pesticideso Laws Controlling Pesticides UseLaws Controlling Pesticides Useo The Manufacture and Use of Banned The Manufacture and Use of Banned
PesticidesPesticides
What is a PesticideWhat is a Pesticide
o Broad spectrum pesticideBroad spectrum pesticide• A pesticide that kills a variety of organisms, A pesticide that kills a variety of organisms,
not just the targeted organismsnot just the targeted organisms
o First generation First generation pesticidepesticide• Inorganic compoundsInorganic compounds
• Lead and mercuryLead and mercury• Botanicals- plant Botanicals- plant
derived pesticidesderived pesticides• Nicotine and pyrethrinNicotine and pyrethrin
What is a PesticideWhat is a Pesticide
o Second generation pesticideSecond generation pesticide• Synthetic poisonSynthetic poison• Ex: DDTEx: DDT
Major Groups of InsecticidesMajor Groups of Insecticides
o Chlorinated HydrocarbonsChlorinated Hydrocarbons• Organic compound containing ChlorineOrganic compound containing Chlorine• Ex: DDTEx: DDT• Slow to degrade and persist in the Slow to degrade and persist in the
environmentenvironment• Banned or largely restrictedBanned or largely restricted
o OrganophosphatesOrganophosphates• Organic compounds that contain phosphorusOrganic compounds that contain phosphorus• Most poisonous insecticideMost poisonous insecticide• Do not persist as long as chlorinated Do not persist as long as chlorinated
hydrocarbonshydrocarbons
o CabamatesCabamates• Derived from cabamic acidDerived from cabamic acid
Major Kinds of HerbicidesMajor Kinds of Herbicides
o Selective HerbicidesSelective Herbicides• Kill only certain types of plantsKill only certain types of plants• Can be classified to the type of plant they Can be classified to the type of plant they
killkill• Broad-leaf herbicidesBroad-leaf herbicides• Grass herbicidesGrass herbicides
• Ex: 2,4-DEx: 2,4-D
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Benefit: Disease controlBenefit: Disease control• Fleas, lice and mosquitoes carry diseaseFleas, lice and mosquitoes carry disease• Malaria- Malaria-
mosquito bornmosquito born• 2.7 million people 2.7 million people
die each yeardie each year• Few drugs Few drugs
available, so available, so focus is on killing focus is on killing mosquitoesmosquitoes
• DDTDDT
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Benefit: Crop Benefit: Crop ProtectionProtection• Pests eat and destroy Pests eat and destroy
1/3 of world’s crops1/3 of world’s crops• Farmers save $3 to $5 Farmers save $3 to $5
for every $1 they for every $1 they invest in pesticidesinvest in pesticides
o Problem: Evolution of Problem: Evolution of Genetic ResistanceGenetic Resistance• Pest populations are Pest populations are
evolving resistance to evolving resistance to pesticides (right)pesticides (right)
o Pesticide TreadmillPesticide Treadmill• Cost of applying pesticide increases Cost of applying pesticide increases
• Because they must be applied more frequently Because they must be applied more frequently or in larger dosesor in larger doses
• While their effectiveness decreasesWhile their effectiveness decreases• Because of increased genetic resistance in pestsBecause of increased genetic resistance in pests
o Resistance ManagementResistance Management• Strategies for managing genetic resistance Strategies for managing genetic resistance
in order to maximize the period in which a in order to maximize the period in which a pesticide is usefulpesticide is useful
• Delays the evolution of genetic resistanceDelays the evolution of genetic resistance• Refuge of untreated plantsRefuge of untreated plants
Pesticide ResistancePesticide Resistance
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Problem: Imbalances the EcosystemProblem: Imbalances the Ecosystem• Spraying to kill insects can affect birds, Spraying to kill insects can affect birds,
rabbits, etc.rabbits, etc.• Despite 33-fold increase in pesticides since Despite 33-fold increase in pesticides since
the 1940s, crop loss has not really changedthe 1940s, crop loss has not really changed
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Problem: Creation of New PestsProblem: Creation of New Pests• Infestation of red scale insects on lemons Infestation of red scale insects on lemons
after DDT sprayed to control another pestafter DDT sprayed to control another pest
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Problem: Persistence, Bioaccumulation, Problem: Persistence, Bioaccumulation, and Biological Magnificationand Biological Magnification• BioaccumulationBioaccumulation
• The buildup of a persistent pesticide or other The buildup of a persistent pesticide or other toxic substance in an organisms bodytoxic substance in an organisms body
• Biological magnificationBiological magnification• Increased concentration of Increased concentration of
toxic chemicals in tissues toxic chemicals in tissues of organisms at higher of organisms at higher trophic levelstrophic levels
• Ex: Peregrine falcons Ex: Peregrine falcons (right)(right)
Benefits and Problems with Benefits and Problems with PesticidesPesticides
o Problem: Mobility in the EnvironmentProblem: Mobility in the Environment• Do not stay where they are appliedDo not stay where they are applied• Move through soil, water and airMove through soil, water and air
Risk of Pesticides to Human Risk of Pesticides to Human HealthHealth
o Short-term Effects of PesticidesShort-term Effects of Pesticides• Handling food with pesticide residueHandling food with pesticide residue• Mild case: Mild case:
nausea, nausea, vomiting, vomiting, headachesheadaches
• Severe case: Severe case: damage to damage to nervous nervous system, system,
Risk of Pesticides to Human Risk of Pesticides to Human HealthHealth
o Long-term Effects of PesticidesLong-term Effects of Pesticides• Cancer- lymphomaCancer- lymphoma• Breast cancerBreast cancer• SterilitySterility• MiscarriageMiscarriage• Birth defectsBirth defects• Decreases body’s ability to fight infectionDecreases body’s ability to fight infection• Potential connection to Parkinson’s diseasePotential connection to Parkinson’s disease
Alternatives to PesticidesAlternatives to Pesticides
o Using cultivation methods to control pestsUsing cultivation methods to control pests• Interplant mixtures of plants (alternating rows)Interplant mixtures of plants (alternating rows)• Strip cuttingStrip cutting• Proper timing of planting, fertilizing, and Proper timing of planting, fertilizing, and
irrigating irrigating • Crop rotationCrop rotation
o Biological ControlBiological Control• Use of naturally occurring disease organisms, Use of naturally occurring disease organisms,
parasites or predators to control pestsparasites or predators to control pests• Must take care that introduced agent does not Must take care that introduced agent does not
attack unintended hostsattack unintended hosts
Alternatives to PesticidesAlternatives to Pesticides
o Pheromones and HormonesPheromones and Hormones• Can use pheromones to lure pests to trapsCan use pheromones to lure pests to traps• By applying insect hormones at wrong time By applying insect hormones at wrong time
in life cycle, insects can be killed offin life cycle, insects can be killed off
o Reproductive ControlsReproductive Controls• Sterilizing some of the membersSterilizing some of the members• Sterile male techniqueSterile male technique
Alternatives to PesticidesAlternatives to Pesticides
o Genetic ControlsGenetic Controls• Genetically Modified plants (GMOs)Genetically Modified plants (GMOs)
• BtBt toxin toxin• Potential problem: may affect non-target species Potential problem: may affect non-target species
(monarch butterfly)(monarch butterfly)
o QuarantineQuarantine• Restriction of the importation of exotic Restriction of the importation of exotic
plant and animal material that might plant and animal material that might harbor pestsharbor pests
• Effective, but not foolproofEffective, but not foolproof
Systems Approach- Integrated Pest Systems Approach- Integrated Pest Management (IPM)Management (IPM)
o IPMIPM• Combination of pest Combination of pest
control methods that control methods that keeps pest population keeps pest population low without economic low without economic lossloss
o Conventional Conventional pesticides are used pesticides are used sparingly when other sparingly when other methods failmethods fail
o Rice Production in IndonesiaRice Production in Indonesia
Systems Approach- Integrated Pest Systems Approach- Integrated Pest Management (IPM)Management (IPM)
IPM IPM IntroduceIntroduce
dd
Alternatives to PesticidesAlternatives to Pesticides
o Irradiating FoodIrradiating Food• Harvested food is expose to ionizing Harvested food is expose to ionizing
radiation, which kills many microorganismsradiation, which kills many microorganisms• Predominantly used on meatsPredominantly used on meats• Somewhat controversial due to potential Somewhat controversial due to potential
for free radicalsfor free radicals
Laws Controlling Pesticide UseLaws Controlling Pesticide Use
o Food, Drug, and Cosmetics Act (1938)Food, Drug, and Cosmetics Act (1938)o Pesticide Chemicals Amendment (1954)Pesticide Chemicals Amendment (1954)o Delaney Cause (1958)Delaney Cause (1958)o Federal Insecticide, Fungicide, and Federal Insecticide, Fungicide, and
Rodenticide Act (1947)Rodenticide Act (1947)o Food Quality Protection Act (1996)Food Quality Protection Act (1996)
Manufacture and Use of Banned Manufacture and Use of Banned PesticidesPesticides
o Some US companies still make banned Some US companies still make banned or seriously restricted pesticidesor seriously restricted pesticides• Product is exportedProduct is exported
o May lead to the importation of food May lead to the importation of food tainted with banned pesticidestainted with banned pesticides
o Global ban of persistent organic Global ban of persistent organic pollutantspollutants• Stockholm Convention on Persistent Stockholm Convention on Persistent
Organic Pollutants (2004)Organic Pollutants (2004)
Manufacture and Use of Banned Manufacture and Use of Banned PesticidesPesticides