Pest ControlPest Control

Chapter 12Chapter 12APES 2010APES 2010

What are pesticides?What are pesticides? Chemicals that kill Chemicals that kill

pestspests Biocides- kill wide Biocides- kill wide

range of pestsrange of pests Herbicides- kill plantsHerbicides- kill plants Insecticides- kill Insecticides- kill

insectsinsects Fungicides- kill fungiFungicides- kill fungi

History of PesticidesHistory of Pesticides Every culture has used pesticidesEvery culture has used pesticides Modern era of pesticides began in Modern era of pesticides began in

1934 with development of DDT 1934 with development of DDT (Dichloro-Diphenyl-(Dichloro-Diphenyl-Trichloroethane)Trichloroethane)

Used in WWII to control parasites Used in WWII to control parasites & tropical disease& tropical disease

Was cheap, stable, soluble in oil, Was cheap, stable, soluble in oil, easily spread over wide areas.easily spread over wide areas.

High toxicity for target organisms- High toxicity for target organisms- kills 90% of target organisms in kills 90% of target organisms in single applicationsingle application

It was the “magic bullet”- the It was the “magic bullet”- the answer to our prayers… or was it?answer to our prayers… or was it?

History of PesticidesHistory of Pesticides Indiscriminate & excessive Indiscriminate & excessive

use of pesticides has causeduse of pesticides has caused Damage to ecosystemsDamage to ecosystems Harm to human healthHarm to human health Creation of “superbugs”Creation of “superbugs”

¾ of all pesticides are used in ¾ of all pesticides are used in Most Developed Countries Most Developed Countries (MDC) but rates in LDC are on (MDC) but rates in LDC are on the rise by 7-8%.the rise by 7-8%.

DDT was banned in US in the DDT was banned in US in the 1970’s. We can now only use 1970’s. We can now only use it in emergencies.it in emergencies.

DDT is still used in many other DDT is still used in many other countries- especially for countries- especially for control of mosquitoes.control of mosquitoes.

Children playing in DDT clouds at beach.

Types of PesticidesTypes of Pesticidesclassified based on chemical structureclassified based on chemical structure

1.1. Inorganic PesticidesInorganic Pesticides• Arsenic, copper, Arsenic, copper,

lead, mercurylead, mercury• Highly toxic & Highly toxic &

indestructableindestructable• Neurotoxin- single Neurotoxin- single

dose can cause dose can cause damagedamage

• May be used on May be used on seeds to deter seeds to deter rodentsrodents

Arsenic poisoning from infected water sources in Bangladesh

Types of PesticidesTypes of Pesticides

2.2. Natural organic Natural organic pesticidespesticides

• Nicotine, rotenoneNicotine, rotenone• BotanicalsBotanicals• From plantsFrom plants

Types of PesticidesTypes of Pesticides3.3. FumigantsFumigants

• Carbon tetrachloride, Carbon tetrachloride, carbon disulfidecarbon disulfide

• Become gases Become gases easily & penetrate easily & penetrate easilyeasily

• Used to sterilize soil Used to sterilize soil or deter rodent or deter rodent infestation in stored infestation in stored graingrain

• So dangerous, So dangerous, mostly bannedmostly banned

Types of PesticidesTypes of Pesticides4.4. Chlorinated Chlorinated

HydrocarbonsHydrocarbons• DDT, chlordane, aldrin, DDT, chlordane, aldrin,

dieldrin, toxaphene, dieldrin, toxaphene, paradichlorobenzene paradichlorobenzene (mothballs), (mothballs),

• Block nerve signalsBlock nerve signals• Fast & toxic, carcinogenicFast & toxic, carcinogenic• Biomagnify- stay in Biomagnify- stay in

ecosystemecosystem• Toxaphene kills goldfish Toxaphene kills goldfish

at 5 ppb- one of the at 5 ppb- one of the highest toxicities for any highest toxicities for any compoundcompound

Types of PesticidesTypes of Pesticides5.5. OrganophosphatesOrganophosphates

• Parathion, malathion, Parathion, malathion, DDVP, TEPPDDVP, TEPP

• From nerve gas researchFrom nerve gas research• Extremely toxic to Extremely toxic to

mammals, birds, & fishmammals, birds, & fish• One drop of TEPP on One drop of TEPP on

skin is lethalskin is lethal• Quickly degrade so much Quickly degrade so much

less persistent in less persistent in environmentenvironment

Types of PesticidesTypes of Pesticides

6.6. CarbamatesCarbamates• Carbaryl, MirexCarbaryl, Mirex• Similar to Similar to

organophosphatesorganophosphates• Very toxic to bees Very toxic to bees

• If bees die, our crop If bees die, our crop yields will decrease yields will decrease drastically due to lack drastically due to lack of pollination of pollination

Types of PesticidesTypes of Pesticides7.7. Microbial agents or Microbial agents or

Biological controls- Biological controls- • using live organisms or using live organisms or

their toxins instead of their toxins instead of pesticidespesticides

• Bacillus thuingiensisBacillus thuingiensis (Bt)- kills beetles, (Bt)- kills beetles, caterpillars by caterpillars by destroying their destroying their digestive tractdigestive tract

• Parasitic waspsParasitic wasps• Ladybugs eat aphidsLadybugs eat aphids• VirusesViruses

Benefits of PesticidesBenefits of Pesticides Reduce disease transmission by insect vectors Reduce disease transmission by insect vectors (DDT (DDT

sprayed to kill mosquitoes & prevent malaria, when sprayed to kill mosquitoes & prevent malaria, when stopped in 1964, malaria reappeared immediately)stopped in 1964, malaria reappeared immediately)

Which is more important? Protecting people or the Which is more important? Protecting people or the environment?environment?

If you had to choose between contracting masses of worms that If you had to choose between contracting masses of worms that will make you go blind before the age of 30 or a small chance of will make you go blind before the age of 30 or a small chance of cancer due to pesticide exposure it you live to 50 or 60, which cancer due to pesticide exposure it you live to 50 or 60, which would you choose?would you choose?

Reduce crop losses by two-thirds.Reduce crop losses by two-thirds. Farmers save $3-$5 for every $1 they spend on pesticides.Farmers save $3-$5 for every $1 they spend on pesticides. Lowers costs and increases crop qualityLowers costs and increases crop quality

Problems with PesticidesProblems with Pesticides Non-target organisms affected Non-target organisms affected

Potato aphid spraying killed Potato aphid spraying killed migrating robinsmigrating robins

Insecticide spraying in CA killed Insecticide spraying in CA killed salmonsalmon

Honeybees disappearingHoneybees disappearing Resistant individuals will develop due Resistant individuals will develop due

to natural selectionto natural selection Pesticide is killing off natural Pesticide is killing off natural

predators that help control bad predators that help control bad populationspopulations

Limited useful lifespan- can move far Limited useful lifespan- can move far from original application spot (next from original application spot (next slide)slide)

Persistant organic pollutants (POP’s) Persistant organic pollutants (POP’s) are very long lasting and dangerous. are very long lasting and dangerous. Banned in most countries but Banned in most countries but persistent in soil & waterpersistent in soil & water

Affect Human Health (see slide 15)Affect Human Health (see slide 15) Acute- poisoning & illnessAcute- poisoning & illness Chronic- cancer, birth defects, Chronic- cancer, birth defects,

degenerative diseasesdegenerative diseases

Pest resurgence leads to the use of higher doses or more toxic chemical use

The Grasshopper EffectThe Grasshopper Effect Many chemicals like Many chemicals like

chlorinated hydrocarbons chlorinated hydrocarbons evaporate from water & soil in evaporate from water & soil in warm areas & condense & warm areas & condense & precipitate in colder regions.precipitate in colder regions.

This happens over & over, This happens over & over, “hopping” northward until it “hopping” northward until it collects in polar regions.collects in polar regions.

Affecting top predators (polar Affecting top predators (polar bears, whales, & humans)bears, whales, & humans)

Some carcasses have to be Some carcasses have to be treated as toxic waste they are treated as toxic waste they are so “infected” with pesticide.so “infected” with pesticide.

Be familiar with “The Dirty Be familiar with “The Dirty Dozen”- Table on Dozen”- Table on toxin review sheettoxin review sheet

About Human Health…About Human Health…

Yaqui children in Mexico tested…Yaqui children in Mexico tested… Foothills children age 4-5 not exposed to Foothills children age 4-5 not exposed to

much pesticidemuch pesticide Valley children age 4-5 repeatedly exposed Valley children age 4-5 repeatedly exposed

Alternatives to PesticidesAlternatives to Pesticides Crop rotationCrop rotation keeps keeps

pest population low.pest population low. Using cover crops Using cover crops

keeps weeds downkeeps weeds down Provide habitat for Provide habitat for

natural predators natural predators (plant trees along (plant trees along edge of farm for birds edge of farm for birds which will eat bugs & which will eat bugs & provide windbreak provide windbreak which prevents which prevents erosion)erosion)

Alternatives to PesticidesAlternatives to Pesticides Biological controls-Biological controls- natural natural

predatorpredator Bacillus thuringiensis (Bt)- kills Bacillus thuringiensis (Bt)- kills

beetles & caterpillarsbeetles & caterpillars Ladybugs, praying mantises, Ladybugs, praying mantises,

waspswasps Ducks & geese in fields will Ducks & geese in fields will

eat insects & weed seed.eat insects & weed seed. Planting garlic or marigolds Planting garlic or marigolds

can deter pests.can deter pests. Release of sterilized males Release of sterilized males

(screwworms)(screwworms) Release of artificial hormones Release of artificial hormones

can disrupt life cycles can disrupt life cycles (mosquitoes)(mosquitoes)

Alternatives to PesticidesAlternatives to Pesticides Integrated Pest Management Integrated Pest Management

(IPM(IPM)- )- use preventative measures use preventative measures to encourage growth & diversity with to encourage growth & diversity with minimal use of chemical pesticidesminimal use of chemical pesticides

Vacuuming bugs off cropsVacuuming bugs off crops

Trap crops- Trap crops- mature before rest of mature before rest of field to attract pests, then sprayed field to attract pests, then sprayed heavily, destroy trap crop to prevent heavily, destroy trap crop to prevent spread to people or “real” crop.spread to people or “real” crop.

Educating farmers- Educating farmers- In Indonesia In Indonesia farmers were spraying fields about farmers were spraying fields about 3x a week whether planthopper pest 3x a week whether planthopper pest was present or not- made them was present or not- made them pesticide resistant. By educating pesticide resistant. By educating farmers about natural predators and farmers about natural predators and using pesticides sparingly, helped using pesticides sparingly, helped increase crop yields & save $ on increase crop yields & save $ on pesticidepesticide

Who regulates pesticide usage?Who regulates pesticide usage? Environmental Protection Agency (EPA)Environmental Protection Agency (EPA)

Regulates sale & usage under Regulates sale & usage under Federal Insecticide, Fungicide, Federal Insecticide, Fungicide, & Rodenticide Act & Rodenticide Act ((FIFRA) FIFRA) which mandates the “registration” of which mandates the “registration” of all pesticide products.all pesticide products.

Determines which pesticides are safe to use for humans & Determines which pesticides are safe to use for humans & environmentenvironment

Sets tolerance levels for residues that may remain in or on foods Sets tolerance levels for residues that may remain in or on foods marked in U.S. This falls under the marked in U.S. This falls under the Federal Food, Drug, and Federal Food, Drug, and Cosmetic Act (FFDCA).Cosmetic Act (FFDCA).

Department of Agriculture (USDA) & Food & Drug Department of Agriculture (USDA) & Food & Drug Administration (FDA)Administration (FDA) enforce pesticide use & tolerance enforce pesticide use & tolerance limits set by EPA. Can seize & destroy food shipments limits set by EPA. Can seize & destroy food shipments that violate.that violate.

What can you do at home?What can you do at home? Plant grass that can compete with weeds. Don’t worry about the Plant grass that can compete with weeds. Don’t worry about the

weeds- don’t we all love dandelions!weeds- don’t we all love dandelions! Repair screen doors to keep bugs out. Caulk windows, doors, etc to Repair screen doors to keep bugs out. Caulk windows, doors, etc to

keep rodents, roaches, ants outkeep rodents, roaches, ants out Clean up spills & remove garbage regularly; use flypaper, use borax Clean up spills & remove garbage regularly; use flypaper, use borax

for roachesfor roaches Kill aphids & other plant bugs by spraying with dilute detergent Kill aphids & other plant bugs by spraying with dilute detergent

solution. Order ladybugs or praying mantis cocoons.solution. Order ladybugs or praying mantis cocoons. Use beer to drown slugs in gardensUse beer to drown slugs in gardens Remove all sources of stagnant water to deter mosquitoes.Remove all sources of stagnant water to deter mosquitoes. If you must use pesticides use them in small amounts & only when If you must use pesticides use them in small amounts & only when

necessary; try not to use sprayersnecessary; try not to use sprayers Create mulch from your veggie scraps & kitchen waste & use as Create mulch from your veggie scraps & kitchen waste & use as

mulch to deter weeds.mulch to deter weeds.