Pesticides and Pest Control Grasshopper Gypsy moth caterpillar
Jan 25, 2016
Pesticides and Pest ControlPesticides and Pest Control
Grasshopper
Gypsy mothcaterpillar
Key ConceptsKey Concepts
Types and characteristics of pesticides Types and characteristics of pesticides
Pros and cons of using pesticides Pros and cons of using pesticides
Pesticide regulation in the US Pesticide regulation in the US
Alternatives to chemical pesticides Alternatives to chemical pesticides
PestsPests
Compete with humans for food Compete with humans for food
Invade lawns and gardens Invade lawns and gardens
Destroy wood in houses Destroy wood in houses
Spread disease Spread disease
Are a nuisance Are a nuisance
May be controlled by natural enemies May be controlled by natural enemies
Types of PesticidesTypes of Pesticides
Pesticides are chemicals that kill undesirable organisms.
Pesticides are chemicals that kill undesirable organisms.
Insecticides Insecticides
Herbicides Herbicides
Fungicides Fungicides
Rodenticides Rodenticides
Major Types of PesticidesType
Insecticides
Chlorinatedhydrocarbons
Organophosphates
Carbamates
Botanicals
Microbotanicals
Examples
DDT, aldrin, dieldrin, toxaphene, lindane, chlordane, methoxychlor, mirex
Malathion, parathion, diazinon, TEPP, DDVP, mevinphos
Aldicarb, Carbaryl (Sevin), propoxur,maneb, zineb
Rotenone, pyrethrum, and camphorextracted from plants, synthetic pyrethroids (variations of pyrethrum), rotenoids (variations of rotenone), and neonicotinoids(variations of nicotine)
Various bacteria, fungi, protozoa
Persistence
High (2–15 years)
Low to moderate (1–2 weeks), but some can last several years
Low (days to weeks)
Low (days to weeks)
Low (days to weeks)
Biologically Magnified?
Yes
No
No
No
No
Major Types of Pesticides
Type
Herbicides
Contact chemicals
Systemic chemicals
Soil sterilants
Fungicides
Various chemicals
Fumigants
Various chemicals
Examples
Atrazine, simazine, paraquat
2,4-D, 2,4,5-T, Silvex, diuron,daminozide (Alar), alachlor (Lasso),glyphosate (Roundup)
Tribulan, diphenamid, dalapon, butylate
Captan, pentachlorophenol, zeneb, methyl bromide, carbon bisulfide
Carbon tetrachloride, ethylene dibromide, methyl bromide
Persistence
Low (days to weeks)
Mostly low(days to weeks)
Low (days)
Most low (days)
Mostly high
Biologically Magnified?
No
No
No
No
Yes (for most)
First Generation PesticidesFirst Generation Pesticides
Primarily natural substances Primarily natural substances
Sulfur, lead, arsenic, mercury Sulfur, lead, arsenic, mercury
Plant extracts: nicotine, pyrethrum Plant extracts: nicotine, pyrethrum
Second Generation PesticidesSecond Generation Pesticides
Primarily synthetic organic compounds Primarily synthetic organic compounds
Broad-spectrum agents Broad-spectrum agents
Narrow-spectrum agents Narrow-spectrum agents
Persistence in the environment Persistence in the environment
Targets specific organism
Ideally, it would break down fast and turn into benign products.
It would stay in the area it was applied and not move around in the environment.
Narrow Spectrum PesticidesNarrow Spectrum Pesticides
Broad Spectrum Pesticides
Kills a variety of organisms, not just the target species.
Many are persistent in the environment.
Many decompose into harmful byproducts.
Many move through the environment and bioaccumulate.
Inorganic Pesticides
Extremely toxic to birds and fish, do not decompose, accumulate in soil and water
Chlorinated Hydrocarbons
Highly toxic to birds and fish, high persistence, most bioaccumulate
Types of PesticidesTypes of Pesticides
Types of PesticidesTypes of Pesticides
OrganophosphatesVarying toxicity to birds and fish,
low persistence, doesn’t bioaccumulate.
CarbamatesHighly toxic to birds, mild toxicity
to fish, low persistence.
Types of PesticidesTypes of Pesticides
BotanicalsHighly toxic to aquatic life and
bees, low persistence, doesn’t bioaccumulate.
Inorganic PesticidesInorganic Pesticides
Used before 1940’sContained lead, mercury and arsenicExtreme toxicityNatural processes do not decomposeAccumulate in soil and water Threat to most life.
Endosulfan: Highly toxic, restricted use
Chlorinated HydrocarbonsChlorinated Hydrocarbons
General Form:
Malathion:
OrganophosphatesOrganophosphates
Diazinon (Spectracide)
Nerve Agents:
Sarin
Tabrun
Broad spectrum pesticide family
Derived from carbamic acid
Usually not toxic to mammals
Usually low persistence
Usually does not bioaccumulate
CarbamatesCarbamates
AldicarbCommon Carbamates
Carbaryl
Natural organic compounds, from plants natural defense systems
Easily degraded by microorganisms in the soil; not very persistent
Toxic to aquatic organisms and bees.
BotanicalsBotanicals
BotanicalsPyrethrin I
Rotenone
Selective herbicides- specific target weeds
Nonselective, broad spectrum herbicides. Kill all vegetation
Broad leaf herbicides, kill all but grasses
Grass herbicides, other plants are generally safe.
HerbicidesHerbicides
2,4 D 2,4,5 T
Two forms of chlorophenoxyacetic acid
Common Broad Leaf HerbicidesCommon Broad Leaf Herbicides
2, 4 D and 2,4,5 T are similar to plants natural growth hormone, therefore they disrupt growth processes.
Most food grains are grasses. These herbicides are used extensively to kill weeds that compete with these crops.
2,4,5 T is now banned, because it is probably harmful to humans.
Common Broad Leaf HerbicidesCommon Broad Leaf Herbicides
The Case for PesticidesThe Case for Pesticides
Save human lives Save human lives
Increase food supplies and lower costs Increase food supplies and lower costs
Work better and faster than alternatives Work better and faster than alternatives
Health risks may be insignificant compared to benefits
Health risks may be insignificant compared to benefits
Newer pesticides are becoming safer Newer pesticides are becoming safer
New pesticides are used at lower rates New pesticides are used at lower rates
Ideal PesticidesIdeal Pesticides
Affects only target pests Affects only target pests
Harms no other species Harms no other species
Breaks down quickly in the environment Breaks down quickly in the environment
No genetic resistance No genetic resistance
Be more cost-effective than doing nothing Be more cost-effective than doing nothing
Grasshopper
Gypsy mothcaterpillar
European red mite
The Case Against PesticidesThe Case Against Pesticides
Genetic resistance Genetic resistance
Can kill non-target and natural control species Can kill non-target and natural control species
Can cause an increase in other pest species Can cause an increase in other pest species
The pesticide treadmill The pesticide treadmill
Pesticides do not stay put Pesticides do not stay put
Can harm wildlife Can harm wildlife
Potential human health threats Potential human health threats
600
500
400
300
200
100
1940 1950 1960 1970 1980 1990
Nu
mb
er o
f g
enet
ical
ly r
esis
tan
t in
sect
sp
ecie
s
Year
Neonicotinoids(1995)
Pyrethroids (1978)
Carbamates (1972)
Organophosphates (1965)
DDT/cyclodienes (1946)
MH
MH
JH
MH
JH
JH
MH
Pupa
Eggs
Larva
Black
Boll weevil
Pink bollworm
ranges overlap
Pesticide Regulation in the United StatesPesticide Regulation in the United States
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
Tolerance levels Tolerance levels
EPA Evaluation of chemicals EPA Evaluation of chemicals
Inadequate and poorly enforced Inadequate and poorly enforced
Food Quality Protection Act (FQPA) Food Quality Protection Act (FQPA)
Alternate Ways to Control PestsAlternate Ways to Control Pests
Economic threshold Economic threshold
Adjusting cultivation practices Adjusting cultivation practices
Use genetically-resistant plants Use genetically-resistant plants
Biological pest control Biological pest control
Insect birth control Insect birth control
Hormones and pheromones Hormones and pheromones
Ionizing radiation Ionizing radiation
Hot water Hot water
Integrated Pest ManagementIntegrated Pest Management
Ecological system approach Ecological system approach
Reduce pest populations to economic threshold
Reduce pest populations to economic threshold
Field monitoring of pest populations Field monitoring of pest populations
Use of biological agents Use of biological agents
Chemical pesticides are last resort Chemical pesticides are last resort
Why is Integrated Pest Management not more widely used?Why is Integrated Pest Management not more widely used?
Requires expert knowledgeSlower than conventional pesticidesInitial costs may be highHindered by government subsidies
Requires expert knowledgeSlower than conventional pesticidesInitial costs may be highHindered by government subsidies