Environ Final.docx

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Published on 19 Apr 2013
School
Western University
Department
Environmental Science
Course
Environmental Science 1021F/G
Professor
Food and Land III
Food and Soil Resources
Pests and Pesticides
Pest unwanted organism that interferes with human activities; subjective
"A weed is a plant whose virtues have not
yet been discovered" - Waldo Emerson
Pesticide kills or controls undesirable organisms
100 species (1%) cause 90% of the damage
Disturbs predator-prey cycles in natural ecosystems and polyculture
Pesticides: Types
1. Insecticides block reproduction, airways, nervous system
2. Herbicides disrupt plant growth and metabolism
3. Fungicides
4. Rodenticides
Pesticide History
Before pesticides
Crop rotation, vary planting times, plant diversity, hedgerows
Based on plants natural “instincts
First generation
Sulphur, lead, arsenic, mercury
Nicotine sulphate, pyrethrum, rotenone
Second generation
Synthetic organic compounds (eg DDT), broad- and narrow-spectrum, persistence
reduction, some natural
The Case For Pesticides
Saves human lives Malaria, bubonic plague, typhus
Increase food supplies and profits; lower costs
Work faster and better than alternatives
Health risk *may* be insignificant compared to benefits
3000-6000 death/yr (EPA)
New pesticides are safer and used at lower rates than older pesticides
The Case Against Pesticides:
What are the true costs?
Genetic resistance insects and plants
Kill non-target organisms, incl. natural predators
Can increase other pests
Harm wildlife
Pesticide movement
Human health threat; 20,00040,000 deaths
Environmental health threat
Still 6% decrease in yield loss to pests
Economic threshold of use
Use reduced without yield decrease
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Alternatives to Synthetic Chemical Pesticides
Some based on biomimicry, part of Integrated Pest Management (IPM)
1. Change cultivation practices (cultural)
2. Biological pest control
Insect birth control (hormones/pheromones)
Predators
3. Hot water
4. Genetically-resistant plants
Recall: associated problems
What Are the Environmental Issues?
Food Consumption After the Farmgate
Energy and waste:
Plant, irrigate, fertilize, apply pest control, harvest
Transport for processing
Store, clean, cook, mix, preserve, package
Transport to the grocery store
Keep food chilled/frozen, displayed
Transport and preparation at home/restaurants
Disposal transport
How much energy is used?
17% of US energy consumption used to get food to the table
18% of that for on-farm food production
82% of that for food processing, transportation, marketing and preparation!!!
Most energy is from non-renewable fossil fuels
Release GHG’s and other pollutants
How can you decrease the energy cost of your food?
Choose
locally/native/organically grown food
foods in season
less processed, whole foods
foods with less packaging
to eat less meat, especially red meat (lower trophic level = less energy waste) see next
slide
to compost
to garden
Food and Land IV
Forests, Invasive Species and Biodiversity
Managing and Sustaining Forests
Forests classified by age and structure
1. Old-growth forests (22%)
2. Second-growth forests (63%)
3. Tree farms/plantations (5%)
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Ecological Services of Forests
Carbon sink
Energy flow and nutrient cycling
Erosion protection
Air and water purification
Water control
Local and regional climate regulation
Wildlife habitat
Economic Services of Forests
Fuel wood
Lumber
Paper
Livestock grazing
Recreation
Jobs
Other resources (minerals, medicine, food)
Forest Types of the World
Classified by climate
Tropical
Temperate
Boreal (taiga)
Canada’s Forest Regions
Boreal - largest
Taiga
Aspen Parkland
Subalpine
Montane
Coastal
Columbia
Carolinian
Great-Lakes St. Lawrence
Acadian
Carolinian Zone Our backyard
Most threatened landscape
33% of Canada’s spp-at-risk
25% of Canadians live in region, 90% of Ontarians
Biodiversity hotspot
~2,300 spp. of vascular plants
Types of Forest Management
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Document Summary

Pests and pesticides: pest unwanted organism that interferes with human activities; subjective. Insecticides block reproduction, airways, nervous system: herbicides disrupt plant growth and metabolism, fungicides, rodenticides. Crop rotation, vary planting times, plant diversity, hedgerows: based on plants natural instincts . Synthetic organic compounds (eg ddt), broad- and narrow-spectrum, persistence reduction, some natural. Saves human lives malaria, bubonic plague, typhus. Increase food supplies and profits; lower costs: work faster and better than alternatives, health risk *may* be insignificant compared to benefits. 3000-6000 death/yr (epa: new pesticides are safer and used at lower rates than older pesticides. What are the true costs: genetic resistance insects and plants, kill non-target organisms, incl. natural predators. Harm wildlife: pesticide movement, human health threat; 20,000 40,000 deaths, use reduced without yield decrease. Still 6% decrease in yield loss to pests. Some based on biomimicry, part of integrated pest management (ipm: change cultivation practices (cultural, biological pest control. Plant, irrigate, fertilize, apply pest control, harvest.

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