please read carefully ..
Biology 140
Instructor: Dr. Franklin Quarcoo
Office Location: 103 Morrison-Mayberry Hall
Phone: 727-8792
Office Hours: MWF 3.00 – 5.00 pm
Email: fquarcoo1@tuskegee.edu
- Pests
- Pesticides
- Benefits
- Problems
- Categories
- Chemical types
- Regulation of Pesticides
- Alternatives to Pesticides
- Reducing Pesticide Exposure
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- Everything we study in this segment of the course has a direct impact on environmental quality, QUALITY OF LIFE and sustainability. That means it affects you, your family, friends and all animal and plant life forms.
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- What is a pest?
- There are several definitions …
- Any organism that competes with man for resources which include crops, livestock, forests, health, recreation, etc.
- Organisms that reduce the availability, quality or value of a human resource; transmit disease; constitute a nuisance
- Anthropocentric designation
- Examples of pest groups:
- Agricultural
- Medical
- Veterinary
- Urban
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- Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any insect, rodents, nematodes, fungi, or weeds, or any other forms of life declared to be pests; and any substance or mixture intended for use as a plant regulator, defoliant, or desiccant.
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
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- By how they affect our lives:
- Agricultural.
- Medical.
- Veterinary.
- Urban.
- By taxonomic category:
- Insects -- damage crops, transmit disease, nuisance.
- Weeds -- compete with crops, unsightly in lawns.
- Fungi -- damage crops.
- Rodents -- damage crops, urban nuisance.
- Mites -- transmit plant diseases.
- Nematodes -- soil roundworms that damage crops..
- Pesticides: chemicals that kill pests.
- Most commonly used method.
- Cultivation practices.
- Biological control -- natural enemies.
- Biotechnology.
- Integrated Pest Management (IPM).
- Since 1950, pesticide use has increased 50-fold.
- In U.S. 650 pest-killing chemicals used to make 25,000 pesticide products.
- In U.S. 25% of pesticides are used in homes, gardens, lawns, parks, swimming pools, golf courses.
- In U.S. lawns receive 10 times the pesticide dose that cropland receives..
- Disease control
- Crop protection
- Economics
- Others
- Malaria
- Spread by mosquitoes.
- 500 million suffering at any time.
- 3 million die per year.
- Other diseases spread by mosquitoes: yellow fever, west Nile virus.
- Other insects that spread disease: sleeping sickness (tsetse fly), bubonic plague (fleas), river blindness (flies), elephantiasis (flies).
- Pesticide use has prevented from 7 to 50 million deaths from malaria and other insect-transmitted diseases in 50 years (1950-2000).
- 90% of pesticides world-wide are used in agriculture or in food storage and shipping.
- In U.S. agriculture most pesticides used on corn and cotton (90% of insecticides, 80% of herbicides).
- Plant diseases, insects, birds and competition from weeds reduces crop yield worldwide by at least 1/3.
- Post-harvest losses to rodents, insects and fungi – another 20-30% loss.
- Every dollar spent on pesticides earns a farmer $ 3-5 more from increased yield.
- Greater food production.
- Lower food prices.
- Faster and greater pest reductions than alternatives.
- Low health risks if used properly.
- EPA worst-case scenario – pesticides in food cause 0.5-1.0% of cancer deaths in U.S.
- New pesticides are safer and more effective than older ones.
- Better than doing nothing.
ICA
- Which of the following is true in the U.S.?
- (a) 10 times as much pesticide product is used on lawns as on cropland.
- (b) 10 times as much pesticide per acre is used on lawns as on cropland.
- (c) 10 times more acres of lawn than acres of cropland are treated with pesticide.
- (d) Lawns are treated with pesticide 10 times more often than is cropland.
- Which of the following is true in the U.S.?
- (a) 10 times as much pesticide product is used on lawns as on cropland.
- (b) 10 times as much pesticide per acre is used on lawns as on cropland.
- (c) 10 times more acres of lawn than acres of cropland are treated with pesticide.
- (d) Lawns are treated with pesticide 10 times more often than is cropland.
- Which of the following diseases is transmitted by the tsetse fly?
- (a) Bubonic plague
- (b) Malaria
- (c) Sleeping sickness
- (d) West Nile virus
- (e) Both b and d.
- Which of the following diseases is transmitted by the tsetse fly?
- (a) Bubonic plague
- (b) Malaria
- (c) Sleeping sickness
- (d) West Nile virus
- (e) Both b and d.
- 90% of pesticides never reach intended targets.
- Unintentional poisoning of beneficial species.
- 20% of all honeybee colonies destroyed each year by pesticides.
- Atlantic salmon declined 77% -- linked to spraying of pesticides on Canadian forests.
- Pesticides don’t kill 100% – a few are resistant.
- Population regrows with pest-resistant indivduals.
- Pest becomes resistant to pesticide.
- By 1990, 500 insect pests and 250 weeds and plant pathogens were resistance to pesticides.
- Larger doses required ---> more resistance ---> even larger doses ---> even more resistance = pesticide treadmill..
- From 1940s to 1990s:
- Pesticide use increased 33-fold (33 times as much).
- But crop losses to insects, weeds and diseases did not change.
- Amount of pesticide required to protect 60,000 bushels of corn:
- 1946 -- 1 kg
- 1971 -- 64 kg..
- Many potential pests are NOT pests because they are controlled by their natural enemies (predators).
- Pesticides often kill the predators, then potential pests become actual pests.
- 100 of top 300 pests in U.S. became major pests after wide-spread use of pesticides..
Low numbers of pests --
controlled by predators
High numbers of pests --
predators reduced
by pesticide
- Before 1949 yields = 500 kg/ha.
- 1949: began spraying with DDT.
- 1952: yields = 750 kg/ha.
- 1952-3: Boll weevils became resistant; populations rebounded.
- Heliothis worms became new pest on cotton.
- DDT had killed the wasps that controlled the Heliothis worms.
- 1955: Yields down to 330 kg/ha..
ICA
- Pests become resistant to pesticides because:
- (a) Individual pests build up a immunity to the pesticide with repeated applications.
- (b) Some pests with natural resistance to the pesticide survive and repopulate the area.
- (c) The pesticides break down with age and become less effective.
- (d) The pesticides kill the natural enemies of the pests.
- Pests become resistant to pesticides because:
- (a) Individual pests build up a immunity to the pesticide with repeated applications.
- (b) Some pests with natural resistance to the pesticide survive and repopulate the area.
- (c) The pesticides break down with age and become less effective.
- (d) The pesticides kill the natural enemies of the pests.
- Most insects that have the potential to do major damage to our crops have never become major pests because:
- (a) They do not live long enough to become pests.
- (b) They have been controlled by pesticides.
- (c) They have been controlled by their predators and diseases.
- (d) They reproduce too slowly to become pests.
- (e) both a and d.
- Most insects that have the potential to do major damage to our crops have never become major pests because:
- (a) They do not live long enough to become pests.
- (b) They have been controlled by pesticides.
- (c) They have been controlled by their predators and diseases.
- (d) They reproduce too slowly to become pests.
- (e) both a and d.
Assignment:
- What is Hormoligosis
- Acceptable Daily Intake (ADI)
- No observable Adverse Effects Level (NOAEL)