please read carefully ..
Biology 140 Instructor: Dr. Franklin Quarcoo
Office Location: 115 Henderson Hall Phone: 727-8792
Office Hours: MWF 3.00 – 5.00 pm Email: quarcoof@mytu.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 his 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 ú Anthropocentric designation
¡ Examples of pest groups: ú Agricultural ú Medical ú Veterinary ú 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)
¨ 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 Effects Level (NOEL)