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Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pest Control Chapter 12.

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Presentation on theme: "Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pest Control Chapter 12."— Presentation transcript:

1 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pest Control Chapter 12

2 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Outline: Pests Pesticides  Use and Types  Benefits  Problems  Alternatives  Reducing Exposure  Regulating Use

3 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. PESTS AND PESTICIDES Biological Pests - Organisms that reduce the availability, quality, or value of resources useful to humans.  Only about 100 species of organisms cause 90% of crop damage worldwide. - Insects are most frequent pests.  Make up three-fourths of all species.  Generalists  Compete effectively against specialized endemic species.

4 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticides Pesticide - Chemical that kills (repels) pests.  Biocide - Kills wide range of organisms.  Herbicide - Kills plants.  Insecticide - Kills insects.  Fungicide - Kills fungi.  Acaricide - Kills mites, ticks, and spiders.  Nematicide - Kills nematodes  Rodenticide - Kills rodents.  Avicide - Kills birds.

5 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. PEST CONTROL HISTORY Sumerians controlled insects with sulfur 5,000 years ago. Chinese describe mercury and arsenic to control pests 2,500 years ago. People have used organic compounds and biological controls for a long time.  Romans burned fields and rotated crops to reduce crop disease.

6 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Synthetic Chemical Pesticides Modern era of pest control began in 1934 with DDT.  Cheap, stable, soluble in oil, and easily spread over a large area. - Highly toxic to insects, but relatively nontoxic to mammals.  Paul Mueller received Nobel prize in 1948 for the discovery.

7 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. PESTICIDE USES AND TYPES Pesticide use has increased dramatically since WWII.  Almost nothing in 1950 to $33 billion for 2.6 metric tons in % of pesticides are used in agriculture or food storage and shipping.  In US, household applications represent 12% of all pesticide use, but almost 23% of insecticide use.

8 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticide Types Inorganic Pesticides - Broad-spectrum, generally highly toxic, and essentially indestructible. (arsenic - copper)  Generally neurotoxins Natural Organic Pesticides (Botanicals) - Generally plant extracts. (nicotene - phenols) Fumigants - Small molecules that gasify easily and penetrate materials rapidly. (carbon tetrachloride - ethylene dibromide)

9 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticide Types Chlorinated Hydrocarbons - Fast acting and highly toxic to sensitive organisms. (DDT - mothballs)  Inhibit nerve membrane ion transport and block nerve signal transmission.  Persistent - Tend to biomagnify. Organophosphates - Extremely toxic to mammals, birds and fish. (Malathion)  Outgrowth of nerve-gas research.  Inhibit neurotransmitter enzyme.

10 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticide Types Carbamates - Similar to organophosphates. (Sevin). - Extremely toxic to bees. Biological Controls  Microbial agents  Bacteria  Parasitic Wasps

11 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. PESTICIDE BENEFITS Disease Control  Many insects serve as disease vectors. - Malaria, Yellow Fever Crop Protection  Using pesticides, pre-harvest losses to diseases and pests are at 30%, with post- harvest losses at an additional 20-30%.  In general, farmers save an average of $3- $5 for every $1 spent on pesticides.

12 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. PESTICIDE PROBLEMS Non-Target Species  Up to 90% of pesticides never reach intended target. Pesticide Resistance  Resistant members of a population survive pesticide treatment and produce more resistant offspring. - Pest Resurgence

13 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticide Resistance UN reports at least 500 insect pest species and 250 weeds and plant pathogens have developed chemical resistance.  Farmers must continually change dosages or chemicals to fight resistant pests. - Increasingly, pests are being found to be resistant to chemicals they have not been exposed to.  Genetically-engineered crops likely to exacerbate the problem.

14 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Pesticide Resistance

15 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Creation of New Pests Broadcast spraying is also likely to kill beneficial predators.  Under normal conditions many herbivorous pests are controlled by natural predators. With advent of chemical pest controls, farmers have tended to abandon traditional methods of pest/pathogen control.  Mixed crops and rotation regimes.

16 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Environmental Persistence and Mobility Because chlorinated hydrocarbons (DDT) are so persistent, they tend to show up far from the point of dispersal.  Stored in fat bodies, and thus tend to bioaccumulate. - High levels detected in upper levels of food chain.  DDT banned from US for over twenty years, but high levels still detected in some areas.

17 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Environmental Persistence and Mobility Many persistent organic pollutants were banned globally in  Use was banned or restricted in developing countries for years, but between 1994 and 1996, the US shipped more than 100,000 tons of DDT and POP’s annually. - Many returned to US in agricultural products and migrating wildlife.

18 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Human Health Problems WHO estimates between 3.5 and 5.0 million people suffer acute pesticide poisoning, and 20,000 die, each year.  At least two-thirds resulting from occupational hazards in developing countries.  Long-term health effects difficult to conclusively document. - PCB’s have been linked to learning deficiencies in children.  Intake during mother’s pregnancy.

19 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. ALTERNATIVES TO PESTICIDE USE Behavioral Changes  Crop Rotation  Mechanical Cultivation  Flooding Fields  Habitat Diversification  Growing in Pest-Free Zones  Adjusting Planting Times  Plant Mixed Polycultures

20 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Alternatives to Pesticides Biological Controls  Predatory / Herbivorous Insects  Genetics and Bioengineering  Hormones  Sex Attractants

21 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Integrated Pest Management Flexible, ecologically-based strategy that uses a combination of techniques applied at specific times aimed at specific pests.  Tries to minimize use of chemical controls and avoids broad spectrum controls.  Employs economic thresholds to determine the point at which potential economic damage justifies pest control expenditures.

22 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. REDUCING PESTICIDE EXPOSURE Less than 10% of active pesticide ingredients have been subjected to a full battery of chronic health-effect tests.  Of the 321 pesticides screened, EPA reports 146 are probable human carcinogens. - Since 1972, only 40 pesticides have been banned.

23 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Regulating Pesticides Environmental Protection Agency (EPA), Food and Drug Administration (FDA) and Department of Agriculture (USDA) all share federal responsibility for regulating pesticides used in food production in the US.  EPA regulates sale and use, and sets tolerance levels.  FDA and USDA enforce pesticide use and tolerance levels set by EPA.

24 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Regulating Pesticides 1999, EPA banned use of methyl parathion on all fruit and many vegetables, and limited the quantity of azinphos methyl that can be used on foods common in children’s diets.  Studies show children are more susceptible than adults to toxic pesticides because they are still developing and have less natural protection.

25 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed. Summary: Pests Pesticides  Use and Types  Benefits  Problems  Alternatives  Reducing Exposure  Regulating Use

26 Cunningham - Cunningham - Saigo: Environmental Science 7 th Ed.


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