Transcript pesticides
PESTICIDES: TYPES & USES Characteristics of Pests: 1) Competes with us for food 2) Invades lawns & gardens 3) Spreads Disease 4) Destroys wood in homes Major types of pesticides: Insecticides – used to kill insects Herbicides – weed killers Fungicides – used to kill molds, rusts Nematocides – round worm killers Rodenticides – rat & mouse killers Major Types of PESTICIDES Insecticides Chlorinated Hydrocarbons – DDT, aldrin, dieldrin, chlordane Organophosphates - Malathion Herbicides Contact chemicals - atrazine Systemic chemicals – glyphosate (round-up) • Pesticide use has increased dramatically since WWII. – Almost nothing in 1950 to $33 billion for 2.6 metric tons in 1999. • 90% 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. 84% of US homes use pesticide products – bait boxes, fungicides, roach/ant spray, weed killers, wasp/bee spray, flea prevention PESTICIDE USES AND TYPES First Generation Pesticide Control: • Sumerians controlled insects with sulfur 5,000 years ago. • Chinese used mercury and arsenic to control pests 2,500 years ago. • People have used organic compounds and biological controls for a long time. – Biological controls – rotenone (made from roots of tropical plants) – Physical controls - Romans burned fields and rotated crops to reduce crop disease. Second Generation Pesticide Control: • Modern era of pest control began in 1939 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. PESTICIDE BENEFITS 1) Saves Lives – Malaria - mosquitoes (DDT) Plague – rat fleas Typhus – body lice & fleas Over 70% of pesticides are used in the developed countries – AGRIBUSINESS Sleeping Sickness – Tsetse Fly 2) Increased Food Supply 3) Lower Food Costs 4) Work Faster than alternatives – such as biological controls; physical controls Pests destroy ~40% of food crops per year!! Costs 65 million dollars a year! Most common used pesticides: Insecticides; Herbicides; Fungicides Whose Using All Those Pesticides Anyway? WE ALL ARE! Pink Bollworm – southwest Gypsy moth caterpillar – northeast Grasshoppers – Midwest/West Red Mites – Northeast; Northwest Boll Weevil Southeast IDEAL PESTICIDES would… o Kills only the target pest!! o Harms no other species in ecosystem o Disappears or breaks down into something non toxic o Does not promote genetic resistance in pests o Is more cost-effective (cheap) o Not synergistic with other pollutants Rapid Evolution is occurring in pests because of pesticide use! Pesticide Treadmill & Genetic Treadmill – farmers using larger doses and more frequent applications b/c of decreasing effectiveness of pesticides and GMO’s . Secondary Pest Outbreaks – occurs due to broad spectrum pesticides killing natural predators. Allows organisms whose populations would be kept in check to become “new pests”. PESTICIDE PROBLEMS Endocrine disruptors (DDT (estrogen mimic), PCBs, Atrazine, Bisphenol A) & are carcinogens Wildlife – unusual mating patterns, mothers abandoning nests, gamete formation - mutations Humans – increase cancers (prostate, breast), increase in miscarriage, increase in male infertility They can be persistent and biomagnify in the ecosystem (DDT; PCBs) Neurological Damage – PCBs , Dioxins, mercury Surface Water Runoff of pesticides – killing millions of fish Direct contact of farmers resulting in deaths – organophosphates (malathion) Broad Spectrum Pesticides – killing useful insects - honeybee After conducting the tests, they found that an average pesticide residue of 11.85 ppb was found in every sample. The samples had a cocktail of three to six pesticides contained. Photo was run in the India Daily Magazine Accoding to the India Daily Magazine: The Center for Science and Environment, CSE, tested fifty-seven samples of soft drinks from eleven popular brands of multinational cola companies in its own laboratory. The samples were collected from the twenty-five bottling plants across twelve cities in India.