Chapter 10: Pest Control

1. Chapter 10: Pest Control Rex Messing

2. Pests and Pesticides • A pest is something or someone that annoys us, detracts from some resource that we value, or interferes with a pursuit that we enjoy • Biological pest- organisms that reduce the availability, quality, or value of resource useful to humans • Based partly on perspective • A mosquito annoys us but is a good food source for bats and birds • Dandelions are considered weeds in the western hemisphere, but in some countries they are grown as a crop • 100 plants, animals, fungi, and microbes cause 90% of all crop damage world wide • Insects are considered to be the most frequent pest because they are ｾ of all species on earth • Most tend to be generalist that reproduce rapidly and migrate quickly

3. Pesticides • Pesticide- is a chemical that kills pests • Not always toxic, some prevent development • Other approaches to pest control are burning crop residues or draining wetlands to eliminate breeding sites • Biocide- a broad-spectrum pesticide that kills a wide range of living organisms • Herbicides- Kill plants • Insecticides- Kill insects • Fungicides- Kill fungi

4. Ancient Approaches • Every culture has been known to use salt, smoke, or insect repelling plants to keep away pests or preserve foods • Sumerians used sulfur 5000 years ago • Chinese used mercury and arsenic 2500 years ago • Alcohol from fermentation to prevent growth of organisms that would spoil food

5. Modern Pesticides • DDT • 1939 Swiss chemist Paul Muller created dichloro-diphenyl-trichloroethane • Very lethal for wide range of insects • Began to have bad affects on wildlife Rachel Carson’s Silent Spring • EPA estimates that 5.3 billion pounds of pesticides are used per year • About half is chlorine and hypochlorites for water purification • Next largest category is conventional pesticides such as insecticides, herbicides, and fungicides • 80% of all conventional pesticides are used for food storage of shipping • According to CropLife America, 90 million ha of crops are treated with herbicides a year

6. Percentage of Pesticides used in the United States

7. Types of Pesticides • Defined by chemical culture • Inorganic pesticide- include compounds of arsenic, sulfur, copper, lead, and mercury • Generally highly toxic and basically last forever • Natural organic Pesticides- or “Botanicals,” generally are extracted from plants • Ex. Nicotine, Rotenone, Turpentine • Fumigants- small molecules that gasify easily and penetrate rapidly into a variety of materials • Ex. carbon tetrachloride, carbon disulfide, or ethylene dichloride • Chlorinated hydrocarbons-organochlorines that are synthetic organic insecticide that inhibit nerve membrane ion transport and block nerve signal transmission • Ex. DDT, chlordane, aldrin, dieldrin, toxaphene • Organophosphates- they inhibit cholinesterase, an enzyme essential for removing excess neurotransmitter from synapse in the peripheral nervous system • Ex. parathion, malathion, dichlorvos, chlorphyrifose • Carbamates- are extremely toxic to bees, but lack environmental persistence • Ex. Urethanes, mirex • Micro Agents- are living organisms or toxins derived from them used in place of pesticides

8. Benefits of Pesticides • Controlling insect borne diseases: • insects and ticks numerous pathogens and parasites • malaria: DDT saved 50 million over 50 years • yellow fever, Encephalitis, West Nile, sleeping sickness • Without pesticides, we may lose two-thirds of conventional crops • estimated that farmers save 3-5 dollars for for every $1 spent on pesticides • CropLife America estimates that $21 billion dollars lost in food production • Reduced up to 67% • 70 million additional laborers to remove weeds by hand

9. Pesticide Problems • Often poison nontarget species: • Estimated that 90% of pesticides used never reach intended target • Pest Resurgence- the idea of creating a population of pesticide resistant offspring through breeding • 1000 insect species and 550 weeds have developed chemical resistance • Pesticicde Treadmill- constantly try newer and more toxic chemicals in an attempt to stay ahead of the pests • Tough because some genetically resistant genes are passed between species before a species is ever exposed to a pesticide • Ex. 50 to 60 types of malaria carrying mosquito species are resistant to DDT because of widespread usage

10. Problems Cont. • Misusage can create new pests: • Broad spectrum pesticides are eliminating the lower number of beneficial predators • Ex. Wasps, ladybugs, praying mantises • Relying on pesticides overtakes traditional farming methods such as mixed crops, or rotation regimes • Effective pesticides are stable, highly soluble, and highly toxic, making them the biggest nightmare • Traces of pesticides are found many years later in areas that were not treated with pesticides • Persistent Organic Pollutants (POPs)- are so long-lasting and so dangerous that they have been banned in 127 countries • Dirty dozen: aldrin, clordane, dieldrin, DDT, endrin, hexachlorobenzene, neptachlor, mirex, toaphene, polychlorinated biphenyls (PCBs), dioxins, and furans

11. Human Health Affects • Two categories: • Acute effects such poisoning and illnesses caused by relatively high doses and accidental exposure • Chronic effects suspected to include cancer, birth defects, immunological problems and other chronic degenerative diseases • 25 million suffer pesticide poisoning and 20 thousand die each year from pesticide poisoning related diseases • Two thirds of the results came from occupational exposure through usage without proper warning or protective clothing • Hard to document specific cases for chronic affects of pesticide exposure but evidence shows problems • Lower IQs, trouble focusing • Ex. California children 3 times as likely to have acute lymphocytic leukemia when living in a once fumigated home

12. Alternatives to Current Pesticide Uses • Improved management programs can cut pesticide use 50 to 90% without lowering crop production

13. Different Solutions • Crop rotation can keep pest populations from building up • Mechanical cultivation can substitute herbicides • Flooding fields before planting or burning crop residues and replanting with a cover crop can suppress both weed and insect pests • Habitat diversification prevents soil erosion and provides perch areas for nesting birds that eat pests • Planting at different times and at different locations to avoid pests is another method • Monoculture fields • Tillage is effective at certain times of the year

14. Organisms That can Help with Pest Control • Predators can control many pest cheaper and safer than broad-spectrum synthetic chemicals • Naturally occurring bacterium that kills larvae but is harmless to mammals • Ducks, chickens, geese, and other large species are used to rid fields of insects and pests • Herbivorous insects have been used for weed control • Some plants produce natural pesticides or repellents • Genetics and bioengineering (GMOs) can help the fight against pests • Use hormones that upset development or sex attractants to bait traps containing toxic pesticides

15. Integrated Pest Management • Integrated Pest Management (IPM)- is a flexible, ecologically based pest control strategy that is applied at specific times and aimed at specific crops and pests • Often uses mechanical cultivation and techniques such as vacuuming bugs off crops as an alternative to chemical application • Tries to use minimum amount and avoids broad-spectrum pesticides • Encourages plant defenses and diversity of beneficial organisms • Trap crops • Economic Thresholds- the point at which potential economic damage justifies pest control expenditures, and precise time, type, and method of pesticide application is critical in IPM • Considered widely affective in the US and world wide • Exposure • 2.4 million metric tons of pesticides used in US every year contain 600 active ingredients • 1200 presumably inactive carriers, solvents, preservatives, and other ingredients in about 25000 commercial products • Less that 10% of active pesticide ingredients have received full tests • Of 321 pesticides screened so far, 146 are probably human carcinogens • 40 have been banned since 1972

16. Who Regulates Pesticides? • 3 federal agencies: • EPA: Environmental Protection Agency • Regulates sale and use of pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) • EPA determines which pesticides are the biggest risk • Also sets levels of pesticides that may remain in in foods • FDA: the Food and Drug Administration • Enforce tolerance levels set by EPA • Can seize and destroy any food shipment found to violate EPA limits • USDA: the Department of Agriculture • Enforce tolerance levels set by EPA • Can seize and destroy any food shipment found to violate EPA limits

17. 12 Most Contaminated Foods • Strawberries • Bell Peppers • Spinach • Cherries (US) • Peaches • Cantaloupe (Mexican) • Celery • Apples • Apricots • Green Beans • Grapes (Chilean) • Cucumbers

18. Is Organic the Answer? • Many farmers and buyers have gone to organic to avoid pesticide consumption • More eco-friendly and leaves soil healthier • Yields in organic plots are 20 percent less than conventional fields • Net returns for organic farming was higher than conventional farming • 56% less energy use on organic field • Pest-eating predators found to be in greater abundance in organic fields • 400 times less erosion than conventional farming • Less than 1% devoted to organic growing in US • More popular in Europe with 18% in Liechtenstein and 11% in Sweden

19. Organics Cont. • “100% organic” must be produced without hormones, antibiotics, pesticides, synthetic fertilizers, or genetic modifications • “Organic” means that at least 95% of the ingredients must be organic • “Made with organic ingredients” must contain at least 70% organic ingredients • Organic animals must be raised on organic feed, given access to the outdoors, given no steroidal growth hormones, and treated with antibiotics only to treat diseases

20. The Skeptics • People doubt organic growers can produce enough food within these definitions to feed everyone • They need chemical pesticides and large scale, chemical intensive farming to provide enough food for the portrayed world population • It is thought that we can only produce enough food to feed 2 to 3 billion people without pesticides or synthetic fertilizers • Potential health risks go along with eating organic food only • “Bacteria and parasites are also all-natural”

21. Protect Yourself • Wash and scrub all fruits an vegetables • Peel fruits and vegetables when possible • Store food carefully • Cook or bake goods that you suspect to have been treated with pesticides • Trim fat from meat, chicken and fish • Don’t pick and eat berries or other wild fruits that grow on roadsides • Grow your own fruits and vegetables • Ask for organically grown food or shop at a farmer’s market