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LECTURE 9 “CROP PROTECTION” AKA PESTICIDE USE

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LECTURE 9 “CROP PROTECTION” AKA PESTICIDE USE Powered By Docstoc
					“CROP PROTECTION” AKA PESTICIDE USE
Preparation: IPM
http://www.ipmalmanac.com/ http://www.biconet.com/reference/IPMhistory.html

AGST 3000 Agriculture, Society and the Natural World

Some Definitions
Pesticide = a substance that kills a pest (insect, weed, bacteria, nematode…)
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Herbicide = weed killer Insecticide = insect killer

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Rodenticide = rodent killer

Why are pesticides used in agriculture, society and the environment?
1. Agriculture:
a. Use of “crop protecting” agents improves yield and quality of agricultural products, consumer preferences b. Prevents the spread of diseases to crops and livestock (Pierce’s Disease) c. The use of pesticides is regulated by the E.P.A. (Environmental Protection Agency, state law and county ordinances)

Why are pesticides used in agriculture, society and the environment?...continued

2. Society & Environment:
a. Pesticides are used regularly in city parks and other recreational areas to control insect damage and weeds (ie Disneyland, ball parks, schools, etc)
b. Pesticides are used to protect humans from insect-borne diseases, mosquitoes transmit many diseases (Mosquito Abatement Programs) West Nile Virus, Malaria c. Rodenticides are used in homes, restaurants and hotels to control mice and rats which can spread disease, Junta Virus

Concerns With Pesticide Use
1. Environmental concerns a. pesticides can kill beneficial insects and plants (non selective) b. pollution – runoff of herbicides and insecticides into irrigation water and then into rivers - damages wildlife habitat c. cancer causing agents – organophosphates d. disrupt the natural ecosystem and natural biodiversity e. creates chemical resistance – insects particularly

Integrated Pest Management (IPM)
Pest management that utilizes several strategies to control insects and other pests rather than strictly relying on chemical control.
Four Components…

Integrated Pest Management (IPM) Components
1. Pest identification – important for proper pest control
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Confuse beneficial insects with harmful

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Pest that’s on the plant may not be the one causing damage
Damage may not even be caused by an insect (toxin or nutritional deficiency, weather damage etc.)

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Integrated Pest Management (IPM) Components
2. Surveying for pests – systematically check for pests and pest damage
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Pheromone traps Sweeping the field Random leaf, fruit and stem samples

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Integrated Pest Management (IPM) Components 3. Encourage Beneficial Insect/Animal Populations
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Use milder chemicals or selective sprays that don’t kill beneficial animals.

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Examples – “Barn Owl Nesting Boxes” – rodent control
Predatory wasp populations – fly control in poultry and dairy operations Natural insect enemies – lady bugs, lace wings, praying mantis, predatory mites

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Integrated Pest Management (IPM) Components

4. Control Action Guidelines –

Application of pesticides only after a certain number of pests have been found and there is a threat of economic loss.

Do's of Using Chemicals in an IPM Program

Do:
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Use chemicals only as a last resort. Identify the pest you are dealing with before purchasing and using chemicals.

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Use personal protective equipment when applying pesticides.

Don'ts of Using Chemicals in an IPM Program Don’t:
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Don't automatically use pesticides on all of your plants or your entire field. Carefully scout first, and "spot spray" in areas where pest activity is the greatest.
Don't rely on the same chemical for a long period of time. Instead, alternate chemicals with different modes of action. Don't over-apply pesticides. Always follow label directions.

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Sociology of Pesticides
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Rachel Carlson (1962) – beginning of the modern environmental movement - Silent Spring
DDT – pesticide – “Nobel Prize” in medicine
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Insect/disease control - Potent toxin Still used to control mosquitoes in 3rd world countries Malaria, Yellow Fever, Dengue Fever – spread by mosquitoes Yellow Fever – nearly prevented the colonies from being settled More soldiers were lost in WWII due to mosquitoe borne disease than in battle.

Sociology of Pesticides continued…
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Vietnam War – used defoliants to clear forests

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Post War Conditions – Refugee camps, many diseases
Modern Challenge…Disease could be used as a weapon (biological and chemical agents)

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Bubonic Plague – infected fleas & dropped them on China during WWII; killed 50,000 people
Many people think all pesticides should be banned.

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San Francisco has tried to ban all pesticides; this would include germ killers like Chlorine

Pesticide Routes of Entry
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Dermal (skin) most common
Oral Respiratory Ocular

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Pesticide Toxicological Tests
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U.S. food supply is the safest in the world
“Risk Cup” – EPA evaluate scientifically the level of risk compared to benefits. Fill the cup with all the risks an individual is exposed to during their lives.

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Politics of Pesticides
“Environmental lobbyists” are very powerful in Washington D.C.
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Natural Resource Defense Fund – contracted with 20/20 to break the story on “Alar” in apples -Alar was banned w/out scientific evidence.

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-Organo Phosphate, carbomate pesticides – research based on WWII neurotoxicity studies.

Politics of Pesticides continued…
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“Biocides” – easily manufactured & inexpensive Petroleum industry was the generator Pet pesticides – flea control, tick control Pharmaceutical industry does much of the pesticide research today, patent lasts 17 years & it takes 10 years to complete research process. How much does this cost?

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Environmental Issues with Pesticides
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Pesticides enter the environment through crop application.
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Leach into aquifer Drift from applying during wind Improper usage and disposal of containers

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Central Valley has potential problems associated with continual pesticides and chemical applications. Problem-“Bio-magnification”

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“Bio-magnification”
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Duration…Chlorodane – killed lots of bugs, 30

year half-life, very stable in soil. Mis-application of insecticide caused it to be banned.

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Accumulation…DDT – stays in the environment,
organisms pick up the molecules and it stays in the animal’s tissues…animals eat animals and it passes on…Raptor egg shell thinness

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Resistance develops – kill 99%; 1% left that are
resistant. Survivals detoxify chemicals used as pesticides low kill-rate. “Pesticide treadmill”

Some Answers to Reducing Pesticide Use
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Control populations – work within ecological principles, IPM Pest Control Advisors must use these practices, an old idea.
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Select all the techniques to control pests. Understand the ecological interactions of the pests. More is not necessarily better…follow application guidelines strictly

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California has the strictest rules and regulations concerning pesticides in the nation.

Future Challenges?
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IPM – “requires people to work smarter” dealing with biology & ecology and utilizing…
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“Environmentally Friendly” pesticides Mycotoxins – “aflatoxins” naturally occurring toxins in peanuts, mushrooms

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Organic Farming – now will be regulated by the federal government, fringe element no more. “Biotechnology” – fear of the unknown, no risk is acceptable according to anti-biotech groups.

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Future of Chemicals & Pesticides
Alternatives will be Key Issue…not a new concept!
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Beneficial insects Mechanical control Chemical controls Hedgerows – create a place for native speciesself perpetuating Cover crops that produce nitrogen…lower fertilizer use Cover crops that encourage beneficial insects... Proper irrigation for various crops…reduce runoff

Journal
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What do you think are some of the greatest threats to using pesticides..?
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In California In the US Globally

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What are some of the greatest benefits you see from using pesticides? Do you feel that we can ever live without pesticides/chemicals? Why, Why not? Do you think that we have a tendency to overreact in California and are our laws and regulations justified?

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