Pest Management Chapter 23 APES Aaron Willey Spring 2013

Essential Questions Types and characteristics of pesticides Pros and cons of using pesticides Pesticide regulation in the US Alternatives to chemical pesticides

Your teacher’s obsession with spiders

Nature’s PESTicide

What is a Pest anyway? A pest is any species that… – Competes with humans for food – Invades lawns and gardens – Destroys wood in houses – Spreads disease – Are a nuisance Worldwide, only about 100 species of plants (weeds), animals (insects), fungi, and microbes cause about 90% of the damage

Polyculture Monoculture Natural “checks and balances” – Natural enemies (predators, parasites, and disease organisms) control most pest species Monoculture crops – Now WE are forced to control pests nature once took care of (for free)

Pesticides (aka Biocides) Chemicals used to control pests – Insecticides (insects) – Herbicides (plants) – Fungicides (fungi) – Rodenticides (rats and mice)

Coevolution

First-Generation Pesticides Prior to 1940’s Inorganic compounds – As, Hg, Pb Organic compounds – Nicotine sulfate (tobacco) – Pyrethrum (chrysanthemum) – Rotenone (tropical forest legumes)

Second-Generation Pesticides Synthetic organic compounds Ranges from broad to narrow- spectrum agents and persistence levels

DDT 1939 Paul Müller – Entomologist – Nobel prize

Life after DDT Since 1970, chemists have returned to natural chemicals (neem tree) to produce pesticides 2003 natural pesticide in Knapweed discovered

Pesticide use today Pesticide use on crops have leveled off since 1980 Use on homes, lawns, parks, golf courses, etc have risen 50-fold since 1950 – Most of these are 10 times as toxic

Table 23-1 Major Types of Pesticides Know: – Major classes – Broad or narrow-spectrum – Degree of persistence – Example of each – Does it undergo bioaccumulation – Difference between contact and systemic herbicides (See p. 520)

Concept Check Briefly describe the history of the development of pesticides

The Good…. 1.They save human lives DDT and other chlorinated hydrocarbon and organophosphate insecticides have prevented many deaths – Malaria (mosquitoes) – Bubonic plague (rat fleas) – Typhus (body lice, fleas)

The Good They increase food supplies 55% of the world’s potential human food supply is lost to pests (37% of US)

The Good…. 3. They increase profits for farmers* 4. They work faster and better than alternatives 5. When used properly, their health risks are very low compared to their benefits* *Pesticide companies and American Council on Science and Health (ACSH)

Encouraging facts about Pesticides Newer pesticides are safer and more effective Many new pesticides are used at lower rates Genetically engineered crops could reduce the need for pesticides

What would an IDEAL pesticide look like? 1.Affect only target organism 2.Not cause genetic resistance 3.Break down/disappear in environment 4.More cost effective than doing nothing

The Bad…. 1.Insects can rapidly become genetically resistant to widely used pesticides Main problem with synthetic pesticides-It accelerates genetic resistance – Since 1945, several hundred species have become resistant – Reemergence of diseases (malaria) – Pesticide treadmill

The Bad…. 2. Pesticides kill natural enemies of pests and create new pests Of the 300 most destructive insect pests in the US…… …..100 were once minor pests

The Bad…. 3. Pesticides do NOT stay put!

The Bad…. 4. Some harm wildlife (bees, birds, fish endangered species) 20% loss of honeybee colonies every year = 200 million cost to farmers

The Bad…. 5. Harm to humans Agricultural workers – 3 million/yr (developing countries) – 300,000/yr US 4,000-20,000 cancer cases/yr Childhood leukemia, Parkinson’s, immune disorders, prostate cancer, breast cancer, behavioral disorders

Do they even make a difference? David Pimentel, insect ecologist – In the 1940’s, 31% of US crops lost to pests So pesticide use increased 33-fold. – Today about 37% of US crops lost to pests

Do they even make a difference? David Pimentel, insect ecologist – Estimated environmental, health, and social costs of pesticides has been estimated up to $ billion/yr

Do they even make a difference? David Pimentel, insect ecologist – Alternative practices could cut the pesticide use in HALF on 40 major US crops WITHOUT reducing yields

All My Pesticide Regulations Organophosphates Persistent Organic Pollutants (POPs) “Dirty Dozen” President Kennedy 56 Active ingredients Tolerance level 43 out of 165 Pesticide Industry Environmentalists Federal Insecticide, fungicide and Rodenticide Act (FIFRA) Environmental Protection Agency DDT Food Quality Protection Act (FQPA) Missouri children National Academy of Science India and Africa Rachel Carson’s Silent Spring

What should be the primary goal of pest control efforts? Reduce crop damage to an economically tolerable level – Economic threshold: the point at which the economic losses outweigh the cost of applying pesticide How do you determine when this threshold has been met? – Insurance spraying – Pest-loss insurance – Cosmetic spraying

Alternative Methods 1.Cultivation practices – Crop rotation, switch planting seasons, polyculture, etc. – Grass height, plant selection

Alternative Methods 2. GMO – Pest and disease- resistant – Controversial

Alternative Methods 3. Biological pest control – Introducing natural enemies – What pros and cons can you think of?

Alternative Methods 4. Insect birth control – Sterilization from radiation and chemicals – Screwworm fly

Alternative Methods 5. Hormones – Pheromones – Interrupt life cycle

Alternative Methods 6. Hot water – Cotton, alfalfa, potato, citrus 7. Gamma radiation - Trace chemicals? - Long-term effects?

When to go organic Nectarines – 97.3% of nectarines sampled were found to contain pesticides. Celery – 94.5% Pears – 94.4% Peaches – 93.7% Apples – 91% Cherries – 91% Strawberries – 90% Imported Grapes – 86% Spinach – 83.4% Potatoes – 79.3% Bell Peppers – 68% Red Raspberries – 59%