1. Protecting Food Resources:
Pesticides and Pest Control

2. Pesticides: Types and Uses
What is a Pest?
A pest is any species that competes with us for food, invades lawns and gardens, destroys wood in houses, spreads disease, or is simply a nuisance
Most of the time nature takes care of the pests through natural enemies (predators, parasites, and disease organisms)

3. So what’s a Pesticide?
Pesticides (also known as biocides) are chemicals that are to kill organisms we consider undesirable
ex. – insecticides, herbicides, fungicides, nematocides, and rodenticides

4. Above: Worker prepares his vehicle for a day of pesticide spraying

5. Coevolution
For almost 225 million years, plants have been producing chemicals to ward off or poison herbivores that feed on them…
But, through what is known as coevolution, the predators overcome various plant defenses by natural selection and the plants must develop new defenses

6. First Attempts at Pesticides
Sulfur (early 500 BC)
Toxic compounds of arsenic, lead, and mercury (1400’s)
Abandoned in late 1920’s when the increasing number of human poisonings increased
Nicotine Sulfate (1600’s)
Pyrethrum and Rotenone (mid-1800’s)

7. Paul Mueller and the Second Generation
In 1939 Paul Mueller discovered that DDT, a chemical known since 1874, was in fact a potent insecticide. DDT became the first pesticide of the so-called Second Generation Pesticides. Mueller went on to win the Nobel Prize in 1948 for his discovery.

8. Pesticides Today
Chemists have been developing hundreds of synthetic organic chemicals for use as pesticides
Worldwide about 2.3 million metric tons of pesticides are used yearly
1 lb for each person on earth
75% in developed countries (Latin America, Asia and Africa on the rise)
1996 world sales = $30 billion($11 billion: US)

9. Spray those fields

10. Here in the US
About 630 different biologically active (pest killing) ingredients and about 1,820 inert (inactive) ingredients are mixed to make some 25,000 different pesticide products in the United States

11. Pesticide Distribution in US
Cultivation of two crops
Cotton (55%)
Corn (35%)
Used about 90% of the insecticides and 80% of the herbicides applied to crops in the United States in 1995

12. Example of Solid Pesticides

13. More Distribution
25% of the pesticide use in the United States is for ridding houses, gardens, lawns, parks, playing fields, swimming pools, and golf courses of unwanted pests
Average lawn in US = 10x’s more pesticides per hectare than US cropland
Each year = 250,000 residents become ill

14. Some Quick Facts Broad-Spectrum agents : toxic to many species
Selective or Narrow spectrum agents : effective against a narrowly defined group of organisms
Pesticides vary in persistence (length of time they remain deadly in environment)

15. The Pros
Pesticides save human lives: has prevented premature births due to malaria, bubonic plague, typhus, sleeping sickness (all carried by pests)
Pesticides increase food supplies and lower food costs: 55% of crop lost before harvest due to pests
Pesticides increase profits for farmers: every $1 spent on pesticides yields worth approximately $4 (although dropped to $2 if harmful effects)

16. Farmers in all countries have tried pesticides to save there crops

17. More Pros
Pesticides work faster and better than alternatives: Pesticides can control pests quickly and at a reasonable cost. Long shelf life and easily shipped and applied
Health risks insignificant when compared to their benefits
Safer more effective pesticides are being developed
New pesticides are being used in less rates per unit when compared to older products

18. Ultimate Goal of Pesticides
Kill only the target pest
Harm no other species
Disappear or break down into something harmless after doing its job
Not cause genetic resistance in target
Be cheaper than doing nothing

19. The Cons
Genetic Resistance: pest organisms develop resistance to the pesticide after a short period of being exposed to it
Broad-Spectrum insecticides kill natural predators and parasites that may have been maintaining the population of a pest species at a reasonable level
Ex. Wolf spiders, wasps, predatory beetles…

20. Cons continued…
Because natural predators can be wiped out; this may unleash new pests whose populations the predators had previously held in check

21. In Our Water
Testing in rivers and water reveal that pesticides have strayed away from there targets and found there way into the waters

22. Pesticide Treadmill
As pests become resistant to the pesticides, sales reps for the pesticide recommend larger doses or more frequent application
As a result farmers end up on a pesticide treadmill where they end up paying more and more for a pest control program that often becomes less and less effective

23. Example of Pesticide Treadmill
In Central America, cotton growers increased the frequency of insecticide applications from 10 to 40 times per growing season. Still, declining yields and falling profits forced many of the farmers into bankruptcy

24. Where does it all go?
Only about 2% of the sprayed insecticide by air reaches target pests
Less than 5% of herbicides applied reach target weed
Pesticides that don’t reach there target end up in the air, surface water, groundwater, bottom sediments, food and other nontarget organisms

25. Continued
Still, pesticide waste can be reduced by using recirculating sprayers, covering spray booms, and using rope-wick applicators

26. DDT
Banned in 1972 by US
1980 high levels in peregrine falcon and the osprey
EPA found DDT in 99% of the freshwater fish it tested
DDT drifts from other countries still using it

27. Checking for pesticide residue in food

28. Regulation in the US All commercial pesticides must be approved by EPA
EPA reviews each pesticide
EPA sets tolerance levels : amount of toxic pesticide residue that can legally remain on crop
No longer has to test on birds and fish
55 active pesticides banned in US, but may be used and shipped elsewhere

29. More Regulations
National Academy of Sciences says that the federal laws are not adequate
98% of potential risk of cancer would be eliminated if pesticide residue on food eliminated by government
Approximately $1 Billion spent on regulating pesticides each year

30. 1996 Food Quality Protection Act
Requires food to have only reasonable levels of pesticide tolerance
It requires manufacturers to demonstrate that the active ingredients in there products are safe for infants and children
Requires EPA to consider exposure to more than one pesticide when setting pesticide tolerance levels
EPA develops program to screen ingredients

31. From Above
Just one of the many ways that pesticides are being applied are through aerial drops of the chemicals

32. Other Solutions Crop rotations Planting times can be adjusted
Plowing at night (reduces weeds)
Plant where major pests do not exist
Switch away from monoculture to intercropping, agroforestry, and polyculture

33. More Solutions
Plants and animals that are genetically resistant to certain pest insects, fungi and diseases can be developed
- downside: costly
Biological control: predators and pathogens
300 biological pest control successful in China and Cuba
Biological Control: non-toxic to humans
Downside: timely

34. Pesticides are plentiful as seen here and it comes in many different forms

35. Even more Solutions… Plant toxins
Bt toxin used to kill thousands of strain of common soil bacterium
Insect Birth Control (sterile male approach)
Aqua heat: spray boiling water on crops

36. Yes… more solutions
Some crops can be exposed to gamma rays after harvest
Extends shelf life
Critics say irradiating food destroys vitamins and other nutrients
Increases death from botulism poisoning
Picowaved stickers on food that has been

37. IPM Integrated Pest Management
Goal is reduction of crop damage t an economically tolerable level
Carefully monitor damage levels of pests
When reached, farmers first use biological methods
Small amounts of insecticides are used as a last resort

38. Pesticides in Politics
Pesticides have been a big issue with environmentally safe activists. It is a big topic the EPA has to deal with