Pesticides and Pest Control. Mrs. Cook Environmental Science. Objectives:. Define Pesticides Discuss the Pro’s and Con’s of Pesticide use Understanding of Regulations Alternatives. Types and Uses. A Pest is any species that - invades lawns and gardens - destroys wood in houses
A Pest is any species that
- invades lawns and gardens
- destroys wood in houses
- competes with us for food
- spreads disease
- simply a nuisance
-Nicotine- from tobacco leaves
-Pyrethrum- from chrysanthemum flowers
-Rotenone- from roots of various tropical forest legume
-Chemicals borrowed from plants that had been defending themselves from insects
In the 1950's The World Health Organization (WHO) financed and supported the first ever team of over 14,000 parachuting cats into Borneo!
In the 1950's, the Dayak people of Borneo tragically suffered an outbreak of malaria, spread by mosquitoes. The World Health Organization (WHO), without thinking through all the consequences, sprayed the area with DDT to kill the mosquitoes. The mosquitoes died, malaria lessened and the people of Borneo were happy.
But then grass roofs on the villagers houses started to collapse. It appeared that a parasitic wasp had previously been keeping a thatch-eating caterpillar under control and the DDT killed the wasps, meaning the caterpillars were free to eat as much as they wanted!
WHO initiated Operation Cat Drop and the cats started parachuting. The people of Borneo gained new feline friends, the rat population declined and the people of Borneo were happy once more. The End.
As Rachel Wynberg & Christine Jardine, Biotechnology and Biodiversity - Key Policy Issues for South Africa, 2000 said:
"This is a graphic illustration of the interconnectedness of life, and of the fact that the root of problems often stems from their purported solutions."
1. “Benefits outweigh the potential harmful effects.”
- Save Human lives by protecting against diseases like malaria, typhus and sleeping sickness.
- Prevent premature deaths of at least 7 million people from insect-transmitted diseases
- According to UN Food & Agriculture Organization
35% of food supply is lost to pest before harvest and 20% after harvest.
-37% of the potential U.S. food supply= 13% from insects, 12% to plant pathogens, 12% to weeds.
3. Increased Profit to farmers:
- for every $1 spent on pesticides leads to an increase in U.S. cope yields worth $4.
- if the data for what pesticides are used on the crops is include the profit is only $2.
4. They work faster and better than the alternatives:
- Control most pests quickly & at a reasonable cost
- have long shelf life
- are easily shipped and applied
- are safe when handled properly
- If genetic resistance occurs, farmers can use stronger doses or switch to other pesticides
5. Relatively Safe
American Council on Science & Health (ACSH)
- Health risks are insignificant when used properly
- Today’s pesticides are actually safer than those of the past
- Many of the new pesticides are used at a lower rate than in the past
Microbiologist, Bruce Ames states:
- consume more natural pesticides produced by plants than synthetic ones
- risk of getting cancer from natural & synthetic pesticides is small
- exposure to natural pesticides in food causes more cancers than exposure to synthetic
2. Broad Spectrum insecticides kill natural predators
- 1/3 of the most destructive pests are secondary pests that became widespread after the use of insecticides.
- the natural predator of the secondary pests were wiped out
Gypsy moth cateripllar
Number of species
Insects and mites
Fig. 20.4, p. 507
3. Pesticides Do Not Stay Put
- Less than 2% of the pesticides used actually reach the target pest
- Less than 5% of herbicide reaches the appropriate weeds
- Pesticides may end up in the air, water, bottom sediments, food or non-target organisms
4. Some pesticides harm wildlife
According to USDA & U.S. Fish & Wildlife Service, pesticides applied to cropland in the U.S.- each year
- wipe out more than 20% of honeybee colonies costing farmers $200 million in lost pollination
- kills 67 million birds
- kills 6-14 million fish
- hurt 20% of endangered species
5. Threat to Human Health
According to the WHO & UN Environment Program (UNEP)
- 3 million agricultural workers are seriously poisoned by pesticides each year
- 18,000 deaths (probably under estimated)
- 165 of the approved active ingredients are carcinogenic
- Exposure in food is related to 4,000-20,000 cases of cancer/year
- Birth defects, genetic mutations, nervous system disorders, immune system problems
- Pesticides are evaluated for biological active ingredients & their affects
*The amount of toxic residue that can legally remain on the crop when a consumer eats it.
- Danger & Poison (PELIGRO)
-Skull & cross bones
-Danger- No Skull/Cross Bones
-Significant Skin or Eye effects
-Slightly Toxic or relatively non-toxic
-U.S. companies can make and export banned chemicals to other countries
-26 tons per day
-Many of the crops the pesticides are used on return to the USA
-Bob Lake, director of policy at the FDA's Center for Food Safety and Applied Nutrition, says that the FDA does find illegal amounts of pesticide residues in 1-2% of domestic produce, and up to 5% of imported produce.
1. Excessive Pesticide Use:
One of the biggest problems with the use of pesticides is in
determining the Economic Threshold
- To protect themselves, farmers often practice Insurance Spraying and/or Cosmetic Spraying.
- They spray more pesticides to help yield a better crop.
- Buy insurance that pays them if their crops die from Pests
- Use more pesticides so their crops look better because consumers only buy best looking fruit and vegetables
2. Cultivation Practices:
- crop rotation
- changing planting times
- planting trap crops
- increasing habitat for natural predators
3. Create Genetically Resistant Plants or Genetically Modified Foods (GMO’s)
4. Biological Pest Control:
5. Insect Birth Control
-Males are sterilized using radiation and then introduced into a population to unsuccessfully mate with females.
- Sterilization of insects
- used with screwworms and fruit flies
-estimating mating times/behaviors
-need large # of males
- males must be reintroduced