13 - Environmental impacts of organic contaminants: Pesticides

Question 1

What are pests

Answer 1

Any organism that damages crops that are valuable to humans

Question 2

What is a weed

Answer 2

Any plant that competes with crops

Question 3

Pesticide vs herbicide vs insecticide vs fungicide

Answer 3

Pesticide = a poison that targets pest organisms

Herbicide = a poison that kills weeds

Insecticide = a poison that kills insects

Fungicide = a poison that kills fungi

Question 4

Two classifications of pesticide

Answer 4

Inorganic and organic

Question 5

Inorganic pesticides usually contain what? Characteristics of IP? Example?

Answer 5

Usually contain arsenic, copper, lead, or mercury

Highly persistent in environment

E.g.
Bordeaux mixture: copper sulfate mixture, used as a fungicide for fruit and veggie crops

Question 6

Categories of organic pesticides? Where do they come from?

Answer 6

Categories: natural organic pesticides, synthetic organometallic pesticides, phenols

Extracted from organisms (like plants or fungi) when naturally produced OR can be synthetically produced

Question 7

Examples of natural vs synthetic organic pesticides

Answer 7

Natural: nicotine, caffeine

Synthetic: methylmercury, DDT, chlordane

Question 8

Reasons for using pesticides

Answer 8

• human health (vector control)
• agriculture

Question 9

Examples of diseases that can be controlled through pesticide use

Answer 9

• malaria
• yellow fever
• plague
• West nile virus
• Lyme disease

Question 10

Most effective way to control diseases spread by vectors

Answer 10

Remove the vectors:
- most spread by insects (use insecticides)
- remove breeding grounds e.g. wetlands for mosquitoes

Question 11

How do pesticides help agriculture?

Answer 11

Fewer pests = fewer losses = increased production = increased profit

Even with pesticides, NA loses 37% of food and fiber production from pests

Question 12

What are Roundup ready crops? Good and bad of this technique

Answer 12

Genetically modified strains of crops that are resistant to glyphosphate, used to kill wide range of weeds

Good: spray the field, kill the weeds, keep the crops

Bad: non-target toxicity, evolution of resistance by weeds

Question 13

Three concerns with Roundup ready crops

Answer 13

1. Roundup ready crops may crossbreed with weeds to produce glyphosphate resistant weeds
2. Roundup ready plant tissue may be toxic to other organisms
3. Economic monopoly by single company: Monsanto

Question 14

How can pesticides impact non-target organisms? Example

Answer 14

Pesticides often kill organisms other than their targets

E.g. birds can ingest pesticides directly when feeding or indirectly through other food

Slide 18

Question 15

Solution to evolution of resistance by pests

Answer 15

Refugia

Do not spread pesticides everywhere on the field so some non-resistant beetles remain and reproduce and some beetles remain sensitive

Question 16

What is Integrated pest management? Forms

Answer 16

The use of multiple techniques to achieve long-term suppression of pests, including:
- bio-controls (biological controls)
- pest-resistant crops
- habitat alteration
- better pest monitoring
- strategic use of pesticides

Question 17

What are biocontrols? Three types and examples

Answer 17

Utilize organisms to eliminate pest organisms

Predators: ladybugs to control aphids
Parasites: parasitoid wasps to control many pests
Pathogens: rabbit hemorrhagic disease to control rabbits in AUS and NZ

Question 18

What are pest-resistant crops?

Answer 18

Genetically modified crops
Some will produce crystal protein that can kill insects

Question 19

Strategic use of pesticides in IPM

Answer 19

• use as a method of last resort
• try to use botanically-derived compounds