Organic Contaminants (Pesticides) Flashcards
pest=
any organism that damages crops that are valuable to humans
weed=
any plant that competes with crops
(type of weed depends of type of crop)
T/F
categorization of organisms into categories “pest” or “weed” is subjective
true
eg. dandelion (they’re edible!), ladybug
pesticide=
a poison that targets pest organisms (usually a specific one)
herbicide=
a poison that kills weeds
insecticide=
a poison that kills insects
fungicides=
a poison that kills fungi
Here is a list of other pesticides. What would each of them kill?
1. acaricides
2. molluscicides
3. nematicides
4. rodenticides
5. avicides
6. piscicides
7. algicides
8. bactericides
- mites
- snails/ slugs
- nematodes
- rodents
- birds
- fish
- algae
- bacteria
Inorganic pesticides usually contain ___, ___, lead, or mercury and are highly ____ in terrestrial environments
arsenic, copper
persistent (and can be dispersed by wind/ water)
Give 2 examples of inorganic pesticides and explain
- what they’re made of
- what they’re used against
- Bordeaux Mixture
- copper sulfate mixture
- used as a fungicide for fruit and veggie crops - Paris Green
- copper and arsenic compound
- used as a rodenticide and insecticide
- was used in green paint, and was extremely toxic!
Give 3 examples of organic pesticides and explain them + provide an example
- Natural Organic Pesticides
- extracted from plants
- most are insecticides
- examples: nicotine, caffeine - Synthetic Organometallic Pesticides
- mostly used as fungicides
- example: methylmercury - Phenols
- fungicides, used as wood preservatives
- example: pentachlorophenol (persistent organic pollutant, banned in north america)
biological pesticides are a type of ____ ___ that uses other ____ to remove/ kill pests
biological control
organisms
what’s a benefit of using biological pesticides?
Give an example of it’s use
doesn’t usually harm non-targeted organisms
eg. bacteria used to kill beetles/ flies/ butterflies
the highest household pesticide use is in ___ provinces
prairie
The federal government sets usage guidelines and licenses pesticides for use by ____ farms
BUT does not track total usage by ____
commercial
industry
Give 5 examples of diseases that have been successfully controlled/ eliminated thanks to pesticide use
- malaria
- yellow fever
- west nile virus
- plague
- lyme disease
For diseases spread by vectors, what’s the most effective way to control the disease? Give an example
remove the vectors!
- most are spread by insects –> kill them with insecticides
- remove breeding grounds for the vector
eg. DDT used to kill mosquitos to decrease the spread of malaria
Modern agriculture is fairly dependent on pesticides production and profit, but even with pesticide use, North America loses __% of all food/ fiber crop production from pests
37%
T/F
An estimated 99% of all canola is treated with herbicides to reduce weeds, and there is no pressure to use safe products
false
99% is regularly treated
BUT
there is also lots of pressure to use “safe” products
What term does this define?
= genetically modified strains of crops that are resistant to ___, used to kill a wide range of weeds
Roundup Ready Crops
glyphosate
what’s the benefit of using roundup ready crops?
the crop doesn’t die when the field is sprayed, only the weeds do
what are 4 downsides of using roundup ready crops?
- non-target toxicity: spraying still affects other organisms, even if not our crops
- evolution of resistance by weeds (sometimes the crop & weed interbreed)
- economic monopoly on seeds by Monsanto
- roundup ready plant tissue may be toxic to surrounding organisms
glyphosate is known to kill crops- what’s a solution?
make the crops resistant to glyphosate!
Can still spray the weeds
this is what roundup ready is
pesticides often kill organisms other than their ____
Give 2 examples
targets
- carbofuran (now banned) and birds
- pesticides and honey bee colony collapse disorder
Pesticides with ____ enter the food chain and bioaccumulate/ biomagnify
example=
organochlorines
ex= DDT (persistent organic pollutant, soluble in fats= it accumulates)
Dutch Elm disease was treated with ___.
What was an indirect (negative) effect of this?
DDT
robins ate the beetles from the trees containing DDT –> their eggshells became very thin (high mortality)
Describe the evolution of pesticide resistance in plants
pesticide is applied to plants that are being eaten by pests
- resistant pests survive and reproduce= more of the pests are resistant to the pesticide
We have to keep up by changing pesticides
= co-evolution! (Red Queen Hypothesis)
What’s a solution to the evolution of pesticide resistance in plants?
Refugia
- maintain a non-sprayed area where non-resistant pests can keep reproducing
- they breed with the resistant pests –> keep the non-resistant gene going
What is integrated pest management?
the use of multiple techniques to achieve long-term suppression of pests, including:
- bio-controls
- pest- resistant crops
- habitat alteration
- strategic use of pesticides
give an example of habitat alteration (integrated pest management)
remove the diseased plant before it can spread
As part of integrated pest management, there are 2 ways to use pesticides strategically:
- use them as a last resort! (don’t overuse)
- try to use botanically-derived compounds (generally less harmful)
malaria was fought directly with ___, which is the reason we started using it
DDT
T/F
Thanks to DDT, Malaria has been eradicated throughout the world
false
still a huge problem in places like Africa and South America
what are 3 problems we’re seeing with mosquitoes and malaria?
- anti-malarial medication resistance is increasing
- insecticide resistance is increasing
- climate change is increasing mosquito
Why is DDT resistance still increasing, even with very limited use of it?
because it’s a persistent organic pollutant (still around!), and we also use other pesticides that kill in the same way (becoming resistant to all of them)
The bottom line is:
We need to use ___ pesticides with multiple modes of ___
pesticides
action
