exam 4 Flashcards
narrow spectrum pesticides
kill a specific organism
broad spectrum pesticides
kill a wide variety of organisms
1st generation pesticides (pre 1940s)
naturally derived compounds.
minerals and heavy metals, botanicals
minerals and heavy metals
As, Pb, Hg
persistent and highly toxic to humans
botanicals
nicotine, pyrethrin
not persistent, toxic to aquatic organisms and pollinators
2nd generation pesticides
Post WWII
synthetic ex: DDT
Chlorinated Hydrocarbons (e.g. DDT)
Persistent, broad spectrum
banned or restricted
Organophosphates (e.g. malathion)
not persistent, broad spectrum, most toxic, used in agriculture
Carbamates (e.g. carbaryl)
not persistent, broad spectrum, less toxic, less effective
Selective herbicides
kill specific plants
broad leaf and grass herbicides
2,4-D
non selective herbicides
kill all vegetation
Glyphosate
toxic to amphibians
glyphospate
epa declared unlikely carcinogen
PFAS
added to pesticides to make them last longer
benefits of pesticides
disease control (ticks and mites) and crop protection (save $)
how to deal with pesticide resistance
sacrifice plants, mechanical weed removal, introduce natural predators
problems with pesticides
genetic resistance, kill non target species, environmental mobility, human health risks
environmental mobility of pesticides
found in surface water such as streams and drinking water
found in antarctic krill
short term exposure to high levels
harms organs, nervous system, potentially deadly
long term exposure to low levels
sterility, cancer, birth defects, miscarriage, slowed development, parkinsons disease
cultivation alternatives to pesticides
intercropping, embrace weeds, crop rotation
biological alternatives to pesticides
use natural predators but may become invasive
pheromone and hormones alternative
pheromones used to lure insects into traps
reproductive control alternative
sterilize males with radiation, chemicals, or genetic alternation
genetic control alternative
genetically modified crops