Pesticides Brooke Le Fevre Victoria Sifuentes Rachel Herron

Pesticides Brooke Le. Fevre Victoria Sifuentes Rachel Herron

Introduction � What is a Pesticide? Any chemical that is used to kill insects, animals, fungi. Insecticide, Fungicide, rodenticide, and herbicides (examples) Pest- any organism that is unwanted � Persistent: pesticides that are stable and remain active for long periods of time � Non-persistent: pesticides that break down quickly � Target: specific pest causing the problem � Non-target: the organism, that is unintentionally killed � Biocide: when pesticides kill a large variety of things including humans � Bioaccumulation/Biomagnification

Insecticides � Used to control pests that feed on crops or plant diseases carry Causes prevention of huge losses � � � It can be done manually but it is not practical In ancient Greece Homer mentioned use of sulfur for controlling insects Disease carrying insects Mosquitoes carry 30 different harmful diseases to humans ▪ Malaria/ bubonic plague/sleeping sickness Chlorinated hydrocarbons Complex/ stable structured that contain carbon, hydrogen, and chlorine. (DDT)(chlordane) (aldrin). • Believed to affect the nervous system of organisms then resulting in death. • Persistent pesticide Organophosphates • Non persistent • More toxic • Interferes with nervous system • (anthion)(parathion) (diazinon) Carbamates • Non persistant • More toxic • Interferes with nervous system • (Propoxur)(Carbaryl) (Aldicarb)

Rodenticides � Target rodents - mice, rats, voles Can destroy food supply, bring disease, and damage crops in the field � Warfarin - causes internal bleeding (bait) Benefits • Prevents disease spread • Increases crop yield • Decreases food supply damage • Makes food more sanitary Drawbacks • Bait is harmful to any organism that eats it, including humans (kills nontarget organisms) • Rodents can become tolerant • Other organisms can be harmed by consuming poisoned rodents

Herbicides � Targets weeds - unwanted plants Agricultural, lawns and gardens, public areas 65% of pesticides used in the U. S. are herbicides � Auxins – a plant growth hormone, a lot can produce ethylene, which too much of causes harm or death Benefits Dramatically increase crop yield due to less competition and less manual labor Balancing the ecosystem Drawbacks Linger in the soil, leach or runoff into water Plants can build resistance over time

Fungicides Fungae (the problem) � Definition: Causative agents of crops that reduce yield/quality of food groups. � Can produce toxic compounds unfit to eat � Methylmercury – protects seeds from spoilage but = highly toxic to humans Fungicides (the solution) Reduce yield losses that are caused by disease Improve quality of appearance of harvested produce Reduces natural toxins fungi produces making it safer to eat. Protect products from spoilage

DDT Reasons for Use Disadvantages First synthetic Affected nontarget organic insecticide organisms Inexpensive, long Eagles, osprey, peregrine falcons lasting, harmless (egg hardness) to humans. And deadly to insects Persistent chemical Half life of 10 -15 years Prevented disease and increased crop Accumulates reaches yield higher concentrations in older animals and higher trophic levels � www. youtube. com/watch? v=ky. Ypw. OTta. LI&feature=related Silent Spring introduced the dangers of DDT and related compounds to the environment