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Good morning!. Please get out objectives #1-3 for a stamp . Make sure your food journal is up to date. Pesticides – “To use or not to use?”. What you already know about pesticides . . . . What is a pesticide? How are they used in general?
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Good morning! • Please get out objectives #1-3 for a stamp. • Make sure your food journal is up to date.
What you already know about pesticides . . . . • What is a pesticide? • How are they used in general? • What did we learn about monoculture crops and pesticides yesterday? • How are they used in Houston? • How are they used in our homes? • Do YOU ever come into contact with them? • What are the advantages/disadvantages?
Monocultures • What advice would the Inca have given the Irish?
Pests and diseases generally are plant-specific. • Examples – • Boll weevil attacks cotton plants • Rust fungus attacks corn • Yellow rust fungus attacks wheat
Diversity protects harvests from pests and diseases because they run out of food.
Pesticides can move through the environment • Monocultures are often crop dusted by planes. • If it rains soon after application, pesticide can runoff into local stream.
What happens in a farming community’s watershed? • Where would the greatest concentrations of pesticide be?
Biomagnification: the accumulation of a toxin as it moves up the food chain
Genetic Resistance • Individual pests can tolerate different amounts of pesticide. Some individuals are stronger than others and they can survive.
The pesticide treadmill • Pests develop resistance to pesticide • Farmer must use Increased dosage, application schedule, increased toxicity • It’s like a treadmill because once a farmer starts, it’s hard to stop using pesticides.
The Tradeoffs! • Advantages • Disadvantages