Unit 4: Agriculture - Pests and Pesticides
- Created by: rosieevie
- Created on: 18-05-15 20:06
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- Pests and Pesticides
- Weeds
- Reduce crop yields by
- Competing
- Contaminating crop and spoiling taste
- Providing food for other pests
- Herbicides
- Hormone herbicides - systematic (absorbed) and modify growth or development e.g. unrestricted growth so plant runs out of food reserves
- Contact herbicides - damage cell membranes and leaf surfaces
- Reduce crop yields by
- Insects
- Reduce crop yields by
- Eat the crop
- Spoil crop appearance
- Spread diseases
- Insecticides
- Organochlorines e.g. DDT - overstimulates nerves causing death
- Persistent and lipsoluble = bioaccuum and mag
- Organophosphates e.g. malathion - prevent normal nerve function
- Very toxic to mammals
- Pyrethroids - overstimulates nerves
- Toxic to fish but biodegradable
- Organochlorines e.g. DDT - overstimulates nerves causing death
- Reduce crop yields by
- Micro-organisms
- Antibiotics
- Controls infections in sick animals
- Prevent infections occuring
- Reducing gut bacteria numbers to increase gross growth efficiency
- Problems - can cause antibiotic resistant zoonoses
- Zoonose - micro-organism that is carried by livestock and causes disease in humans
- Antibiotics
- Weeds
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