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Pesticides

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Introduction

What are Pesticides?
 
Pesticides are chemicals designed to control or kill pests. They are used to protect species that are beneficial to humans for a competitor or predator that is less useful. For example, farmers use pesticides on maize to protect it from harmful insects.

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What are Pests?

Pests are organisms that people consider harmful or inconvenient. They can seriously decrease the production of crops and livestock.

insects are the major pests. Pests such as  insects transmit serious diseases, such as malaria and typhus they also destroy or cause heavy damage to valuable crops, such as maize and cotton. Other common pests include bacteria, fungi, rats, and weeds.

Why are scientists concerned?
   
     

Scientists are concerned about pesticides because of the following reasons:
  • Prolonged exposure to pesticide raises risks of some cancers

  • Neurological problems like Alzheimers and Parkinsons diseases

  • Developmental problems

  • Weakening of immune system - vulnerable to disease

  • Decline in animal populations

  • Extinctions of some species

  • Damage to ecosystems and the environment

   

Classification of Pesticides
As there are many types of pesticides used, peticides can be gropuped itno four different categores:
  1. Insecticide - targeted on insects eg DDT
  2. Herbicide   - targeted on weeds   eg Silvex
  3. Fungicide   - targeted on moulds & fungi eg Captan
  4. Bactericides- targeted on bacteria eg penicillin

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