History

• In 1809, Swedish naturalist Karl Rudophi described the first roundworm and established the phylum Nematoda. Close to 20,000 nematode species have been identified.
  
  

Geography

• Nematodes are found in most types of soil, in most climates and at any elevation. They are present on the sea floor of all oceans and in the soil of all continents.
  
  

Features

• Nematodes have bilateral symmetry. They have an alimentary canal which extends from one end to the other. Nematodes have a digestive, nervous and reproductive system.
  
  

Life Cycle

• Nematodes go through six stages to reach maturity. This consists of an egg stage, four molting stages and the adult stage. The female can lay up to 27 million eggs in a lifetime. Fertilization occurs internally.
  
  

Considerations

• Nematodes can damage gardens and crops. Rotating crops, fallowing and solarization can reduce the number of nematodes in the soil.