Basics of koch postulate

What is Koch postulate?

In the identification of any plant disease the first step is to determine whether the disease is caused by an infectious agent or by environmental factor. Infectious agent usually characteristics symptoms on some part of the plant that reveal the presence and sometime the kind of infectious agent. Some infectious agent however, especially viruses may produce general systemic symptoms very similar to those caused by various environmental factors. If no pathogen can be found on or in a diseased plant and if the symptom presence are not the physical virus symptoms and cannot be consider as the cause of the disease. When a pathogen is found on the plant, the pathogen is identified by reference to special manners and if the pathogen is known to cause such disease then the identification may be consider completed. If however the pathogen found seems to be the cause of the disease but no previous exist to support this, then the following steps are taken to verify the hypothesis that the isolate pathogen is the cause of the disease. The procedure for proving this postulate can be summarised thus:

1.      RECOGNITION: The organisms in question must be found constantly associated with a particular symptom.

2.      ISOLATION: It must be isolated, grown and studied in pure culture.

3.      INOCULATION: The organism grown in pure culture must be inoculated into a healthy plant to produce the particular disease. The symptom produced in the inoculated plant should be the same as the symptom first observed.

4.      RE-ISOLATION: The organism must be re-isolated from the inoculated plant and compared with the first culture to be shown to be same as the original culture

I hope this little notes is of help.

 Yours sincerely,

Ajibade Tolulope Samuel.