ABSTRACT
Bacteria may or may not have mobility appendages, that is, flagella for their movement. The bacterial movement with the help of their flagella is called true motility. Sometimes, the bacterial movement can be mistaken for the Brownian movement. The plant pathogenic bacteria have the flagella appendages which help them to move in a thin film of water on the plant surface to reach the entry point to cause infection. Hanging drop preparation is useful for microscopic examination of living bacteria without staining them and to see their motility due to flagella. The random movement of microscopic particles suspended in a liquid or gas, caused by collisions with molecules of the surrounding medium, is known as Brownian movement. Virulent isolates of Erwinia carotovoravar. zeae spread horizontally to a greater distance from the point of stabling on either side in Petri plate than nonvirulent isolates as evident by the formation of bacterial colonies.
