Q. Consider the following:

1. Birds
2. Dust blowing
3. Rain
4. Wind blowing

Which of the above spread plant diseases?

• 1 and 3 only
• 3 and 4 only
• 1, 2 and 4 only
• 1, 2, 3 and 4

Answer: (d) 1, 2, 3 and 4

Notes

• Birds moving through crops can carry pathogens from one infected plant to another plant.
• Some plant pathogenic bacteria are carried to short distance by wind.
• Some bacteria are often disseminated by splashing of raindrops, as in case of Citrus canker disease.
• In some places, rain seems to be more important than insects in disseminating the fire blight bacteria, by its washing or splattering effect of rain.
• Soil and field operations also disseminate the diseases as they result in dust blowing.

Plant Diseases

• A plant disease is usually defined as abnormal growth and/or dysfunction of a plant. Diseases are the result of some disturbance in the normal life process of the plant.
• Diseases may be the result of living and/or non-living causes. Biotic diseases are caused by living organisms (e.g., fungi, bacteria, and viruses).

Diseases caused by Bacteria:

Diseases caused by Fungi:

 Diseases caused by Virus: