Disease Organisms, Prevention And Control In Agriculture

.     Bacteria

2.     Fungi

3.     Virus

4.     Nematode

1.      Bacteria: These are micro-organisms which can not be seen with naked eye unless we use a powerful microscope. Bacteria are found every when even under a condition where other living organism cannot exist such as in water in soil in the air in plant in animal, etc

 

Bacteria: These  are useful to man in the following ways:

i.                    The help in the decomposition of compost  and organic materials.

ii.                  They are useful in the fermentation process e.g. production of drinks such as beer, wine, etc.

iii.                They are also useful in the making of cheese.

iv.                They also help to fix atmospheric nitrogen into the nodules of legumes..e.g Azotobacter, Nitrosomonas.

On the other hands, bacteria causes crop disease which are transmitted  from one plant to another by wind, rain splash and by insects.
Examples, of such disease include the following Bacteria Blight of Cotton, Bacteria Blight of Guinea Corn,

Bacteria Wilt of tomatoes.

 

2.      Fungi: These are also microscope organism and they are regarded as plant but they do not process chlorophyl root, stem and leaver. But they leave as parasite on plant and transmitted of disease or diseases e.g. maize, smut, leave rust or leave spot, black pour, of cocoa, damping off, can be transmitted by wind , rain splash , by insect, etc.

3.      Virus: These are microscopic  organism, smaller than Bacteria and Fungi.They can only be seen under very powerful microscopic or electronic microscopic. They cause serious and civil diseases in crop plant. Virus diseases are transmitted by piercing and sucking insects. Disease cause by viruses include Coca Swollen Shoot, Groundnut Rosette,  Cassava and Yam Mosaic, etc.

 

4.      Nematode: These are soil born organism. They are worm like animals. Many of them live on dead organic matter while others live as parasites on plants. Some are microscopic while others are  big enough to be seen with naked eye. The parasitic nematode  attack plant hosts and caused diseases such as  Tuber rot, Root knot, Die back, etc.

       

SIGNS AND SYMPTOMS OF CROP DISEASES

1.      Yellowing and wilting of plants leaves

2.      Curling, twisting and winkling of leaves.

3.      Stunted Growth.

4.      Rottening  of leaves, stems and roots.

5.      Defoliation of plants

6.      Brown patches  with spots showing dead areas on leaves.

7.      Mouldy grains.

8.      Death of Plants

9.      Reduced product quality.

1.  Low Yield.

 

EFFECTS OF DISEASES ON CROP

1.      Poor yield

2.      Low quality and loss of market value.

3.      Delayed maturity.

4.      Death of crops