Improvement of food resources of Class 9


9.3% food grain in our country are lost due to inadequate & improper  storage. Factors responsible for such a great loss during storage are as follows :

  • Biotic (living): Insects, rodents, birds, mites etc.
  • Insect – pests
  •  Common insect- pests include weevils, beetles, locusts, mites, aphids, grasshoppers, bugs and termites.
  • Insect – pasts damage/ harm the plants in following ways :
  • They cut root, stem and leaves.
  • They suck the cell sap from various plant parts.
  • They bore into stems and fruits.
  • They from falls.
  • They eat stored grains.


Rice weevil Khapra beetle and Pulse beetle

Some insect pests of stored grains

Abiotic (non-living) :

  •  Temperature
  •  Moisture
  •  Humidity
  •  Material of container in which grains are stored 

The above mentioned factors bring about :

  • Infestation of food grains by insects and microorganisms.
  • Degradation in quality.
  • Loss in weight.
  • Poor germination potential of grains.
  • Discoloration of product.
  • Unpalatable or even toxic food materials.
  • Finally poor marketability and lower profits. Thus, it is essential that loss of food grains during storage is avoided. The attack on food grains by insects and micro-organisms is called infestation. A general rise in the temperature of the grain and presence of patches of white powdery material on the bags or on the floor also indicates infestation of grain by insects. Presence of rodents can be detected by the excreta or tell – tale holes in the bags.

Related Topics 

Preventive Measures :

  • Drying before storage
  • Maintenance of hygiene
  • Plant – product treatment
  • Prophylactic  treatment
  • Improved storage structures 

Control Measures:

  • Pests are controlled by the use of chemicals called pesticides.
  • Fumigation is the most convenient and method of pest control in stored grains inside godowns.
  •  Fumigation are volatile (gaseous) chemicals that quickly vaporize and the resultant fumes kill the insects without affecting the grains. Utmost care has to be observed in handling of pesticides as these  are equally harmful to humans and domestic animals.

Disease causing agents (pathogens):

Many pathogenic organisms like fungi, bacteria, viruses, nematodes, etc, damage the plants and reduce the yield. These diseases are infectious and can be transmitted through soil, water and air. Some of these diseases are epidemic and cover a large area of population resulting in severe outbreak.


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