The factors responsible for the loss of grains during storage are:

(a) Biotic factors- They are the living creatures like insects, rodents, mites, birds and bacteria. They feed on the various types of grains. A pest causes damage to agriculture by feeding on crops. For example, boll weevils a pest on cotton.

(b) Abiotic factors- They are non-living chemical and physical things. They occur due to moisture (present in food grains) , sunlight, temperature, wind and water they all have adverse effect of food grains leading to their loss. Some natural disasters such as droughts and floods are unpredictable. Their occurrence has a great impact on crops sometimes, destroying the entire crop.

These factors act on stored grains and degradation, poor germination, discoloration, etc.