Dear student.
Generally, the insect and pests follow the three ways mentioned below:
(i) They bite the root, stem and leaf.
(ii) They suck the cell sap from various parts of the plant.
(iii) By boring into stem and fruits.
Preventive measures are given below which can be used before grains are stored for future use:
1) Drying: Grains should be dried properly before storage as moisture attracts pest and insects.
2) Fumigation: Using chemicals and fumigants to keep away the pest and insects. These chemical are able to kill pest and insects.
3) Maintaining hygiene: Grains should be cleaned and then stored properly to avoid pest and insects.
Regards.