generally insect pets attack the plants in three ways
1. they cut the root, stem and leaf
2.they suck the cell sap from various parts of plants
3. they bore into stem, they thu affect the health of the crop and reduce yields
The insects or the pests attack the plant because they have the important urge.
This urge is to complete their life cycle. They attack the plant so as to eat them.
This they do out of their liking.
To avoid insects and to protect the plant, it is recommended to use pesticides..