How could you use biotechnology to protect a plant from insect damage

Biotechnology could be used to engineer plants with resistance to a certain pest so that on infection by the pest the plant releases cytotoxins which can specifically kill the pest and prevent damage to the plant.

To protect plant form insect damage, I will make it into a transgenic plant. Transgenic plant are called genetically modified organisms (GMO) because there is a gene added or removed in the original plant to obtain a set of characteristic such as insect damage.