Robust crops not only withstand insect attacks more successfully than other crops, they are also less likely to be attacked in the first place, since insects tend to feed on weaker plants  Killing insects with pesticides does not address the underlying problem of inherent vulnerability to damage caused by insect attacks
Thus, a better way to reduce the vulnerability of agricultural crops to insect pest damage is to grow those crops in good soil -- soil with adequate nutrients, organic matter, and microbial activity
Crops that are grown in good soil tend to be more robust than other crops.