The "built-in protection" is achieved by the plant producing its own pesticide, in the form of a toxin, so you don't have to spray it. Look for "BT corn". It is

The "built-in protection" is achieved by the plant producing its own pesticide, in the form of a toxin, so you don't have to spray it. Look for "BT corn". It is argued that it is safer since the dose is lower, but you can't really be sure it is totally harmless either. (And apparently the soil is contaminated by the plant as well)