What is the advantage of growing genetically engineered Bt crops over spraying Bt on the crops?

The advantage of growing genetically engineered BT crops are increased crop yields, reduced pesticide use, less environmental damage, less fungal contamination and reduced labor.

Explanation:

Bt is a soil bacterium whose genome contains genes for several proteins toxic to insects. When it is sprayed on the surface of crops, Bt toxins breakdown quickly when exposed to ultraviolet light, and also wash them in a strong rain.

They offers environmental and economic benefits to farmers with increased crop yields, reduced pesticide use, less environmental damage, less fundamental contamination, and reduced labor.

Thus the advantages of growing genetically engineered Bt crops over spraying Bt on the crops include lower production cost, less pest problems, and better yields.