How are selective herbicides different from nonselective herbicides?

In the study of botany and weed management, herbicides are categorized based on their impact on plant life:12

• Selective herbicides: These agents are designed to target and affect specific plant species while leaving others unharmed. They are frequently used in agriculture to eliminate weeds without damaging the desired crops, such as using specific sprays to remove broad-leaved weeds from cereal fields.12
• Nonselective herbicides: These agents affect plants generally, typically killing or inhibiting the growth of most vegetation they contact. They are often used for broad-spectrum control where total vegetation removal is required.12

Both categories can be further classified by their method of application—such as foliage-applied or soil-applied—and their timing relative to crop growth, including preplant, preemergence, or postemergence treatments.12