Why should preventive measures and biological control methods be preferred for protecting crops?

• Preventive measures and biological control methods should be preferred for protecting crops because these methods are safe ecologically and do not harm other life forms.
• Excessive use of chemicals can lead to many environmental problems and cause pollution. They can also enter the food chain and cause serious health hazards.
• Biological control methods involve the use of biological organisms and hence, these are completely safe for other life forms.