Since ancient times farmers have controlled pests with ash, neem leaves, various herbal substances and organic materials. Chemical pesticides appeared after the Industrial Revolution, and their widespread use began in the mid-20th century.

On the bottle or packet of an insecticide or pesticide you will see a mark in one of three colours: green, yellow or red. What does it mean, and why do companies use these colours? Here is the reason.

• Green: less hazardous. The crop must not be harvested, marketed or eaten within 5-7 days of application.
• Yellow: highly hazardous. The crop must not be harvested, marketed or eaten within 10-15 days of application.
• Red: extremely hazardous. The crop must not be harvested, marketed or eaten within 20-35 days of application.

Pesticides kill the insects on crops. Even if eating those crops does not kill us, pesticides destroy various cells in our bodies. In old age, when the body's immunity is weak, those damaged cells cause various diseases. Misuse of pesticides can lead to cancer in the human body.

Source: Jagonews24. First published in Bengali on The Agro News.