3 ways insecticides can be counterproductive in agriculture

Some insecticides make pests stronger or put plants at greater risk of attack.

Pesticides are not new and are definitely not a human invention. Plants and other microorganisms have used chemicals to defend themselves from other organisms for hundred thousands of years.

Take, for example, walnut trees. Their roots produce a chemical called juglone that is secreted into the soil and inhibits nearby plant growth. This ensures the walnut tree has all the nearby nutrients and water for itself.

Plants also produce insecticides. Nicotine is the most famous example, produced by plants in the solanaceae family, including tomatoes, potatoes and, of course, tobacco. Many plant-eating insects avoid tobacco plants because nicotine is a powerful neurotoxin that can kill them.