Question

farmers use insecticides to kill insects that damage the crops. these also kill dragonflies. how can killing dragonflies be harmful to us?

Answer 1

Insecticides are substances used to kill insects.[1] They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity.[2] Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain.