So why do we still use DDT compared to other insecticides since it is so harmful?

• A Firstly, DDT lasts longer than alternative insecticides; hence it needs to be applied less frequently. A degree of persistence is often desired in chemicals. If microorganisms degrade as soon as they were applied, they would not serve their desired function.
• According to the UN, Persistence is defined as having a half-life of more than six months in soil greater than two months in water.
• Also, alternative insecticides are more expensive, toxic and not as effective.