The artificial and naturally derived chemicals that kill insects are known as insecticides. It can be selective by targeting a particular type or group of insects. But there are also several insecticide chemicals which do not target any specific type or species of insects and can kill all the insects in the area it is applied. Both the types of insecticides are used in agriculture. But  care must be taken while using non- selective chemicals for it can kill beneficial insects present in a crop field.