When does ipm use synthetic chemical pesticides?

The IPM or Integrated Pest Management only use synthetic chemical pesticides as a last resort. The IPM is a way to deal with the pests. It aims to decrease the population of the pests below normal level to avoid mass destruction of crops by pests and other insects.  

Synthetic chemical pesticides are ruthless and efficient in doing their jobs but they also leave some damage behind. Most pesticides that use synthetic chemicals are harmful to the crops as well as for our bodies. Using them in large quantities is not recommended.  

your a sped   no one cares

your answer is "the 1950's"