You searched for: “proliferation
proliferation (s) (noun), proliferations (pl)
1. The reproduction or multiplication of similar forms: The condition of rapid proliferation of mutated cells and morbid cysts, is something no one wants!
2. A rapid and often excessive spread or increase: The proliferation of anything can cause an overproduction, which, in turn, can cause an imbalance in the environment!

A dreaded proliferation of grasshoppers can cause the total destruction of grain fields.