Then it changes into a chrysalis, or pupa, which is similar to a cocoon. Finally, the adult butterfly emerges from the chrysalis. Entomologists also study how insects can help us. For example, bees pollinate crops. Entomologists study how to help these insects do their jobs.
Some insects carry diseases that infect people, crops or animals.
Entomologists research how we can control them. Sometimes entomologists say to use pesticides. Other times they say to use biological controls, which means using another insect or disease to kill an insect. Often insects are controlled by a combination of several methods, which scientists call integrated pest management .