The differential grasshopper (Melanoplus differentialis) is a species of grasshopper belonging to the genus Melanoplus found throughout northern Mexico, central United States and southern Ontario, Canada. It is considered a pest in most of its range.he differential grasshopper (Melanoplus differentialis) is a species of grasshopper belonging to the genus Melanoplus found throughout northern Mexico, central United States and southern Ontario, Canada. It is considered a pest in most of its range.