Hippos are considered "grazers" meaning they eat grass. However, hippos are notorious crop raiders. In just one night, a few hippos can do a lot of damage. Hippos will make quick work of crops such as maize, sweet potatoes, cabbages, and sugar cane. The crops that the hippos don't eat may still get trampled as the hippos make their way through the fields.
In many countries, a farmer can file a complaint if hippos are threatening or have damaged crops. When a complaint is received, officials can kill the hippos. Unfortunately, farmers have sometimes been suspected of filing false claims of damage against hippos so they won't have to worry about the hippos later.