What is "robigalia"

The Robigalia was a festival in ancient Roman religion held April 25, named for the god Robigus. Its main ritual was a dog sacrifice to protect grain fields from disease. Games ( ludi) in the form of "major and minor" races were held. The Robigalia was one of several agricultural festivals in April to celebrate and vitalize the growing season, but the darker sacrificial elements of these occasions are also fraught with anxiety about crop failure and the dependence on divine favor to avert it.