The Roman festival featuring a red-dog sacrifice to prevent wheat rust was the Robigalia. Held on April 25, it was designed to protect growing grain from robigo, the reddish disease identified with wheat rust.
The festival took place at the sacred grove of Robigus, traditionally located near the fifth milestone of the Via Claudia. A priest led prayers asking the destructive force of crop disease to spare the fields. Ovid’s Fasti provides the fullest surviving literary account, though the details reflect Roman religious and poetic traditions rather than a modern agricultural treatment.
The red dog was not an arbitrary offering. Ancient explanations connect the dog’s coat and the sacrificial blood with the reddish color of the blight, using sympathetic symbolism to counter the disease. Games and races, known as ludi, were also part of the observance.
Robigalia is often confused with other Roman spring festivals such as Parilia and Lupercalia. Those had different purposes and rituals; Robigalia was specifically concerned with protecting grain from disease.