The Roman god associated with crop diseases and appeased during the Robigalia was Robigus. He personified the destructive force of agricultural disease, especially the reddish wheat rust that could threaten Rome’s grain supply.
Robigus was not simply a benevolent harvest deity. Roman farmers treated him as a dangerous power who could either inflict disease or hold it back, so ritual appeasement was meant to divert harm from the fields. The April festival Robigalia took its name from him and was held as crops entered a vulnerable stage of growth.
The tradition is complicated by ancient variation in the deity’s gender and name. Some writers use the feminine form Robigo, which is also the Latin word for wheat rust. Others, including Varro and Aulus Gellius, describe Robigus as male. The stored answer is the standard masculine form used by this question.
Red imagery was central: the disease was reddish, and ancient accounts connect the sacrifice, blood, and the color red with sympathetic protection against the blight.