Definition: On the 25 of April (VII kal. Mai), the Romans from the time of Numa Pompilius -- according to Pliny -- celebrated a public festival known as Robigalia in honor of the god Robigus. Its purpose was to prevent mildew from ruining the fields. Sacrifice and prayer were offered by a flamen.
Examples:
In his "On Agriculture" I.1.6 Varro writes:
First, then, I invoke Jupiter and Tellus, who, by means of the sky and the earth, embrace all the fruits of agriculture; and hence, as we are told that they are the universal parents, Jupiter is called "the Father," and Tellus is called "Mother Earth." And second, Sol and Luna, whose courses are watched in all matters of planting and harvesting. Third, Ceres and Liber, because their fruits are most necessary for life; for it is by their favour that food and drink come from the farm. 6 Fourth, Robigus and Flora; for when they are propitious the rust will not harm the grain and the trees, and they will not fail to bloom in their season; wherefore, in honour of Robigus has been established the solemn feast of the Robigalia, and in honour of Flora the games called the Floralia.
In his April Fasti, Ovid writes about the Robigalia:
[905] On that day, as I was returning from Nomentum to Rome, a white-robed crowd clocked the middle of the road. A flamen was on his way to the grove of ancient Mildew (Robigo), to throw the entrails of a dog and the entrails of a sheep into the flames. Straightway I went up to him to inform myself of the rite. Thy flamen, O Quirinus, pronounced these words: "Thou scaly Mildew, spare the sprouting corn, and let he smooth top quiver on the surface of the ground. O let the crops, nursed by the stars of a propitious sky, grow till they are ripe for the sickle. No feeble power is thine: the corn on which thou hast set thy mark, the sad husbandman gives up for lost. Nor winds, nor showers, nor glistening frost, that nips the sallow corn, harm it so much as when the sun warms the wet stalks; then, dread goddess, is the hour to wreak thy wrath. O spare, I pray, and take thy scabby hands from off the harvest! Harm not the tilth; 'tis enough that thou hast the power to harm. Grip not the tender crops, but rather grip the hard iron. Forestall the destroyer. Better that thou shouldst gnaw at swords and baneful weapons. There is no need of them: the world is at peace. Now let the rustic gear, the rakes, and the hard hoe, and the curved share be burnished bright; but let rust defile the arms, and when one essays to draw the sword from the scabbard, let him feel it stick from long disuse. But do not thou profane the corn, and ever may the husbandman be able to pay his vows to thee in thine absence." So he spoke. On his right hand hung a napkin with a loose nap, and he had a bowl of wine and a casket of incense. The incense, and wine, and sheep's guts, and the foul entrails of a filthy dog, he put upon the hearth - we saw him do it. Then to me he said, "Thou askest why an unwonted victim84 is assigned to these rites?" Indeed, I had asked the question. "Learn the cause," the flamen said. "There is a Dog (they call it the Icarian dog),85 and when that constellation rises the earth is parched and dry, and the crop ripens too soon. This dog is put on the altar instead of the starry dog, and the only reason why this happens is his name."
FRAZER TRANSLATION
