Revelation 6:5,6 When he had broken the third seal, I heard the third Living Being say, "Come!" And I saw a black horse, with its rider holding a pair of balances in his hand. And a voice from among the four Living Beings said, " A loaf of bread for $20, or three pounds of barley flour, but there is no olive oil or wine." This Horseman also symbolizes economic collapse as a consequence of hyperinflation through food scarcity.
you're quote is wrong, A quart of wheat for a denarius (a day's pay), or three quarts of barley for the same price. No harm shall become of oil or wine. This symbolizes the struggle of the poor. This horseman will not only cause starvation but a clash of the classes. Oil and wine are luxury crops usually not damage by usual causes of famine, mainly locust and drought. The rich get to keep hold of their luxury crops and can still make money, while oppressing the poor, to whom the crops they value are in scarcity. In addition Oil and wine are used in christian sacraments
The First horseman's (white horse) nature is part of this, actually; it's been stated as Conquest and Pestilence alternatively. I guess you could call pestilence a conquest of sickness over the body... But anyway, if Conquest is the first horseman, Pestilence sometimes is combined with Famine because in real life, the two really can go hand in hand.