After rising from a spike in agricultural demand for urea, diesel-exhaust fluid prices at the pump saw a sharp drop in July, according to DEF Tracker.

The average U.S. DEF pump price dropped dramatically between June and July, to $2.70 per gallon.

The fall comes after four straight months of rising prices, and this is the lowest average price recorded since DEF Tracker was launched in October 2011.

The average price of bulk DEF delivered to fleets by tote or to permanent storage installations fell in each of the six U.S. cities monitored by DEF Tracker (except Tampa, Fla., which saw a 1-cent increase), although by a far smaller margin than recorded at the pump.

Love's Travel Stops, which offers bulk DEF pumps at 150 of its locations, introduced a lower national pump price during July.

The decrease in DEF pricing is a reflection of falling raw material costs, as urea prices dropped in June.