Abstract: A mobile liquid spray apparatus comprises a wheeled frame of lightweight but sturdy construction which may be propelled manually over the ground or may be towed by a towing vehicle. The frame includes a height-adjustable horizontally extending spray boom, an attachment for a pair of vertical spray booms and a self-contained liquid supply system for delivering liquid under pressure selectively to the respective spray booms. The liquid supply system comprises a liquid supply tank on the frame, and a battery driven pump for delivering liquid under pressure from the tank selectively to the spray booms through a manually settable three-way valve. The system also includes a pressure regulator valve and pressure gauge for adjusting the spray pressure. The device may also include an auxiliary hand-held spray gun which may be used in place of one of the spray booms.