Abstract: An attachment 1 for a hand gun 2 with a movable piston 4 actuated by a trigger means 11, which comprises a blade 3 to form a cut in a tree, and a fluid injection means 10 which instantaneously supplies a fluid dosage to the cut. The fuel to operate the hand gun 2, together with the fluid, are preferably provided in a backpack 43.

Abstract: In spraying liquid herbicides and insecticides, a predetermined dose is delivered in each operation of a dosing apparatus. The dosing apparatus comprises a piston-and-cylinder combination supported on a hangle. The piston is biased in one direction by a spring or by pressurized propellant, and movement of the piston in this one direction causes the liquid to flow into the cylinder through a check valve. Actuation of a trigger-operated valve releases pressurized propellant into the cylinder on the opposite side of the piston (or alternatively into an auxiliary cylinder) causing movement of the piston and discharge of the liquid through a second check valve and then through a spray nozzle. The dosing apparatus includes a portable backpack structure molded of a plastics material, and is especially suited for portable operation in remote locations. The backpack is formed with a reservoir for reagent and a compartment for removably holding a pressurized propellant container.