Handgun Sprayers

Handguns are basically hand sprayers with an engine-powered pump. Hydraulic handheld gun sprayers might be equipped with more than one nozzle. The multiple-nozzle guns are, in effect, very small handheld boom sprayers. A handgun is connected by a hose to a powered pump. Two or more handguns can be used on one pump if its capacity is sufficient. Piston or diaphragm pumps are usually needed to provide the required high pressure. Because the pump and tank are carried or towed by tractors or other vehicles, their tanks can be much larger than is feasible with the knapsack sprayers. This permits using more water and fewer refills.

As with any hydraulic nozzle, the handgun sprayers use pressure to atomize the spray liquid into droplets. The droplets' velocity when discharged from the nozzle must carry the spray to the target. The farther the tree is from the handgun, the higher the pressure must be to adequately deliver the droplets. Handguns with pistol grip-handled valves are preferred for spraying fruit trees because the operator can turn off the spray easily when going from one tree to the next.

Because the operator controls the travel speed, or time at each tree, variation in application rates similar to those of the knapsack sprayer can be expected. Long and heavy hoses contribute to operator fatigue and result in less uniformity. Some people build platforms on the sprayer or tractor on which the handgun operator can ride. This provides comfort but limits maneuverability. If you do build a platform, be sure that guards and railings are adequate to protect the operator.

Two or more people often are used in handgun spraying--one (or more) operates the handgun(s) and one drives the tractor through the plantation. This increases the number of people involved in comparison to knapsack spraying but allows treatment of many more trees in a given time period.