Ministry of Agriculture

Airblast sprayerPesticide Application Equipment

Equipment Types

Hand operated sprayers 

Hand operated applicators are generally used to apply small quantities of pesticides both inside structures such as greenhouses or for small jobs outdoors such as on small farms or spot treatment on larger farms.

Hand-held sprayers usually have an air pump which compresses air into the tanks and pressurizes the spray mixture. The pressure slowly drops as the liquid is sprayed. When the pressure gets too low, the nozzle spray pattern is poor. You must stop spraying and pump to rebuild the pressure. These sprayers operate at low pressures of 350 kPa (50 psi) or less and have small tanks of up to ten litres.

Back-pack sprayers are fitted with a harness so the sprayer can be carried on the operators back. Tank capacity may be as large as 20 litres. A hand lever is continuously operated to maintain the pressure which makes the back-pack sprayer output more uniform than that of a hand-held sprayer. Basic low cost backpack sprayers will generate only low pressures and lack features such as high-pressure pumps, pressure adjustment controls (regulator) and pressure gauges found on commercial grade units.

Basic low pressure hand operated sprayers are suitable for high-volume or dilute spraying where uniform coverage is not required. Sprayers equipped with pressure regulators and gauges and high pressure pumps (above 550 kPa or 80 psi) may be used for applying insecticides and fungicides.

Obtaining uniform coverage of an area is difficult with a hand operated sprayer. The operator must move the nozzle from side to side with proper overlaps and move at a steady pace. Motorized sprayers typically produce more consistent sprayer outputs, cover the spray swath more uniformly, operate at constant speeds and result in much more uniform coverage than hand spraying. Motorized sprayers are also capable of higher pressure sprays where required to provide better coverage.

There are many other types of hand operated sprayers that are not widely used throughout the agriculture industry. Some may be used extensively for the production of specific commodities.

Motorized sprayers 

Motor powered sprayers offer many advantages over hand operated sprayers. Powered sprayers can provide high pressure sprays and the power can be used to drive agitation systems, fans for air-assisted or airblast spraying, and transporting large volumes of spray mix. Properly equipped and operated, power sprayers can provide uniform coverage on a wide variety of targets. These systems can be mounted on tractors, trucks, trailers, and aircraft. Some backpack sprayers are also motorized.

Boomless sprayers

Motorized sprayers may be used to supply spray mix to a hand gun or hand held boom with several nozzles. With this equipment, the spray uniformity will be similar to a hand operated sprayer.  However, the sprayer pressure may be constant and the operator is able to cover larger areas or targets than with a hand operated sprayer. Hand guns are useful for spot treatments and treating small areas.

Boomless nozzles are also used to broadcast pesticides in areas not easily accessed by a boom sprayer. With this equipment good distribution of spray is obtained but the uniformity is not as good as with a properly operated boom sprayer. Boomless nozzles may be suitable for use in rough areas, and along fencelines and roadsides.

Boom Sprayers 

Most sprayers distribute pesticides using a boom with spray nozzles spaced at regular intervals. The most common example would be wide horizontal booms used on field sprayers to spray field crops. Depending on how the motorized sprayer is equipped, these sprayers can be used for a wide variety of tasks. A high degree of spray coverage uniformity is possible with constant spray pressure through uniformly spaced nozzles traveling at constant speeds.

Boom Sprayer Boom Sprayer operating
Boom Sprayers  

Low pressure boom sprayers are often used for spraying herbicides and in some circumstances insecticides and fungicides. Insecticides and fungicides are often applied to larger plants with more foliage and may require finer droplets to obtain good coverage of the foliage, especially if the target is the undersides of leaves in dense canopies. High pressure boom sprayers are often used in these circumstances. High pressure sprayers require pumps, hoses, nozzles and other components that can develop and withstand the higher pressures, resulting in sprayers that are more expensive.

Sometimes sprayer booms are mounted vertically to spray some crops such as blueberries, raspberries and occasionally nurseries. Nozzle spacing and the boom distance from the target are important in both horizontal and vertical booms to achieve good coverage.

Airblast sprayers 

Airblast Sprayer Airblast sprayer
Airblast Sprayers  

Most boom sprayers rely on pressure to move the spray mixture through a small opening in the nozzle and to create the small droplets and speed necessary to achieve good spray coverage of the target. In field crops good coverage is relatively easy to achieve where the target foliage is small and close to the nozzles. In tree fruits, especially with large trees, good coverage with conventional sprayers is more difficult to achieve. Airblast sprayers direct the spray mixture from the nozzles into an air stream which transports the spray droplets to the target. Airblast sprayers have a powered fan which forces air through an opening to generate high air speeds. Often the opening or manifold can be adjusted to ensure that the air stream is directed at the target. These sprayers are also used in other commodities such as grapes, blueberries and nursery crops among others.

In conventional airblast sprayers most of the air movement is upward into the trees or target. Tower air manifolds are also available for airblast sprayers which direct the air horizontally or even downwards towards the target. The horizontal or downwards air movement minimizes drift from airblast sprayers.

Tower sprayer Tower Sprayer
Tower Sprayer  

Granular applicators 

Granular applicators are used to apply granular pesticides to soil. Granules must be incorporated (mixed in with the soil) during or immediately following applications. Incorporation in the soil prevents birds from eating the granules; also, contact with soil moisture activates the pesticide.

There are several types of equipment for granular application. Some granular applicators can be hand operated and may use gravity to deliver the granules while others are powered such as the pneumatic applicators which use a stream of air to carry granules through the delivery tubes.

Aerial applicators 

Some pesticide labels say the pesticide can be applied by either fixed-wing aircraft or by helicopters. The main advantage of aerial spraying is that it can be carried out quickly and at times when ground equipment cannot operate. The main disadvantage is the increased possibility of pesticide drift onto neighbouring areas and decreased spray coverage. Even when properly calibrated and operated, aircraft sprayers are often not as thorough in applying material as ground rigs, especially to the lower surfaces of the leaves and to the lower portions of the plants when the foliage is dense.

Aerial applications should not be used for small acreages or in residential areas, and should be done only by properly trained individuals who hold a valid BC pesticide applicators certificate. Information on aerial applicator courses and pesticide applicator certificates can be obtained from the Integrated Pest Management Program, BC Ministry of Environment, or from the certification and recertification section on this web site.

Other applicators 

There are many other types of pesticides applicators. Many are specialized applicators or have not been widely adopted. There are many variations on the type of equipment that has been described as well. Very high pressure sprayers, foggers and misters are used in the greenhouse sector to apply very fine droplets in an enclosed building. This equipment is also used in mushroom production and other situations with enclosed areas.