Why does it matter which nozzle I use?
A nozzle controls both the speed of the flow of spray liquid (flow rate) and the range of spray drop sizes that are emitted and directed at the surface to be treated (target surface). Using the drop size advised is important as it also reduces the risk of spray drift and operator exposure. To spray in the best way, you need to use:
- the right nozzle to produce the right/required drop size; so that
- you achieve the right spray quality; and
- distribution pattern; in order to
- maximize the capacity of the pesticide to achieve its desired effect (its efficacy) and control the pest.
Different nozzles do different things and which nozzle is the right nozzle depends upon many factors such as
- how the pesticide ‘works’,
- the characteristics of the pest to be controlled as well as
- the nature of the target and
- the location of the pest on target surfaces.
Maximising the pesticide’s capacity to be as effective as possible, may not only require preferred drop sizes but also drop numbers. Some pesticides will move easily within a plant, for example, and hence it is not so critical to have good droplet coverage, whilst other pesticides will not move so easily and better coverage is necessary.
Flat Fan nozzles are often used on booms in linear arrays; they are recommended for overall, uniform swath spraying such as on field crop sprayers or minibooms on knapsack sprayers.
Hollow cone nozzles may be advised for insecticide and/or fungicide spraying as they produce smaller drop sizes.
Reflex nozzles can produce a wide swath from a single nozzle, can be used at low heights over the target surface and do not block easily; features that make them popular on knapsack sprayers.
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