Spraying pesticides? Selecting the sprayer nozzle should be the easy part.

Choosing the wrong spray nozzle can be a costly mistake.

Improper nozzle selection can be expensive if re-spraying is required, performance is reduced or legal issues arise as a result of chemical drift. Take a few minutes to review your spraying requirements, and be prepared to have multiple nozzle sets on hand to meet your needs.

Spray nozzles are highly engineered, precision components.

Even a spray nozzle with only 10% wear may not give you the coverage and performance you require. The cost of replacing nozzles is minor compared to the consequences of poor spraying.

The spray nozzle you select will determine:

• Amount of chemical applied to an area
• Uniformity of the application
• Coverage of the chemical on the target surface
• Amount of potential drift

Three common types of spray nozzles include:

Droplet size is a key factor in nozzle selection:

The ASABE (American Society of Agricultural and Biological Engineers) S572.1 standard uses eight droplet classifications ranging from extremely fine to extremely coarse. Keep in mind that droplet size decreases as your sprayer pressure increases.

• Fine droplet sizes are used for contact fungicides and insecticides or contact herbicides that require adequate retention on leaves.
• Medium droplet sizes are the most widely used and are typically good for systemic herbicides, insecticides and fungicides.
• Coarse droplet sizes are used with systemic, residual and soil-applied herbicides or to minimize spray drift.

How to Identify Spray Nozzles

Nozzles have markings that will identify their performance specifications, including spray angle, flow rate and material. The color will also identify its flow rate at 40 psi. Red nozzles, for example, have a flow rate of 0.4 gallons per minute at 40 psi. These colors are different than the ones used to classify droplet size.