When it comes to application season, spray nozzles are often an overlooked piece of a sprayer. Although usually the least expensive component, sprayer tips are one of the most important factors in weed control. If proper nozzles are not used, our ability to manage weed pressure decreases as weed resistance continues to climb. An operator’s overall goal should be to maximize weed control, use rates as the label requires, and minimize drift through the proper nozzle selection/ droplet size.
Every nozzle is designed for a specific application and rate. These parameters can help decide what tip is the best suited for our specific application:
1. Application target rate / speed / pressure
2. What is the product being sprayed?
(herbicide, fungicide, fertilizer, insecticide)
3. If herbicide, is it pre or post-emergence?
4. If fertilizer, what is the product weight?
5. Mode of Action (Systemic or Contact)
After answering the questions above, the next step is figuring out what spray nozzle size is required. When selecting a spray tip we usually size them by gallons per minute (GPM).
The following equation will help you in retrieving your flow rate.
GPM = (Gallons Per Acre x MPH X Spacing) / 5,940.
Example: Target rate is 20 gallons per acre, applied at 8 mph with 20” nozzle spacing at 35 PSI. We are applying a fungicide with a contact mode of action.
GPM = (20 GPA x 8 MPH x 20” spacing) / 5,940 = 0.54 GPM
In this example, a TeeJet XR11006 spray tip is what we decided to use. This spray nozzle will have a smaller droplet size which will allow for more surface area of the plant to be covered. In return, we should have a higher rate of success for weed control.
If you have any questions on what nozzles you should be using, TeeJet has a sprayer tip selection app called SpraySelect for android and apple devices or of course, you can give us a call for help too!