How Proper Sprayer Calibration Can Save Big on Crop Protection Inputs

In fruit production — especially in dense canopies like strawberries or vertical orchard systems — sprayer calibration is often the difference between pesticide waste and effective crop protection.

“In a simple sense, calibration is confirmation of the accuracy of material moved through the sprayer,” Megan Luke, a viticulture and tree fruit educator with the Penn State Extension, says. “You’re making sure the correct amount of material is going onto your plants, while assessing any issues with equipment.”

After two seasons of analyzing sprayer systems in the Lake Erie region, Luke has pinpointed three barriers to effective pest control — inconsistent coverage, poor water quality, and incorrect equipment setup. In addition, some growers are reluctant to adjust their equipment due to time constraints or already have confidence in their routines.

Yet a routine sprayer “check-up” is a professional benchmark and legal necessity for every commercial fruit operation. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), off-label application of a pesticide is a federal offense, Luke said during the Dec. 3 Lake Erie Regional Grape Program, an annual seminar hosted by the PSU Extension and Cornell Cooperative Extension.

“You get comfortable in your system, and if something isn’t terribly wrong, you’re not doing some of these time-consuming manual measurements,” Luke says. “But a lot of our labels say that we do need to calibrate our equipment. If that isn’t a reason, saving money and reducing risk of off-target applications is very important.”

A calibrated sprayer aligns speed, width, and flow rate to ensure the exact pesticide volume is delivered to the crop. Most farmers take these measurements before the season’s first spray or throughout the season when changing cropping systems.

INCONSISTENT COVERAGE

During her two-year field evaluation, Luke pinpointed faulty flow meter readings and inconsistent pressure as primary factors degrading spray uniformity. Nor were these the types of problems a farmer could easily spot from a tractor’s seat, she says.

“You can have coverage issues with a sprayer that may not be noticeable from the cab or even when you go back to look at the material applied,” Luke says. “This is not something you’ll necessarily see with the naked eye, or without those few extra steps that calibration requires.”

As even one clogged nozzle can throw off your coverage pattern, growers can measure output with a bucket. Output exceeding a manufacturer’s rating indicates a worn nozzle, while a lower output typically identifies a clog or pressure leak.

Farmers can compare their flow meter readings to manufacturer specifications as well. Although these digital sensors are valuable, physical collection will confirm that your equipment is performing as intended, Luke adds.

Calibrating a multi-row sprayer, meanwhile, requires comparing output among individual nozzles, sides, and panels. Activating the entire spray system will reveal the exact amount of product hitting the field.

“From side to side, your machine may be putting out different amounts of material,” Luke says. “You want to know if half your sprayer is putting out a different rate than the other side. There could be differences in the nozzles themselves, or panels on each side putting out different amounts of material, which can impact your coverage.”

POOR WATER QUALITY

Water quality can affect spray efficiency as well, with suspended solids clogging strainers and corroding nozzles. A simple water testing strip is an inexpensive means of evaluating pH, which even at moderate levels can destabilize your herbicides and impact insecticide efficacy.

For example, carbaryl’s residual efficacy is decimated by alkalinity — while it lasts up to 125 days at pH 6, it survives only 24 hours at pH 9.

“That’s a huge difference, so just be aware of your pH and water quality,” Luke says. “If you’re not adjusting your water or checking your pH, you can be negating your pesticides before they ever touch the plant. You want your active ingredients to have the perfect environment to work in.”

Ultimately, farmers are wise to follow the calibration instructions woven throughout most pesticide labels, Luke says.

“It’s usually a bullet point on a label, and the label is the law,” she says. “(Calibration) will ensure you’re using the correct amount of pesticides in a way that gives you the most benefit.”