When applying pesticides, the goal is to achieve 100 percent pest control with 0 percent spray drift.1 As University of Nebraska Extension specialists note, that’s a tall order when you can’t control all the variables. It’s important to focus on those you can.
Spray drift is the movement of droplets through the air, during or after application, to a site other than the intended target.2 Many factors influence spray drift, but university researchers say these three are most important:3
- Wind speed. When wind speed doubles, it results in an almost 70 percent increase in drift 90 feet downwind from the sprayer. Spray when the wind speed is 10 mph wind or less.
- Boom height. When boom height rises from 18 inches to 36 inches, the amount of drift increases 350 percent 90 feet downwind. Consider AutoBoom™ automatic boom height control for your Patriot® series sprayer to help maintain boom height.
- Distance downwind. If the distance downwind is doubled, the amount of drift decreases five-fold. If the distance downwind goes from 100 to 200 feet, you have only 20 percent as much drift at 200 feet as at 100 feet. You might need to spray only part of a field and then finish when conditions change.
Watch for air temperature inversions
Air temperature inversions occur under what we typically would consider ideal conditions for spraying — clear and calm. But these situations also provide conditions conducive for tiny, aerosol-size droplets to drift away from their targets.4 This Extension publication from North Dakota State University provides a detailed explanation about temperature inversions, how they occur and what conditions are conducive to temperature inversions.
Pick the right nozzles and maintain them well
Spray droplet size plays an important role in drift. Generally, small droplets do not have enough mass to drop fast, so they remain airborne and exposed to air movement longer than larger droplets.5 But drift is just one consideration in drift management. Insecticide and fungicide applications typically require smaller droplets for the best results. Consult the product specimen label for the recommended droplet size. Select a nozzle that balances product effectiveness and drift potential.
Regardless of the nozzle, take steps to ensure they’re doing the job. Nozzles wear. Change them as they age to ensure consistent, accurate application. A sprayer performance kit — which includes a calibrator — from your Case IH dealer can help. Your Case IH dealer also carries the latest nozzles and can help bring the most up-to-date application-equipment to your operation.
Sprayer nozzle selection and performance can have a big impact on your bottom line, along with adjacent fields and crops. So, give your nozzles the attention they deserve throughout the season.
RESOURCES
1Klein R. Improving Pesticide Efficacy and Managing Spray Drift. University of Nebraska Institute of Agriculture and Natural Resources website. http://cropwatch.unl.edu/2016/improving-pesticide-efficacy-and-managing-spray-drift. Published March 27, 2016. Accessed May 10, 2017.
2Hofman V, Solseng E. Reducing Spray Drift. North Dakota State University Extension Service website. https://www.ag.ndsu.edu/pubs/ageng/machine/ae1210.pdf. Published June 2001. Accessed May 10, 2017.
3Montana State University Extension Pesticide Education Program website. http://pesticides.montana.edu/reference/drift.html. Accessed May 10, 2017.
4Enz J, Hofman V, Thorstenson A. Air Temperature Inversions — Causes, Characteristics and Potential Effects on Pesticide Spray Drift. North Dakota State University Extension Service website. https://www.ag.ndsu.edu/pubs/plantsci/pests/ae1705.pdf. Published April 2014. Accessed May 12, 2017.
