Calibrating Backpack Sprayers
Hand-held and backpack sprayers are inexpensive tools used to apply pesticides on small acreages to protect them from weeds, brush, trees and vines. Effective vegetation management depends on applying the proper amount of herbicide, and this can only be done if the spray equipment is calibrated accurately for the desired rate.
There are a number of techniques for using a backpack sprayer when spraying an area or plot. Hold the nozzle tip steady at a suitable height above the target surface, usually within a range of 14 to 18 inches. Or, swing the wand back and forth in a pendulum motion as you walk. With either technique, it is essential that you achieve uniform coverage of the treatment site. Use the same pressure, speed and technique in the application that was used to calibrate the herbicide.
See Virginia Tech Bulletin Number 456-502 for specific calibration equations or the National Science Foundation Center for Integrated Pest Management (CIPM) for more calibration tips.
See Techline article on Backpack and Spot Treatment Calibration Guidelines.
Video: Calibration
Calibrating spray equipment before applying herbicides offers numerous benefits. This video goes over calibration techniques, as well as important points to remember when calibrating spray equipment.
Video: Equipment for Low-Volume Basal
This video reviews the proper equipment needed for a low-volume basal application, which can be very effective for selective control of unwanted trees..
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Tank-mixing Tips
Applicators tend to mix adjuvants, drift control agents, surfactants and/or dye with herbicides to increase efficacy and accuracy when making herbicide applications. However, the wrong combination can result in clogged nozzles, scum and precipitates in the tank, and can even damage the area you are treating. Avoid incompatibility, damage to desirable vegetation and other negative scenarios by following a few basic guidelines:
- Incompatibility occurs when one or more components of the mix create a chemical reaction, reducing the effectiveness of one or all of the herbicide components. A jar test is the most practical method to visually check for incompatibility. Fill a quart jar with the correct ratio of the materials in the mix. This should show you if your mixture is compatible.
- Start with a clean tank. If a tank is not clean, the jar test won’t help. Vigorously agitate the tank contents while mixing and applying the products. If you take a break, leave the agitator running.
- Even with proper agitation, never start spraying on the desired target. Apply the herbicide mixture to a small test area before broadcasting.
- Always follow the correct filling order for products.
- Be aware of all mixing requirements and procedures indicated on the product labels.
- Keep containers below eye level when opening and pouring.
- Keep fill hoses above water level in the spray tank to prevent back-siphoning.
- Be aware of wind direction before pouring to minimize exposure downwind.
- Never use your hands to stir the mixture or retrieve an item dropped into the tank.
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Training for Continuum™
Continuum™ Prescription Control & Container Management System is a total product delivery solution that offers multiple benefits to vegetation management professionals. The Continuum system is a closed-loop delivery solution that eliminates container rinsing and disposal, and reduces container storage and handling requirements, labor costs and accidental exposure to workers. Developed exclusively by Dow AgroSciences, the Continuum System allows vegetation management professionals to order standard or custom tank mixes, straight product or diluted concentrate.
Back to Application Tips and Training
Other product-related literature:
Continuum™ Prescription Control & Container Management System Brochure
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