Calculations for the application of fungicides and insecticides to commercial orchards are often complicated and can be downright confusing. While these mathematical exercises may leave many scratching their heads, they are critical to the success of a spray program. Over-application of products may result in increased costs, phytotoxic effects, and/or negative environmental impacts, while under-application opens the door for disease, insect, and weed problems. Dr. Nicole Gauthier, UK Extension Plant Pathologist and Dr. Ric Bessin, UK Extension Entomologist, have developed the “Orchard Math 101: For Proper Spray Application” worksheet (Figure 1). This document assists growers with calculations for gallons-per-acre calculations, nozzle selection, and other components for spray coverage. The “Orchard Math 101” document is available online here. For additional assistance or information about pesticides, contact your local county extension office.
By Nicole Gauthier, Extension Plant Pathologist, and Kim Leonberger, Extension Associate