Techno-economic impacts of using a laser-guided variable-rate spraying system to retrofit conventional constant-rate sprayers

Specialty crops, such as apples, are vulnerable to insects and pathogens, and require higher pesticide input than row crops, a significant fraction of which is off-target loss, causing adverse environmental and socio-economic impacts. An advanced laser-guided variable-rate sprayer (VRS) could improve spray deposition uniformity and minimize pesticide waste, while maintaining efficacy against insects and pathogens. Despite these merits, retrofitting a conventional sprayer with laser-guided variable-rate spraying functions adds to its cost. Thus, the objective of this study was to analyze the techno-economics of a conventional pesticide sprayer retrofitted with VRS, in comparison to a conventional constant-rate sprayer (CRS) for pesticide application during apple production. A techno-economic model was developed for the apple orchards covering areas of 4 and 20 ha, which are common orchard sizes in the USA. The model incorporated cost for operation, equipment, fuel use and labor during pesticide application. The data were obtained from field tests in orchards in Ohio, USA in years 2016 and 2017, literature, and the original VRS development team at USDA-ARS and Ohio State University. The results indicated that VRS can reduce pesticide costs by 60-67%, pesticide application time by 27-32% and labor and fuel by 28% compared to CRS. For larger orchards, VRS also reduced equipment requirement. Compared to CRS, overall annual pesticide application cost savings by using VRS were between $1420 and $1750 ha(-1). The payback time for using VRS was estimated to be between 1.1 and 3.8 years for apple orchards between 4 and 20 ha, respectively, in Ohio.