Evaluation of the Intelligent Sprayer System in peach production

Authors: BOATWRIGHT, HARRIET - Clemson University; Zhu, Heping; Clark, Adam; SCHNABEL, GUIDO - Clemson University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2020
Publication Date: 11/20/2020
Citation: Boatwright, H., Zhu, H., Clark, A.C., Schnabel, G. 2020. Evaluation of the Intelligent Sprayer System in peach production. Plant Disease. 104(12):3207-3212. https://doi.org/10.1094/PDIS-04-20-0696-RE.
DOI: https://doi.org/10.1094/PDIS-04-20-0696-RE

Interpretive Summary: Air-blast sprayers have been widely used for effective control of pests and diseases in peach orchards and other specialty crop production. However, their efficiency in material usage is very low. An intelligent spray control system was recently developed as a retrofit for the air-blast sprayers to revolutionize the modern pesticide application practices. With the retrofit, the sprayers can precisely discharge the amount of chemicals on targets and minimize off target sprays by taking into account the tree shape, canopy density, tree row space and travel speed. In this research, a standard air-blast sprayer retrofitted with the intelligent spray control system was investigated and compared with the conventional constant-rate application in peach orchards in South Carolina. The comparisons included pest and brown rot disease control, spray volume used per acre, and spray coverage and drift. Field tests demonstrated the intelligent spray system ensured pest and disease control efficacy in peach orchards, while significantly reducing spray drift and the amount of spray materials used. The reduction in spray volume up to 71% would be most significant when used on younger trees and on trees early in the season before tree canopy closed. These scientific evidences assured the sustainable benefits of using the new intelligent spray technology in commercial peach production.

Technical Abstract: Air-blast sprayers are routinely used to apply pesticides in commercial peach orchards, with growers using both conventional air-blast and ultrasonic sensor driven models. Even with advanced spray technologies, there are still concerns with the amount of chemicals used and lost to drift. Our study evaluated a LIDAR-based variable rate sprayer system in three experimental peach orchards for pest and brown rot disease control, spray volume output, spray coverage, and spray drift. A single 378 L airblast sprayer was used, the conventional air-blast and the Intelligent Sprayer (iSprayer) treatments. Treatments were started at the phenological stage of bloom and continued through final swell. The iSprayer treatment was as effective in controlling pests and brown rot disease as the conventional air-blast treatment. Compared to the conventional air-blast treatment, the iSprayer reduced the spray volume (liter/hectare) in cultivar PF23 by 71% at bloom, 62% at pit hardening and 55% at commercial maturity, respectively. For ‘Juneprince’ the spray volume reduction was 50% at bloom, 40% at pit hardening, and 13% at final swell, respectively. Spray drift was significantly (P<0.05) reduced only at bloom in the iSprayer treatment. Spray coverage was increased by 50.13% and 26.67% in the iSprayer treatment at bloom and pit hardening, respectively, but not at final swell. Our results show that the iSprayer maintained pest and disease control efficacy in peach orchards, while reducing spray volume and drift compared to the conventional air-blast treatment.