The basic performance and field application test of newly developed flower thinning system for peach cultivation

We developed a pulsatory water spray gun system aimed at improving the efficiency of fruit setting management in peach cultivation and evaluated its feasibility for field application. In order to select the optimum water spray conditions and developmental stages of a flower for field applications, the influence of varying pressures of the power sprayer, nozzle diameters, and spray distances on flower and leaf bud thinning rate was investigated under four different developmental stages of flower such as bud sprouting, pink, balloon and flowering period using the water cut bearing branch of “Kawanakawase Hakuto” peach. The optimum conditions for the application of the pulsatory water spray gun were identified as a power sprayer pressure of 2 MPa at a nozzle diameter of 2 mm and spraying distance of 1 m in the ballooning and flowering stages. A flower bud thinning rate greater than 60 % and a leaf bud thinning rate lower than 7 % were observed under these conditions. In the field application test based on the selected conditions, the flower and leaf bud thinning rates were ideal for fruit production and showed higher fruit characteristics compared with fruits produced by a conventional fruit setting management method. In addition, the application of this system for flower thinning could considerably reduce the total work time compared with the conventional method. Hence, it is also expected that the newly developed system can be used for labor savings during fruit setting management in peach cultivation.