In order to solve the problem of uniform surface treatment of bored areas of perennial plantations (treatment with herbicides) the graph-analytical method of examination of treatment quality (determination of untreated and treated area around the overlapped die) is proposed. To do this, you need to specify the diameter of the stamp of perennial planting, the overall size of the deflector in the form of a stylus, its position in the space relative to the diameter of the stamp of perennial planting, the size of the overlap zone when treating with herbicides in the gardens, the distance between the dies and the operating speed of the unit to determine the geometric and operating parameters of the sprayer. The whole stage of the working device (probe), when it is working in the nozzle zone is divided into 4 stages. Analysis of the graphical image of the stylus trajectory during movement around the stamp gives an idea of the surface treatment process with herbicides during spraying. In the first stage, part of the borehole zone is treated with overlap, while in the third stage, the untreated area around the die is left untreated. The dependencies of determining these areas depending on the geometric dimensions of the dies, their location in the gardens, the length and angle of the stylus and the operating speed of the unit are derived. According to the different trajectories of movement, in the process of influence of a stylus on a stamp there is a change of direction of an air-droplet stream, as a result of which the flow of a working liquid and accordingly the processed area changes. It is possible to determine the deviation of the actual rate of fluid flow from the specified rate at different points in the borehole area by calculating the areas treated with overlap and untreated. All obtained dependencies will serve for optimization of geometrical and mode parameters of the working device (feeler gauge) during its operation in the borehole zone.