The application of pesticides has been of concern for many years, particularly methods of reducing drift and improving deposition. There are many interrelated factors which affect spray application depending upon the target, the efficacy of the spray, the attitude of the operator, the standard of management, the weather etc.
In modern vineyards there are numerous row widths, varieties, plant spacing and variations in canopy shape and style. Canopy characteristics (height, width and density) also change as the growing season progresses.
Good disease and insect control is dependent upon the correct amount of pesticide being applied at the correct time. Incorrect application may result in pest resistance, poor pest or disease control, increase costs for the grower, and an increased risk of chemical contamination in the environment.
The operation of the sprayer often leaves much to be desired. Most growers know that there are three factors which affect application rate: forward speed, nozzle size and system pressure; but often overlook the factors which help get the spray onto the target: airflow, liquid flow, forward speed and canopy structure. Progress lies in the direction of a better understanding of the factors involved in getting the spray from the tank to the vines. Adjusting airflow and liquid flow to match the growing canopy as the season progresses is the key.
Paper presented at the “International Cool Climate Wine Symposium”, ICCWS, Brighton, England, 26-28 may 2016