Evaluation of spray deposition in potatoes using various spray delivery systems

The tomato-potato psyllid incurs high control costs through intensive spraying and other treatments. A field study was conducted in March 2012 in Pukekohe, New Zealand, to evaluate the pesticide deposition potential of five different spray delivery systems. The treatments included a conventional boom, a canopy submerged drop sprayer combination, a pneumatic electrostatic spraying system, an air-assisted rotary atomizer, and a high-volume air-assist boom. Each system was calibrated for appropriate spray volume rates between 167 and 400 litres/ha. Rhodamine WT fluorescent dye used as a tracer was sampled on folded Kromekote® sampling cards oriented flat and horizontally above, central to, and below the canopy. Spray coverage rates were quantified at designated heights adjacent to leaves to assess deposition throughout the potato canopy. All treatments that consisted of one or more novel technologies consistently gave higher coverage to the underside of the potato leaves than with the conventional boom