Evaluation of spray deposition in potatoes using various spray delivery systems

Abstract

The tomatopotato 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 airassisted rotary atomizer and a highvolume airassist 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

Comparison of spray dose measured on leaf surfaces with spray coverage estimated from Kromekote paper

“…For instance, if the AI is systemic the coverage is likely a nonissue; or if the weed species are shorter than the crop, electrostatics will prohibit the herbicide from reaching the actual target. The deposition of dye throughout the canopy was consistent with the findings of Roten et al (2013) where similar patterns coverage were observed between all sprayers ( Table 2). The previous K-card work (Roten et al 2013) observed less coverage than expected with the DropSpray® system.…”

“…The deposition of dye throughout the canopy was consistent with the findings of Roten et al (2013) where similar patterns coverage were observed between all sprayers ( Table 2). The previous K-card work (Roten et al 2013) observed less coverage than expected with the DropSpray® system. The two most notable differences between the two datasets are that (1) the conventional boom applied 389% AI to the upper most canopy and leaf side, which is statistically different (P<0.05) from all other treatments and (2) the Proptec™ atomiser deposited greater amounts of AI on the lower leaf side of the upper canopy than would have been expected from the 7.6% coverage indicated in the previous study.…”

“…A full description of the experimental methods for the K-card study can be found in Roten et al (2013). In short, K-cards were horizontally placed at the top, middle and lower canopy; each card was marked to specify the upper and lower sides.…”

“…Tomato potato psyllid control and prevention has been reported to cost approximately $28 million per annum (Kale 2011), which is largely due to the frequent applications of pesticide. Previous work (Roten et al 2013) evaluated six spray delivery systems using Kromekote® (K-cards) to collect qualitative data on spray coverage at designated heights adjacent to leaves to further assess deposition throughout the potato canopy. The aim was to examine the three-dimensional deposition on both sides of the K-card in the top, middle and bottom canopy strata.…”

Chemical Control of Asian Soybean Rust as a Function of Cultivar, Row Spacing and Spray Bar Support Systems

“…The utilization of the Dropleg ® bar support system aims at the enhancement of mixture accessibility at sites, such as the bottom part of the plant. Still considering that the system operates inside the canopy, a better drift control driven by wind action exists, as well as the possibility of varying the ratio between the amount of mixture sprayed through the Dropleg ® system and the conventional spray bar, as both can be adjusted according to the growth of the crop (Roten et al, 2013;Rüegg & Total, 2013).…”