Deposition and Coverage of Soybean Leaf Surfaces by Sprays Applied Using Different Assisted Boom Sprayer Systems

Abstract

Maintaining homogeneity in the distribution of fungicidal sprays applied throughout the plant, minimizing the variation between the upper and lower third of the plant, is one of the main challenges for application technologies with regard to soybean crops. To increase the deposition and leaf coverage of sprayed compounds, especially in the middle and lower thirds of the plant, we developed and tested alternative assisted boom sprayer systems. In this study, three assisted boom sprayer systems (Vortex ® , Dropleg ® , and chain curtain) were evaluated, in addition to the conventional system, in terms of the deposition and coverage of the leaf surface they achieved in the upper, middle, and lower thirds of plants using the fluorescent tracer Helios SC 500™. The assisted boom sprayer systems allowed the sprayed mixture to be better distributed throughout the plant. With the conventional spray system (without assitance), the deposition in the upper third was approximately 26 times higher than that in the lower third, whereas with the use of the assisted boom sprayer systems, the difference in deposition between these thirds was 11 times higher. Among the evaluated systems, the Dropleg ® system presented the lowest depositional variation, which was only 5.5 times higher in the upper than in the lower third, because of the increased deposition achieved in the lower third of the plant. Leaf coverage varied from 41% to 81% in the upper third, from 24% to 43% in the middle third, and from 4% to 13% in the lower third of the plant. Using the conventional spray system, the leaf surface coverage was approximately 13 times higher in the upper third than in the lower third of the plant, whereas with the use of the assisted boom sprayer systems, especially the Dropleg ® system, this variation was reduced by 73%, and the coverage of the upper and lower thirds only differed by 3.5 times. Indeed, the Dropleg ® system reached a leaf coverage of close to 13% in the lower third of the plant. The use of assisted boom sprayer systems improved the distribution of the mixture applied throughout the plant, reducing the differences among the thirds of the plant both in the levels of deposition and coverage of the leaf surfaces. The Dropleg ® system increased the deposition and leaf coverage in the lower third of the plant the most, facilitating better distribution of the mixture.

Vertical distribution of Bemisia tabaci on soybean and attractiveness of cultivars

“…This matches the vertical distribution of nymphs found in our study. Another implication is that a greater infestation by adults and nymphs of the upper third of the plant may facilitate the control of B. tabaci, as pesticides have greater coverage in the upper third (Hoffmann et al, 2019). In attractiveness bioassays conducted in the present study, the upper third of the plant was one of the most reliable predictors of a soybean cultivar's attractiveness to whiteflies, because the largest number of adults and degree of colonization by whitefly nymphs was recorded there.…”

The Influence of Wetting Agent and Type of Nozzle on Copper Hydroxide Deposit on Sugar Beet Leaves (Beta vulgaris L.)

“…For laboratory conditions, the CV of the transverse spray distribution measured on the paternator should be lower than 10% and ideally lower than 7%. Only such a distribution guarantees the good quality and efficiency of protection on the whole working surface of the sprayer booms [28]. It is interesting to analyze the behavior of the coefficient of variation (CV) of the transverse distribution of nozzles with the increase in the rate of pinole-based wetting agent.…”

“…Satellite images can be used for early detection of CLS in sugar beet [28]. Based on the obtained values and the analysis of the TGI vegetation index, the beginning of the infection with CLS on the sugar beet leaves was determined.…”

Multivariate Analysis Applied to the Ground Application of Pesticides in the Corn Crop

“…A similar effect was reported by Machado and Reynaldo [36] when evaluating the differences between aerial and ground applications. This difference can be mitigated depending on the equipment and technology used [37].…”