Multivariate Analysis Applied to Spray Deposition in Ground Application of Phytosanitary Products in Coffee Plants

Abstract

An adequate combination of factors involved in the technology used for phytosanitary product application contributes to an efficient spray deposition on the target. The objective of this study was to use multivariate analysis to characterize the magnitude of effects and the order of influence of three factors that interfere with the quality of phytosanitary product application in coffee plants. An entirely randomized design was adopted, with four repetitions, using a 2 × 2 × 3 factorial scheme, with two classes of droplets quality (fine and coarse), two application rates (250 and 400 L ha -1 ), and the use of adjuvants (with no adjuvant or with Fighter ® and Aureo ® adjuvants). The quality of the application was determined by jointly analyzing the spray deposition on three thirds of leaves, in their internal and external layers, the runoff to soil, coverage, droplet density, relative amplitude, and the volumetric median diameter. The results underwent analysis of variance (ANOVA) to measure the effect sizes (η 2 ). After testing the assumptions of multivariate analysis, clustering and principal component analyses were performed. The class of droplets was found to be the most influential factor in the quality of the phytosanitary product application (spray deposition and runoff to soil). When focusing on spray deposition on leaves, the second-most influential factor was the application rate and the relation between the application rate and the adjuvants. For the other variables, the second-most influential factor was the application rate.

Efficiency of Fungicide Application an Using an Unmanned Aerial Vehicle and Pneumatic Sprayer for Control of Hemileia vastatrix and Cercospora coffeicola in Mountain Coffee Crops

“…Regarding plant health protection, there were significant advances in the technological development of selectivity and efficacy of pesticides; however, the pesticide application technology connected to this development did not follow the same pace, and in the specific case of coffee crops, pesticide applications have usually been inefficient [5,6]. The pesticide application technology for coffee crops should be well managed to avoid losses of product to non-target areas; therefore, the target position, architecture of coffee plants, climate conditions, nozzle positioning, and regulation and calibration of sprayers should be considered [7,8].…”