Weather conditions and sprayer operating parameters influence spray quality. Unmanned aerial vehicles are considered a modern, useful, and very efficient technological tool in the application of pesticides, as they carry out punctual spraying, and reduce environmental and public health problems. The objective of this study was to characterize the spraying quality carried out with an unmanned aerial vehicle as a function of flight height and target position in a coffee plantation in a mountainous region. Three flight heights (2.5, 3.0, and 4.0 m) were used, and the targets were placed at the top and bottom of the plant. For each plant, six water sensitive papers were placed on top of the plant and six were placed at the bottom. CIR 1.5 software was applied to determine the coverage percentage, drop density, volume median diameter, volumetric diameter corresponding to 10 and 90%, numerical median diameter, and relative amplitude. The results showed that the flight height only influenced the parameters of the volumetric diameter corresponding to 10% of the volume, numerical median diameter, and coverage percentage. The target position on the canopy influenced all the evaluated spraying parameters. In mountainous coffee plantations, the spraying system using unmanned aerial vehicle spraying is more efficient for the lower part of the plant.

Given the insecticidal potential of eugenol as a fumigant, this work aimed to determine the diffusion coefficient of eugenol emanating from a pure standard solution (99%), as well as from clove essential oil (Eugenia caryophillata Thunb. (Myrtaceae)) through rice grain; to chemically analyse the volatile composition of commercially available eugenol and clove essential oil; and to evaluate the mortality of Sitophilus zeamais Motschulsky (Coleoptera: curculionidae) after exposure to eugenol inside a test chamber filled with rice. The solid phase microextraction method of extracting and quantifying eugenol by gas chromatography presented a good analytical response for the quantification of the analyte. There was no significant difference between the diffusion coefficient of eugenol diffusing from pure eugenol or from clove essential oil. The diffusion coefficient of eugenol through rice with the conditions herein adopted is 1.09 × 10⁻³ cm² s⁻¹. The characterization of clove essential oil confirmed the presence of eugenol as its major component (74.25%). A difference was observed in the composition of the distinct phases evaluated. The exposure of adult S. zeamais to diffused eugenol from pure eugenol over seven days resulted in significantly higher mortality rates (~37%) than eugenol diffused from clove essential oil (~11%). No differences in mortality rates were observed in individuals placed at different positions inside the test chamber during eugenol fumigation.

This study aimed to characterize ozone gas (O₃) decomposition kinetics when injected at low pressure for controlling Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and its effect on popcorn kernel quality. The ozonation of the kernels was conducted in a 70-L hypobaric chamber, using samples of 5.0 kg of grains packaged in woven polypropylene bags. Firstly, the internal pressure of the chamber was reduced to 250 hPa, and ozone was injected at concentrations of 5.0, 6.7, 8.5, and 13.0 mg L⁻¹ until reaching a pressure of 940 hPa. The ozone concentration decay inside both the chamber and package was continuously monitored. The quality parameters assessed included the expansion volume, moisture content, electrical conductivity, and color of the popcorn kernels. The decomposition kinetics followed a first-order model in all concentrations studied. The values of decomposition rate constant (k) ranged from 0.030 to 0.014 min⁻¹, inside the package, and from 0.030 to 0.015 min⁻¹, inside the chamber. The ozone half-lives ranged from 22.7 and 49.8 min, inside the package, and from 20.6 and 46.5 min, inside the chamber. Ozone applied in a low-pressure system at 13.0 mg L⁻¹ controlled 94.45% of the S. zeamais insects in the grain mass. The injection of ozone gas at low pressure did not change the expansion volume, moisture content, and electrical conductivity of the popcorn kernels.