No abstract

Coffee production and marketing is one of the main global commercial activities, but crop yields depend on several factors, among which plant health. The objective of this study was to evaluate the efficiency of spray droplet deposition in coffee crops grown in a mountain region, associated to the efficacy of the control of fungal diseases. The application efficiency, using an unmanned aerial vehicle (UAV), and the efficacy of the products applied were tested. Water-sensitive paper tags were used to analyze the application efficiency; agronomic efficiency, vegetative vigor, yield, and physiological parameters were used to determine the fungicide efficacy. Droplet coverage in the upper canopy layer using a pneumatic sprayer (28.70%) was 4.11-fold higher than that found in the same layer for application using a UAV (6.98%) at the rate of 15 L ha−1. The highest droplet depositions by using a UAV were found for the rate of 15 L ha−1: 1.60, 1.04, and 0.43 µL cm−2 in the upper, middle, and lower layers, respectively; the deposition in the upper layer with application using a pneumatic sprayer was 42.67 µL cm−2, and therefore, a 26.7-fold higher deposition. The results denote that the control of fungal diseases through fungicide applications using a UAV is efficient for mountain coffee crops.

The efficiency of applications through spraying is connected to the capacity to minimize losses by endo-drift and exo-drift while ensuring adequate coverage and deposition on the target surface; the spray nozzles is the main factor connected to application quality. However, few researches focus on technology of application in black pepper crops. The objective of this work was to evaluate the coverage of droplets of simulated herbicide applications using different spray nozzles. The experiment was conducted in a commercial crop area of black pepper of the variety Bragantina, in a randomized block with a 2×2+1 factorial arrangement with four replications per treatment. The nozzles used were XR11002 VP, AI11002 VS, with and without protector (Chapéu de Napoleão) and an additional treatment using the manual backpack sprayer standard nozzle without protector. The results showed that, under these conditions, the nozzle AI11002 VS with protector resulted in adequate coverage and deposition of droplets between rows decreasing the risk of phytotoxicity to black pepper plants. The nozzle XR11002 VP presented higher coverage of droplets in the lower third of black pepper plants. The backpack sprayer standard nozzle resulted in the lowest coverage of droplets between rows.

No abstract

Papaya production and export is increasingly expanding in the world market due to the nutritional importance of the fruit. Phytosanitary issues, labor shortages, and unevenness in land-based costal and motorized applications compromise crops, the environment, and humankind. The purpose of this study was to evaluate the efficiency of droplet distribution using an unmanned aerial vehicle, with different application rates (12.0, 15.0, and 18.0 L ha−1) and spray nozzles (XR110015 and MGA015) in the upper (UL), middle (ML), and lower (LL) layers, and on papaya fruit clusters (BF). Water-sensitive paper labels and artificial targets were used to assess the efficiency. Coverage, density, droplet distribution, and droplet diameter were influenced by the application rates in the following order: 18.0 > 15.0 > 12.0 L ha−1, showing concentrated droplet distribution in the respective layers: UL > ML > LL > BF. The 18.0 L ha−1 rate increased the variables examined, and the droplet coverage on the UL using the XR110015 nozzle was 6.56 times greater than that found on the LL and BF. The MGA015 nozzle presented better results in the LL and BF in all variables analyzed. The UAVs were efficient in applying to the papaya crop and further studies should be carried out in order to confirm the efficacy of plant protection products applied using this technology.