Protected horticulture production represents one of the most important agricultural businesses in Southern Europe. However, many problems related to the lack of mechanisation, intensive use of pesticides, and, in some cases, undesirable residues on food, have not been solved yet. In this context, application technology is a key factor for the improvement of the efficacy and efficiency of plant protection products. Spray guns and knapsack sprayers are the most common technologies that have been used for this purpose. However, several studies have demonstrated that, compared with spray guns, the use of vertical boom sprayers in greenhouses improves spray distribution and reduces labour costs and operator exposure. The main objective of this study was to evaluate the influence of air-assistance on spray application in conventional tomato greenhouses. For this purpose three different spray conceptions were evaluated; 1) a modified commercial handheld trolley sprayer with two air assistance concepts; 2) a self-propelled sprayer; and 3) an autonomous self-propelled sprayer with remote control. All the sprayers considered were evaluated in terms of absolute and normalised canopy deposition, uniformity of distribution, and losses to the ground. In addition, the vertical liquid and air velocity distributions of the sprayers were assessed and compared with the canopy profiles and spray depositions. Yellow tartrazine (E-102 yellow) was used as a tracer for deposition evaluation. The results indicated that increasing the air velocity does not increase the efficiency of a spray application. In general, the modified handheld trolley sprayer showed the best results in terms of deposition and uniformity of distribution, especially at the lowest air assistance rate. These results were confirmed with evaluation of the uniformity of the air and liquid distribution. (C) 2015 Elsevier Ltd. All rights reserved.
The relationship between the initial (Pi) and final (Pf) population densities of Meloidogyne javanica in response to increasing initial inoculum levels and the effect on yield in zucchini cv. Amalthee (Cucurbita pepo L.) was determined using a geometric series of 12 Pi from 0 to 51,200 eggs/100 cm(3) of soil in pot experiments in a greenhouse. The maximum multiplication rate was 425, and the equilibrium density was 701,951 eggs/100 cm(3) soil. The relative yield, represented as dry top weight, fit the Seinhorst damage function model and the minimum relative yield (m) was 0.82 and the tolerance limit (T) was 402 J2/100 cm3 soil. Regression analyses indicated a negative relationship between the Pi and the leaf chlorophyll content (LCC) 40, 50, 60, and 70 days post-inoculation. The Pi and LCC fit the Seinhorst damage-function model. Zucchini cv. Dyamant was planted in a plastic greenhouse with a range of M. javanica Pi from 0 to 861 J2/100 cm3 soil. The maximum multiplication rate of M. javanica under field conditions was 3093, and the equilibrium density was 1485 J2/100 cm(3) soil. The relationship between Pi and relative yield, represented as fruit weight, fit the Seinhorst damage function model (P <0.0001, R-2 = 0.78); m was 0.48, and T was 0.02 J2/100 cm(3) soil. (C) 2014 Elsevier Ltd. All rights reserved.
Gil, E.; Balsari, Paolo; Gallart, M.; Llorens, J.; Marucco, Paolo; Andersen, Per Gummer; Fabregas, F.; Llop, J. Crop protection Vol. 56, p. 58-68 DOI: 10.1016/j.cropro.2013.10.018 Data de publicació: 2014-02 Article en revista
This study's objective was to evaluate the functionality of an ad hoc test bench for spray drift measurement with boom sprayers, using it for evaluating different nozzles according to drift risk. The repeatability of results was evaluated by conducting similar tests at two different laboratories. Drift potential values (DPV) obtained showed an interesting effect of Venturi flat fan nozzles on drift reduction, in comparison with conventional flat fan nozzles (reference nozzle was XR 11003). Newly designed flat fan nozzles reduced the risk of drift. Reasonably relations between 10th-percentile, D[v,0.1], 50th-percentile or Volume Median Diameter, D[v,0.5], 90th-percentile, D[v,0.9], V100 and DPV were observed in all cases, with R2 values of 0.58, 0.65, 0.66 and 0.72, respectively. The lowest drift values were achieved with TTI and TD Spray Max nozzles; they were significantly lower than those obtained for IDK and AIXR ones. Results indicated that the drift test bench can be used as an alternative to the official standard procedure for drift measurements on boom sprayers (e.g. ISO 22866), as it is able to discriminate the influence of different boom settings (especially nozzle types) on drift. Further studies could be useful in order to prove that the classification of nozzles according to drift risk obtained using the test bench is comparable to the nozzle classifications obtained applying the ISO 22866 test method.
Reproduction of Meloidogyne arenaria and Meloidogyne javanica on 12 tomato rootstocks and cultivars was tested to determine their relative resistance levels in a greenhouse with a non-temperature controlled environment. The nematode accumulated 754 and 719 degree-days (basal temperature 10 degrees C) in Experiment 1 (Exp. 1) and Experiment 2 (Exp. 2), respectively, but heat accumulation occurred more rapidly in Exp. 1 (65 days post-inoculation, dpi) than in Exp. 2 (88 dpi). Soil temperatures above 28 degrees C were recorded for 31 days during the experimental period in Exp. I, and 20 days in Exp. 2. However, daily fluctuations in soil temperatures and intermittent peaks above 28 degrees C did not compromise the resistance provided by the Mi-1 gene, and thus rootstocks Morgan, King-Kong, and Unifort consistently expressed a high resistant phenotype to M. arenaria and M. javanica. In contrast, rootstocks Multifort and Maxifort expressed reduced resistance levels. The reproduction rate of M. javanica was significantly higher (P < 0.05) than that of M. arenaria on the resistant and susceptible genotypes except for on the susceptible Motril in Exp. 1.
Talavera, M.; Verdejo-Lucas, S.; Ornat, C.; Torres, J.; Vela, M.; Macias, F.; Cortada, L.; Arias, D.; Valero, J.; Sorribas, F. Crop protection Vol. 28, num. 8, p. 662-667 DOI: 10.1016/j.cropro.2009.03.015 Data de publicació: 2009-08 Article en revista