BACKGROUND: Susceptible tomato cv. Durinta, ungrafted or grafted onto cv. Aligator resistant rootstock, both followed by the susceptible melon cv. Paloma, ungrafted or grafted onto Cucumis metuliferus BGV11135, and in the reverse order, were cultivated from 2015 to 2017 in the same plots in a plastic greenhouse, infested or not with Meloidogyne incognita. For each crop, soil nematode densities, galling index, number of eggs per plant and crop yield were determined. Virulence selection was evaluated in pot experiments. RESULTS:In the tomato-melon rotation, nematode densities increased progressively for the grafted tomato, being higher than for ungrafted plants at the end of the study; this was not the case in the melon-tomato rotation. Grafted crops yielded more than ungrafted crops in the infested plots. Virulence against the Mi1.2 gene was detected, but not against C. metuliferus. Reproduction of M. incognita on the resistant tomato was ∼ 120% that on the susceptible cultivar after the first grafted tomato crop, but this decreased to just 25% at the end of the experiment. CONCLUSION: Alternating different resistant plant species suppresses nematode population growth rate and yield losses.Although this strategy does not prevent virulence selection, the level was reduced.

Abstract:The global trend on energy integration and building efficiency is making both researchers and building developers look for technical solutions to use facade surfaces for energy harvesting. In this work, the assessment of the thermal performance of a double-skin facade (DSF) with a venetian blind-type of structure used as a solar thermal collector by means of computational fluid dynamics (CFD) is presented. A Venetian blind collector would allow for heat rejection/energy harvesting and exterior views simultaneously and can be easily integrated into the DSF aesthetical design. For the purposes of this study, the modeled facades (south, west, and east-oriented) were set to be located in Barcelona (Spain), where large solar gains are a constant condition throughout the year, and such large semi-transparent envelopes lead to interior over-heating in buildings, even during the winter. For the studied facades, both the reductions in radiative heat gains entering the building and the heat recovery in the Venetian blind collector were evaluated for a yearlong operation.

The effect of molasses alone or combined with Trichoderma asperellum T34 Biocontrol® was assessed on Meloidogyne reproduction, disease severity, and density and activity of soil microorganisms in pot and field experiments. Firstly, molasses application at 1 mL m−2 was assessed in four different textured soils. Secondly, molasses application at 5, 10, 20, and 40 mL m−2, alone or combined with T34, was assessed in pot and field experiments at 10 mL m−2 in two different textured soils. The application of 1 mL m−2 of molasses was effective in reducing nematode reproduction in the loam textured soil but not in sandy clay loam, sandy loam, or clay loam textured soils. Increasing molasses dosage reduced the tomato dry shoot and fresh root weights, producing phytotoxicity at 40 mL m−2. The disease severity and nematode reproduction were reduced between 23% and 65% and 49% and 99%, respectively. In the field experiment, molasses applied at 10 mL m−2 reduced the disease severity and the nematode reproduction in the loam textured soil. The soil microbial density and activity did not increase in sites where the nematode reproduction and the disease severity were reduced by molasses application, irrespective of T34.

The fluctuations in Meloidogyne densities and fungal egg parasitism were determined from February 2015 to July 2016 in four vegetable production sites conducted under organic production and two sides conducted under integrated standards. At each site, the soil nematode densities at transplanting and at the end of the crops, the galling index, the number of eggs in roots, and the percentage of fungal egg parasitism were determined, and the fungal species were identified. In addition, two pot experiments were conducted with soil taken from each site in February 2015 and 2016 to assess the fungal egg parasitism comparing non-sterile and sterile soil from each site. In field conditions, the nematode population densities in the soil decreased along the crop rotations. The maximum number of eggs per plant was recorded in the spring–summer crops. Egg parasitism ranged from 11.2 to 55% in the organic sites and from 0.8 to 16.5% in the integrated production sites. Pochonia chlamydosporia was the only fungal species isolated in five of the six sites. In both pot experiments, the number of eggs per plant was lower in non-sterile than in sterile soils, except for the M10.45 site, where fungal egg parasites were not recovered. P. chlamydosporia was the only fungal species isolated, ranging between 11 and 74%. Therefore, P. chlamidosporia was the most prevalent fungal species related to Meloidogyne suppression.