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The current study, performed in Castilla-La Mancha (Spain) in 2003–04, reports the growth, nutrition, tolerance to transplanting stress, and resistance to Verticillium dahliae of olive plantlets (Olea europaea L.) inoculated with different arbuscular mycorrhizal (AM) fungi (Glomus mosseae, G. intraradices and G. claroideum). Inoculated plants tolerated the stress of transplanting better than non-inoculated plants. Compared with controls, plantlets inoculated with any of these three Glomus species grew taller, had more and longer shoots, and showed higher plant N, P and K concentrations. However, colonization seemed to have no influence on resistance to V. dahliae.

The aim of the present work was to investigate the use of low and medium temperature active solar energy systems for the disinfestation of greenhouse soils. Four flat plate solar collectors (low-temperature solar thermal energy devices) and six parabolic trough concentrators (medium-temperature solar thermal energy devices) were used to heat water, which, via a buried heat exchange system, was used to heat the soil of greenhouse plots. These treatments were compared to no solar (control) and solarized (using a 50 µm-thick transparent polyethylene sheet) plots. Experiments performed in the summers of 2004 and 2005 showed that: 1) the temperatures reached and the energy accumulated in the soil -and therefore the disinfestation capacity -were greater with either of the active solar treatments (40-60ºC and 10.222.438-18.102.054 J, respectively) than with solarization (< 40ºC and 6.628.760 J, respectively) and 2) the temperatures reached using the parabolic trough concentrators (50 -60ºC) were higher than those achieved with the flat plate solar collectors (40-50ºC). The soil temperatures reached suggest these systems could be used to disinfest greenhouse soils.Additional key words: soil heating, soil treatment, solarization. Resumen Desinfestación de suelos de invernadero con colectores solares planos y concentradores cilíndrico-parabólicosEl objetivo de este trabajo fue investigar el uso de sistemas de energía solar activa de baja y media temperatura en la desinfestación de suelos de invernadero. Se usaron cuatro paneles solares planos y seis concentradores cilíndrico-parabólicos para calentar agua, la cual, a través de un intercambiador de calor enterrado, aumentó la temperatura del suelo de los bancales de un invernadero. Estos tratamientos se compararon con un bancal testigo y otro solarizado con una lámina de polietileno transparente de 50 µm. Los resultados de los ensayos realizados durante los veranos de 2004 y 2005 demuestran que: 1) las temperaturas alcanzadas y la energía acumulada en el suelo y, por tanto, la capacidad de desinfestación del sistema como consecuencia de los tratamientos solares activos (40-60ºC y 10.222.438-18.102.054 J, respectivamente) fueron superiores a las del suelo sometido a solarización (< 40ºC y 6.628.760 J, respectivamente) y 2) las temperaturas alcanzadas usando concentradores cilíndrico-parabólicos (50-60ºC) fueron superiores a las obtenidas con paneles solares planos (40-50ºC). Las temperaturas obtenidas en el suelo sugieren que estos sistemas pueden usarse eficientemente para la desinfestación de suelos de invernadero.Palabras clave adicionales: calentamiento del suelo, solarización, tratamiento del suelo.Abbreviations used: LDR (light-dependent resistors).

The re-use of propagation trays in nursery greenhouses is one of the main ways in which fusarium wilt is spread in melon crops (Cucumis melo). The causal agent of the disease is the fungus Fusarium oxysporum f. sp. melonis. This paper reports that exposing these seed trays to the energy produced by a prototype microwave oven during the commercial production of melon plantlets can prevent the spread of this pathogen with only a very small increase in production costs.