ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Parasitoid survey of California red scale ('Aonidiella auratii') in Citrus groves in andalucía (South Spain)
No full textCalifornia Red Scale (CRS) is one of the most important citrus pests all around the world. In the last years this pest has considerably increased its negative effects in the citrus industry of Andalusia. This pest owns a relatively rich complex of natural enemies, such as parasitoids which in certain parts of the world are successfully used in inoculative releases to control this pest. However, no information is available about the parasitoid complex in Andalusia. For this reason, we have sampled citrus orchards in four Andalusian provinces (Huelva, Cádiz,
Málaga and Almería) from March 2005 to May 2007, on a 45 days basis. Infested leaves, twigs and fruits were taken to the laboratory, where 100 scales per plant substrate were
observed under microscope binocular. We have detected three Aphelinidae (Hymenoptera) species: Aphytis melinus DeBach, Aphytis sp. (group lingnanensis) and Encarsia sp. The former was the most common, being the second less abundant. Encarsia sp. was extremely rare. The percentage of Aphytis parasitism was higher on females than on males. The parasitism was higher on leaves than fruits and twigs
Bioactive compounds in different citrus varieties. Discrimination among cultivars
No full textCultivars of Clementine mandarin (Arrufatina, Clemenpons, Clemenules, Fino, Hernandina Loretina, Marisol, Crogrande, Oronules and Oroval), Satsume mandarin (Avasa Pri-10, Avasa Pri-19, Ckitsu and Owari), Hybrid mandarin (Fortune, Ortanique and Nova), Navel orange (Fukumoto, Lanelate, Navelate, Navelina, Navel Foyos, Newhall and Powell), Common orange (Salustiana and Valencia Late) and Pigmented orange (Sanguinelli) groups have been analysed for its content in narirutin, hesperidin and total vitamin C. Sweet orange groups presented the higher concentration in flavonoids and total vitamin C. The influence of variety on the content of bioactive constituents and its contribution to taxonomy at the varietal level is studied. (C) 2008 Elsevier Inc. All rights reserved
ACTA HORTICULTURAE
No full textSpot real-time RT-PCR is a method for detection of Plum pox virus using conventional ELISA plant crude extracts immobilised on paper without the need of RNA extraction. The method was validated on different prunus field samples collected in winter and springtime. Seventy-nine percent of accuracy was obtained on winter samples and 97% in samples collected in spring. The sensitivity of spot real-time RT-PCR technique was compared with those obtained by DASI-ELISA, Co-PCR and conventional real-time RT-PCR using RNA as template. Spot real-time RT-PCR resulted 100-times more sensitive than DASI-ELISA and 10-times more sensitive than Co-PCR, although conventional real-time PCR was the most sensitive method for PPV detection. Joined to these advantages, spot real-time RT-PCR permits the storage of immobilised samples on paper at room temperature or frozen for long periods without decreasing the sensitivity of detection
Automatic correction of the effects of the light source on spherical objects. An application to the analysis of hyperspectral images of citrus fruits
No full textThis study proposes a method for correcting the adverse effects produced by the curvature of spherical objects in acquiring images with a computer vision system. Its suitability has been illustrated in a specific case of citrus fruits. The images of this kind of fruit are darker in areas nearer the edge than in the centre, and this makes them more difficult to analyse. This methodology considers the fruit as being a Lambertian ellipsoidal surface and produces a 3D model of the fruit. By doing it becomes possible to calculate the part of the radiation that should really reach the camera and to make the intensity of the radiation uniform over the whole of the fruit surface captured by the camera, no matter what region is being sampled. Some tests have been carried out in order to prove that using the proposed correction methodology the reflectance in all the surface of the fruit is similar, minimising the differences from the central area to the peripheral areas. The methodology presented here has been tested using a hyperspectral computer vision system based on tunable liquid crystal filters and it has proved to be effective for minimising the adverse side effects produced by the curvature of the fruit on the intensity of the radiation captured by the camera. The experiments show that applying our method homogenises the grey level of the pixels belonging to the same class, regardless of the region of the fruit surface they are from; standard deviation is also reduced, which facilitates subsequent classification tasks. (c) 2007 Elsevier Ltd. All rights reserved
Development of an immunosensor based on the measurement of fluorescence
No full textConsumers concern about the presence of pesticides in food is increasing. However current techniques for detecting pesticide residues in olive oil are very expensive and slow, which make them difficult to apply in commercial conditions. For this reason, the Instituto Valenciano de Investigaciones Agrarias (IVIA) and Universidad Politecnica de Valencia (UPV) have decided to develop an immunosensor as an alternative, fast and cheap method to measure the concentration of some pesticides in olive oil. This work shows the developed transducer by IVIA based on a photovoltaic sensor that transforms the fluorescent radiation to an electrical signal. The immunosensor is based on an immunologic reaction which causes fluorescence on the sample. The intensity of the fluorescence is related with the concentration of marked antibodies. The performed tests with two types of immunoassays and fluorescent markers (FITC and ELF97) have demonstrated the robustness and reliability of the developed transducer. The immunosensor is able to discriminate different concentrations of marked antibodies. This study has demonstrated the possibility of applying this immunosensor to detect chemical residues from pesticide treatments in olive oil samples. These results validate the sensor for future commercial applications. (c) 2007 Elsevier B.V. All rights reserved
Citrus leafminer 'Phyllocnistis citrella' (Lepidoptera: Gracilariidae) and its parasitoids: Ten years after the implementation of Classical Biological Control in Spain
No full textThe citrus leafminer Phyllocnistis citrella is a pest which originates from eastern and southern Asia and posed a serious threat to the citrus industry of the Mediterranean region upon its introduction in Spain in 1993 and its subsequent spread. Today, fourteen years after the
introduction of the pest and the following implementation of a Classical Biological Control Programme comprising the introduction of six exotic parasitoid species (Ageniaspis citricola, Quadrastichus sp., Semielacher petiolatus, Galeopsomyia fausta, Cirrospilus ingenuus and
Citrostichus phyllocnistoides) for the control of the pest, the citrus leafminer does not cause damage of economic importance on mature trees whereas a new balance of the parasitoid complex-pest system has established in the area of release. Monitoring of the incidence and quantification of the impact of both exotic and indigenous parasitoids and predators on the control of the citrus leafminer in mandarin orchards at three different locations in Eastern Spain showed that the exotic parasitoid Citrostichus phyllocnistoides is the predominant species, holding the 99.42% of the total in the survey. Indigenous parasitoid species represented minor percentages of the total: Pnigalio spp. (0.33%), Cirrospilus brevis (0.06%),
Sympiesis gregori (0.06%), Pteromalidae species (0.11%) and Diglyphus sp. (0.03%). The results provide insights into the interactions between the exotic and the indigenous natural enemies of the citrus leafminer and will contribute on the evaluation of the Classical Biological Control Programme
Morphometric characterization of sharpsnout sea bream (Diplodus puntazzo) and gilthead sea bream (Sparus aurata) spermatozoa using computer-assisted spermatozoa analysis (ASMA)
No full textAs part of a larger study on sperm quality and cryopreservation methods, the present study characterized the head morphometry of sharpsnout sea bream (Diplodus puntazzo) and gilthead sea bream (Sparus aurata) spermatozoa, using both scanning electron microscopy (SEM) and computer-assisted morphology analysis (ASMA). The latter method has been used rarely in fish and this is its first application on sharpsnout sea bream and gilthead sea bream spermatozoa. Results obtained using SEM are expensive and time-consuming, while ASMA provides a faster and automated evaluation of morphometric parameters of spermatozoa head. For sharpsnout sea bream spermatozoa, similar head measurement values were obtained using both ASMA and SEM, having a mean standard error length, of 2.57 +/- 0.01 mu m vs 2.54 +/- 0.02 mu m, width of 2.22 +/- 0.02 mu m vs 2.26 +/- 0.04 mu m, surface area of 4.44 +/- 0.02 mu m(2) vs 4.50 +/- 0.04 mu m(2) and perimeter of 7.70 +/- 0.02 mu m vs 7.73 +/- 0.04 mu m using ASMA and SEM, respectively. Although gilthead sea bream spermatozoa, were found to be smaller than those of sharpsnout sea bream,,spermatozoal head morphometry parameters were also found to be similar regardless of evaluation method, having a mean head length of 1.97 +/- 0.01 mu m vs 1.94 +/- 0.02 mu m, head width of 1.80 +/- 0.01 mu m vs 1.78 +/- 0.02 mu m, surface area of 3.16 +/- 0.03 mu m(2) vs 3.18 +/- 0.06 mu m(2) and perimeter of 6.52 +/- 0.04 mu m vs 6.56 0.08 mu m using ASMA and SEM, respectively. The results demonstrate that ASMA can be considered as a reliable technique for spermatozoal morphology analysis, and can be a useful tool for studies on fish spermatozoa, providing quick and objective results
Resultados preliminares de un estudio de caracterización de purines de porcino obtenido en fosa bajo condiciones mediterráneas
Get PDFEl conocimiento de la composición del purín recién excretado y en distintos momentos del ciclo
productivo del animal es importante, ya que permite conocer de una manera más precisa la evolución
que experimenta éste con el tiempo. Esto posibilitaría adecuar las estrategias de gestión y tratamiento
del mismo desde una perspectiva temporal a cada tipo de explotación. El purín contiene una gran
cantidad de flora bacteriana que lo degrada en función de su composición, de la duración del
almacenamiento y de las condiciones ambientales. Existe bastante información sobre la composición
de purines en balsa, sin embargo apenas existen datos sobre éstos en fosa. Es por ello que para
identificar tanto la variabilidad en función del tipo de animal como sus características en el tiempo es
interesante disponer de información obtenida en fosa. El objetivo de este trabajo es presentar los
primeros resultados de composición del purín de cerdos en granjas de la Comunidad Valenciana para
estudiar la variabilidad existente en función del tipo de animal y del tiempo de almacenamiento. Para
ello se tomaron 36 muestras en fosa, en varias explotaciones según la orientación productiva,
analizándose materia seca (MS), sólidos volátiles (SV), cenizas (ASH), pH, nitrógeno total (NT),
nitrógeno amoniacal (NH4), conductividad eléctrica (CE) y demanda biológica de oxígeno (DBO).
Asimismo se ha obtenido un perfil de ácidos grasos (AGV) para cada tipo de purín. De los resultados
obtenidos, se observa una importante variabilidad según la categoría animal, apreciándose en cebo
mayores contenidos en MS, SV y NH4. Finalmente, también se ha encontrado una elevada
correlación entre la conductividad eléctrica y el nitrógeno total excretado (R2 = 0,76), lo que podría
utilizarse como un “test rápido” de determinación de la composición de purín en campo
Modalidades productivas en el pimiento de invernadero y su incidencia en la comercialización
Get PDFSe comenta, en principio, la situación económica del pimiento y cual es su posición
competitiva. Actualmente la producción y comercialización de pimiento se encuentran
muy condicionadas en aspectos económicos, medioambientales, y de la calidad y
seguridad alimentaria, que se pueden sintetizar en: Unos costes de producción elevados;
los mercados se encuentran muy abastecidos, con riesgo de saturación y descenso de
los precios; dominio de la gran distribución en la comercialización; Política Agraria
Comunitaria (PAC) a favor del medioambiente y de la biodiversidad; sensibilización
de los consumidores por la sanidad de los productos y obligación de cumplir con la
trazabilidad.
Aunque España ha competido favorablemente con otros países europeos, en las
producciones hortofrutícolas de invernadero, deberá en el futuro tener en cuenta a los
países mediterráneos, más aún, después del Acuerdo Euromediterráneo.
En el trabajo se analizan las características de la producción de pimiento en invernadero,
centradas en el cultivo en sustrato, la producción integrada y la producción ecológica.
Una vez efectuada la valoración económica de cada modalidad productiva, se establecen
una serie de consideraciones sobre la incidencia de cada una de ellas en la
comercialización