Los aceites minerales pueden ser una alternativa al uso de acaricidas para el control de araña roja

Los aceites minerales pueden ser una alternativa muy interesante a los acaricidas para el control de la araña roja, Tetranychus urticae Koch, una plaga que actualmente está produciendo importantes daños en el cultivo de clementinas. Sin embargo, la información sobre la dosificación de estos productos y su eficacia sobre este fitófago es prácticamente inexistente. En este trabajo se evalúa en laboratorio la eficacia de cuatro productos comerciales, a cinco concentraciones diferentes, sobre huevos, protoninfas y adultos de T. urticae. Así mismo, se estudia cómo se depositan estos productos, con el fin de determinar una posible relación entre los parámetros que describen la deposición (recubrimiento, tamaño y densidad de los impactos) y la eficacia acaricida. El producto que produjo mayor área media de las deposiciones fue también el más eficaz para controlar a la araña roja en todos los estadios y con una menor concentración de producto comercial, alcanzando niveles de eficacia de 90-100 %. Los demás aceites consiguieron eficacias elevadas a partir de concentraciones al 1,5 -2,0 %. También se observó que al aumentar la concentración de producto comercial en el caldo, se incrementó el recubrimiento y el área media de los impactos. Los aceites minerales han mostrado un gran potencial para controlar la araña roja en condiciones de laboratorio. El siguiente paso será determinar su eficacia en condiciones de campoMineral oils could be an alternative to acaricides for the control of the red spider mite, Tetranychus urticae, which causes major damage to clementine crops. However, the information on the appropriate dosage of these products and their effectiveness on this pest is practically non-existent. The effectiveness of four commercial mineral oil products (containing 81.49-85% oil) at 5 different concentrations (0.5 -2.0%) was evaluated in a laboratory study using eggs, protonymphs and adults of T. urticae. The study also investigated the deposition of the products to determine whether there was a possible relationship between deposition parameters (coating, size and density) and acaricidal efficacy. The product with the highest average deposition area was also the most effective in mite control at all stages of development, and reached 90-100% efficacy at a low concentration of product. The other 3 oils were also highly efficient at concentrations of 1.5-2%. Increasing concentration of the commercial product increased both coating and average area of impact. Mineral oils have proved to have a huge potential for the control or the red spider mite under laboratory conditions. The next step will be evaluating its efficacy under field conditions

Seeking the reuse of effluents and sludge from conventional wastewater treatment plants: Analysis of the presence of intestinal protozoa and nematode eggs

Some of the microorganisms present in urban wastewater, which include intestinal protozoa and nematodes, can be pathogenic. Their (oo)cyst and egg transmissible stages are very resistant to environmental stresses and disinfectants and they are therefore difficult to remove. Thus, they can constitute a health risk if water or sludge obtained in the purification of wastewater is reused for agricultural purposes. In this context, the presence of intestinal protozoa and nematodes were studied in influents, effluents and sludge from five wastewater treatment plants (WWTPs) in the north of Spain by optical microscopy and PCR techniques. The removal efficiency of different wastewater treatments was also compared. The presence of protozoa has increased among the population discharging waste to WWTPs in recent years. Cryptosporidium spp., Giardia duodenalis, Entamoeba spp. and nematodes were detected in all of the WWTPs. Indeed, this is the first report of Entamoeba histolytica and Entamoeba moshkovskii in Spanish WWTPs. The water treatments studied showed different removal efficiencies for each species of intestinal protozoa, with the aerated lagoons providing the best results. (Oo)cysts were also detected in sludge even after aerobic digestion and dehydration. To avoid risks, (oo)cyst viability should be analysed whenever the sludge is to be used as a fertilizer. This study reinforces the necessity of establishing legal limits on the presence of protozoa in WWTP effluents and sludges, especially if reuse is planned. Further studies are necessary for a better understanding of the presence and behaviour of intestinal parasites

Effect of spray volume of two organophosphate pesticides on coverage and on mortality of California red scale Aonidiella aurantii (Maskell)

A trial under laboratory conditions was carried out to study the possibility of decreasing the delivered dose of organophosphate insecticides without affecting their efficacy against California red scale (CRS). Aonidiella aurantii (Maskell), by reducing the volume of water used whilst maintaining the concentration of pesticide. In order to establish an optimal application volume, the coverage and the efficacy against different stages of development of CRS of two commercial organophosphate pesticides (chlorpyrifos 750 g kg(-1) WG [Dursban (R) 75 WG] and chlorpyrifos-methyl 224 g l(-1) EC [Reldan (R) E]) at four volumes of water (1, 2, 3 and 4 ml) were compared. Results showed that in general Chlorpyrifos-methyl-based product (CMBP) provided greater coverage and impact size, but did not achieve the highest efficacy. The minimum-deposited volume (1.01 mu l/cm(2)) produced 11% coverage with Chlorpyrifos-based product (CBP) and 22% with CMBP, reaching the highest efficacies (around 89-95%) against the youngest stages (N1 and N2 stages) with both products. To attain similar efficacy with males (prepupal and pupa stages), twice the volume (2.03 mu l/cm(2)) of the CBP was required, producing 28% coverage. The CMBP required higher deposited volumes (3.41 mu l/cm(2)) and higher coverage (51%). The maximum efficacy in the control of adult females (third instar and gravid female stages) was 70% with both pesticides. This level was attained with 3.41 mu l/cm(2) of CBP (36% coverage) and 4.72 mu l/cm(2) of CMBP (62% coverage). The research shows that greater coverage does not result in greater efficacy, so it would be possible to reduce the spray volume in field conditions. Further research will be carried out in order to check these results under real field conditions

Evaluation of a Citrus Mobile Platform Using a Wireless Impact Recording Device

Manual citrus harvesting is an expensive operation that represents between 25-40% of the total production costs. A mobile platform prototype to assist in the harvesting of citrus fruits designed by the IVIA (Spain) has been tested in order to reduce fruit damages. The mobile platform is fitted with conveyor systems. The multilevel platform can accommodate 4 to 8 workers who pick the fruit and place it on a conveyor belt. The picked fruit is transported to a central conveyor belt on which the fruit is transported to the in-line sorting system that classifies the fruit in two categories using a computer vision system and directs the fruit to one of the two different binfillers. During this process the fruits are subjected to mechanical stress causing physical injuries, including skin punctures, pulp and cell rupture. An impact recording device was used to evaluate damage produced to citrus fruits. The critical points at which damage occurs were determined, and the damage levels assessed. The highest damage level was produced from the bin-fillers to the bins. Seven different shocking absorbing materials were tested in order to reduce fruit damage. Five of the seven tested materials were capable to reduce the recorded impact