Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.) (Coleoptera: Curculionidae)

Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Samples of DE were mined from DE-deposits in Slovenia, Greece, and Serbia. In addition, a commercially available DE formulation (SilicoSec^®) was used in the tests and served as a positive control. The bioassays were carried out at temperatures 20, 25, and 30°C, relative humidity levels of 55 and 75%, and at application rates of 100, 300, 500, and 900 ppm. Adult mortality was recorded after 7, 14, and 21 days of exposure. Prior to bioassays with S. oryzae, the geochemical composition of all DEs that were used in the tests was determined by whole rock ICP geochemical analyses. Silica (in the form of SiO₂ or opal-A) was the DE ingredient that was significantly correlated with efficacy in most of the bioassays. Some weak positive correlation was observed between S. oryzae mortality and MnO or CaO content. All significant correlations between mortality and Al₂O₃, Fe₂O_3, K₂O, TiO₂, Cr₂O₃, P₂O₅, and MgO content were negative, while correlation between Na₂O content and mortality was generally not significant.     

Comparison of absorbable and nonabsorbable sutures for intradermal skin closure in cats

Paired skin incisions were made in 6 cats and closed intradermally with the copolymer of glycolide, ɛ-caprolacton, and trimethylene-carbonate, or polypropylene suture. The macroscopic and histologic appearance of the incisions was compared. Polypropylene suture compared favorably to glycolide, ɛ-caprolacton, and trimethylene-carbonate suture for closure of skin incisions in cats.     

Mussel farming impacts on trophic status and benthic community structure in Maliakos Gulf (Eastern Mediterranean)

The impact of shellfish farming on the water column nutrient concentration and the benthic community structure was investigated seasonally at a mussel farm (Mytilus galloprovincialis L.) of Maliakos Gulf (Eastern Mediterranean). In most cases concentration of nutrients and chl a at the farm site was lower than those observed at the control sites. Statistical analysis in concentration of all nutrients and chl a indicated significant interactions between sites and seasons, which in all cases were temporal. Furthermore, no significant interactions were found between sites and seasons for all sediment and benthic community parameters, except for Shannon–Wiener diversity index and species richness. The significant interactions detected in the biotic data were temporal. Analysis of similarity and similarity percentages analysis revealed a certain fluctuation of benthic macrofaunal community during the overall sampling year mainly due to temporal rather than spatial effects. Cluster analysis and multidimensional scaling ordination plot indicated the clearly separation of the farm site and the control sites in most of the seasons. K-dominance curves showed small difference in elevation and overlap indicating minimal difference in biological stress between the farm site and the control sites. All the above indicates that probably the farming of mussels was beneficial for the trophic status of Maliakos Gulf and that there was a minimal environmental stress caused by the shellfish farming for the surrounding benthic environment.     

Determinants of farmers’ decisions on pesticide use in oriental tobacco: a survey of common practices

Information about pesticide use and perceptions of their risks among farmers is important for identifying problems associated with pest-control decisions and developing appropriate management practices in given crops. In tobacco, a plant sensitive to many pests and diseases, such information is lacking. The patterns of pesticide use in oriental tobacco, as well as the most important factors for farmers’ decisions relating to chemical pest control were studied among randomly selected farmers in northern Greece on the basis of self-reported information acquired through a pre-tested questionnaire. High reliance of farmers on pesticides and field use of all well-known classes of chemical pesticides were reported. While all the active ingredients reported were registered for pest control in tobacco, they differed considerably in terms of toxicity. A normal cropping season received at least 14–16 pesticide applications for soil disinfection, pest control, and weed control. Most farmers stated that they usually spray chemicals on a calendar basis or on the first appearance of a pest. Efficacy on target pests and market price of the pesticide products to be used were the most important criteria for selection of pesticides, i.e. products that are considered to be highly effective and/or that are cheap are more likely to be selected. Better-educated and more experienced farmers were found to pay more attention to environmental safety and pesticide toxicity. Most farmers felt that pesticide use can reduce crop damage by more than 75%, assuring high yields. Main determinants of pesticide use were primarily the fear of severe yield and economic losses and the doubts about the effectiveness and the correct implementation of alternative pest-control methods. Pesticide use could be reduced by exposing farmers to improved pest-control practices such as site-specific integrated pest management.     

Simulated Summertime Regional Ground-Level Ozone Concentrations over Greece

Ground-level ozone concentrations were estimated for Greece during a summer period of the year 2000 using the regional air quality model UAM-V off-line coupled with the mesoscale meteorological model MM5. An anthropogenic NOx, NMVOCs and CO emission inventory and biogenic NMVOCs emission data were used to support model simulations. The evaluation analysis indicates a quite satisfactory model performance in reproducing ozone levels. The simulated mean ozone concentrations are above the 32-ppb EU phytotoxicity limit over almost all continental and maritime areas of Greece. Over the greater part of the country, the background mean ozone levels range from 40 to 55 ppb. Ozone values higher than the 55-ppb EU human health protection limit reaching 60 ppb dominate part of the southern Aegean Sea that is influenced by the Athens urban plume. In the areas where anthropogenic emission densities are high, the mean ozone levels vary between 20 and 40 ppb. Over the greater part of Greece, the simulated mean daily maximum ozone concentrations range from 50 to 65 ppb. More enhanced maximum ozone concentrations up to 95 ppb mainly dominate over the greater areas of the two largest Greek urban centres (Athens and Thessaloniki) and over the continental and maritime areas south of Athens which are under the influence of the urban plume.     

The effect of genetic variation and nitrogen fertilization on productive characters of Greek oregano

This study aims to investigate the response of 10 Greek Oregano (Origanum vulgare subsp. hirtum) populations, collected across Greece, under 3 levels of N-fertilization during 2012 and 2013. The populations were differentiated for dry matter (from 32.7 to 63.3?g·pot^?1), for essential oil content (from 2.31 to 5.86?ml·100^?1?g dry weight) and for amount of essential oil (from 1.37 to 2.46?ml·pot^?1), for both years. Those with the highest dry matter (1-“Palaiochori” and 5-“Gliki”) and the highest essential oil content (10-“Gytheio” and 9-“Achladocastro”) were superior by 30%, as compared to the general mean of the experiment. The populations 3-“Litochoro” and 5-“Gliki” had an increased amount of essential oil (24%) as compared to the general mean of the experiment. An additional nitrogen supply (N₀ to N₁ level) increased dry matter production and amount of essential oil per pot, while decreased essential oil content for all populations. Further increase of nitrogen supply, favored six populations for dry matter production and two populations for amount of essential oil per pot while had almost no effect on five populations for essential oil content. The superior populations could be used in a breeding program as starting material for the development of new cultivars.     

Asymmetry of mating behaviour affects copulation success in two stored-product beetles

Lateralization (i.e. left–right asymmetries in the brain and behaviour) has been documented in all vertebrate classes, while evidences for invertebrates are limited. To the best of our knowledge, there is no information about behavioural asymmetries in the order Coleoptera. In this research, we investigated the lateralization of mating traits in two major pests of stored products: the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae), and the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae). Both T. confusum and S. oryzae males showed population-level left-biased copulation approaches of potential mates. Interestingly, T. confusum and S. oryzae males performing left-biased copulation attempts achieved higher mating success over right-biased males. Furthermore, S. oryzae males periodically exhibited a typical head wagging behaviour, which consists of waving the rostrum laterally across the female thorax and then resting the rostrum on the mid thorax. This behaviour was right-biased, even in the majority of males that previously showed left-biased copulation attempts. The quantification of mating displays could allow comparisons with other strains, in order to evaluate the impact of a given host or of the rearing methods on the mating traits of S. oryzae and T. confusum. Overall, this is the first report of lateralization of mating traits in Coleoptera. Furthermore, this research adds basic knowledge to the reproductive behaviour of S. oryzae and T. confusum.     

Chlorophyll meter readings,N leaf concentration and their relationship with N use efficiency in oregano

Plant-based diagnostic techniques such as chlorophyll meter (CM) readings and nitrogen (N) leaf concentration are used to determine the level of crop N nutrition, but research is limited on perennial crops and especially on aromatic and medicinal plants such as Greek oregano (Origanum vulgare spp. hirtum). The objectives of this study were to determine in a perennial crop species whether there is a relationship between the CM readings, N leaf concentration, and N use efficiency (NUE) and to use CM readings as a diagnostic tool for predicting dry matter yield in response to N fertilization. The CM readings varied across environments, growth stages, and fertilization treatments and were correlated with NUE. NUE was also affected by the environment, N fertilization, and interactions among these variables. This study provides new information about the effect of N application on CM readings, N leaf concentration, and NUE in a perennial crop such as oregano.     

Response of two pomegranate (Punica granatum L.) cultivars to six boron concentrations: Growth performance,nutrient status,gas exchange parameters,chlorophyll fluorescence,and proline and carbohydrate content

One-year-old, own-rooted pomegranate cultivars “Ermioni” and “Wonderful” plants were irrigated for 75 days with modified Hoagland nutrient solutions containing 0–10 mg L^?1 boron (B). At the end of the experiment, the control plants of “Ermioni” presented better growth performance than those of “Wonderful.” However, there were no differences in the treatments with high B concentration (5.0 or 10 mg L^?1). Control “Wonderful” plants had higher fresh and dry matter than control “Ermioni” plants. Moreover, the highest B concentrations in nutrient solution led to a significant increase in chlorophyll and carbohydrate content in the leaves of cultivar “Ermioni.” Furthermore, leaf proline concentration, gas exchange, chlorophyll fluorescence, and micro–macronutrients of both cultivars were not affected by any of the tested B treatments. B concentration in plant parts was linearly correlated to B supply. The highest B concentrations were observed in roots followed by stems and apical and basal leaves.     

Elemental Relationships and Growth and Development of Spinach Grown with Sewage Sludge

A pot experiment with spinach (Spinacia oleraceae L. Fam.: Chenopodiaceae) was conducted aiming to investigate the effect of the addition of sewage sludge (SS) on soil substrate, the growth of spinach, and the plant interactions of CaxCd and ZnxCd. There were six substrates obtained by mixing soil and sludge in different proportions by volume (20:1, 10:1, 6.7:1, 5.0:1, 4.0:1, 3.3:1) and a control (only soil). The highest biomass was achieved in treatments 20:1 and 10:1. There was not a linear increase due to toxicity when SS was added in higher proportions. Sludge improved soil fertility by increasing organic matter and total N. Furthermore, in all plant parts of spinach, the Ca and Zn contents were synergistically interrelated with the Cd content, facilitating Cd uptake. The use of sewage sludge as soil amendment is not applicable on agricultural land due to the accumulation of Cd in plant.