Comparison of chemical treatments for reducing epiphytic Pseudomonas savastanoi pv. savastanoi populations and for improving subsequent control of olive knot disease

The economic impact of the olive knot disease caused by Pseudomonas savastanoi pv. savastanoi (Psv) has dramatically increased in recent years, especially in high-density plantations. Here we report chemical control trials, performed in an olive grove planted with two susceptible cultivars, Arbequina and Picudo, over a four-year period. The effect of treatments made with copper oxychloride, cuprocalcic sulfate plus mancozeb or acibenzolar-S-methyl on the Psv populations and subsequent appearance of the disease were evaluated. Both copper treatments reduced the proportion of samples where Psv was isolated, and greatly reduced Psv populations in trees of cv. Picudo. The effect of copper on Psv populations was observed after the first application, but the greatest differences between copper-treated and untreated plants were observed in the third year, after five copper applications. No resistance to copper was detected in the remaining epiphytic Psv populations in treated plants. The average number of knots per plant was significantly lower in copper-treated plants than in untreated plants. By contrast, acibenzolar-S-methyl did not reduce either Psv populations or the disease during the study. These results support the usefulness of copper treatments for olive knot management. Results indicate that two copper treatments should be performed regularly under an integrated control program, especially in high-density groves, since their efficiency was demonstrated not only in decreasing olive knot incidence, but also in reducing Psv populations.     

Assessment of the Microbiological Safety of Dried Spices and Herbs Commercialized in Spain

Spices and herbs are natural products or their blends that must be free of extraneous matter content. Conventional production of these products implicates a number of hygienic problems so spices and herbs may be exposed to a wide range of microbial contamination during pre- and post-harvest and they can present high microbial counts. In this study, we have analyzed the microbial quality of 53 samples of spices and dry herbs collected from Spanish markets detecting a contamination of samples of spices with mesophilic aerobic counts (10%) and Enterobacteriaceae (20%). The analysis from herbs showed that the percentage of contamination was 26% in both microbiological values. Pathogenic microorganisms like Staphylococcus aureus, Yersinia intermedia, Shigella spp., Enterobacter spp., Acinetobacter calcoaceticus and Hafni alvei were also isolated from spices and herbs. These unsatisfactory results showed a poor microbiological quality. Spices and dry herbs are used as ingredients in a variety of products prepared in different ways, this fact suggests the need to provide a control system to improve the quality of herbs and spices.     

Feedbacks between fuel reduction and landscape homogenisation determine fire regimes in three Mediterranean areas

In densely populated areas like the Mediterranean, wildfire extent is mostly limited by fire suppression and fuel fragmentation. Fire is known to spread more easily through high fuel loads and homogenous terrain and it is supposed to reduce fuel amount and continuity, creating a negative feedback. Here we combine information from administration fire records, satellite imagery fire scars and land use/cover maps to asses the effects of fire on landscape structure and vice versa for three areas in Catalonia (NE Spain). We worked with three spatial focuses: the actual fire scar, 1 km² squares and 10 km² squares. In these regions agriculture land abandonment has lead to increased fuel continuity, paralleled by an increment of fire size. We confirm that fire spread is facilitated by land use/cover types with high fuel load and by homogeneous terrain and that fire reduces fuel load by transforming forests into shrublands. But we also found that fire increased landscape homogeneity, creating a positive feedback on fire propagation. We argue that this is possible in landscapes with finer grain than fire alone would create. The lack of discontinuities in the fuel bed diminishes the extinction capacity of fire brigades and increases the risk of large fires. We recommend that fire management should focus more on conservation of the traditional rural mosaic in order to prevent further increases in fuel continuity and fire risk.     

The effects of forest structure on the risk of wind damage at a landscape level in a boreal forest ecosystem

? The aim of this work was to analyze how the forest structure affects the risk of wind damage at the landscape level in a boreal forest.

? This was done by employing: (i) Monte Carlo simulation technique for generating landscapes with different age class distributions, proportions of open areas (gaps), and tree species composition; and (ii) a mechanistic wind damage model, HWIND, for predicting the critical wind speeds at downwind stand edges of open areas (gaps) for risk consideration. The level of risk of wind damage observed at the landscape level was significantly affected by the presence of gaps and old stands. Even a slight increase in the proportion of gap areas or older stands had a significant impact on the total length of edges at risk. As a comparison, variation in species composition (Scots pine and/or Norway spruce) had much smaller impact on the risk of damage.

? In conclusion, the effects of forest structure on the risk of wind damage should especially be considered by forest managers in day-to-day forest planning in order to reduce the risk of wind damage both at the stand and landscape level.

     

Guidance Level for Brevetoxins in French Shellfish

Brevetoxins (BTXs) are marine biotoxins responsible for neurotoxic shellfish poisoning (NSP) after ingestion of contaminated shellfish. NSP is characterized by neurological, gastrointestinal and/or cardiovascular symptoms. The main known producer of BTXs is the dinoflagellate Karenia brevis, but other microalgae are also suspected to synthesize BTX-like compounds. BTXs are currently not regulated in France and in Europe. In November 2018, they have been detected for the first time in France in mussels from a lagoon in the Corsica Island (Mediterranean Sea), as part of the network for monitoring the emergence of marine biotoxins in shellfish. To prevent health risks associated with the consumption of shellfish contaminated with BTXs in France, a working group was set up by the French Agency for Food, Environmental and Occupational Health & Safety (Anses). One of the aims of this working group was to propose a guidance level for the presence of BTXs in shellfish. Toxicological data were too limited to derive an acute oral reference dose (ARfD). Based on human case reports, we identified two lowest-observed-adverse-effect levels (LOAELs). A guidance level of 180 µg BTX-3 eq./kg shellfish meat is proposed, considering a protective default portion size of 400 g shellfish meat.     

Determinants of drought effects on crown condition and their relationship with depletion of carbon reserves in a Mediterranean holm oak forest

Severe droughts may increase physiological stress on long-lived woody vegetation, occasionally leading to rapid defoliation and progressive increase in mortality of overstorey trees. Over the last few years, episodes of drought-induced tree dieback have been documented in a variety of woodlands and forests around the world. However, the factors determining tree survival and subsequent recovery are still poorly understood, especially in resprouter species. We have studied the effects of a single drought episode on crown condition in a holm oak (Quercus ilex L.) forest located in NE Spain 7 years after the drought event. Generalized linear models were used to study the environmental correlates of forest crown condition 7 years after the drought event. Additionally, we evaluated the association between crown condition and the carbon and nutrient reserves stored in lignotubers 7 years after the drought. Our study reveals the multifactor nature of a drought-driven forest dieback in which soil depth and the characteristics of individual trees, particularly their number of stems, determined a complex spatial pattern of tree-level responses. This dieback was associated with a depletion of the carbon reserves in lignotubers 7 years after the episode, representing a reduction of up to 60% in highly drought-damaged trees. Interestingly, in the absence of new acute droughts, successive surveys in 2007-11 showed a direct association between carbon reserves depletion and further deterioration of crown condition. More frequent droughts, as predicted by climate change projections, may lead to a progressive depletion of carbon reserves and to a loss of resilience in Mediterranean resprouter species.     

Stomatal patchiness in the Mediterranean holm oak (Quercus ilex L.) under water stress in the nursery and in the forest

The evergreen holm oak Quercus ilex L. is the most representative tree in Mediterranean forests. Accurate estimation of the limiting factors of photosynthesis for Q. ilex and the prediction of ecosystem water-use efficiency by mechanistic models can be achieved only by establishing whether this species shows heterogenic stomatal aperture, and, if so, the circumstances in which this occurs. Here, we collected gas-exchange and chlorophyll fluorescence data in Q. ilex leaves from a nursery to measure the effects of stomatal oscillations on PSII quantum yield (Φ(PSII)) under water stress. Stomatal conductance (g(s)) was used as an integrative indicator of the degree of water stress. Images of chlorophyll fluorescence showed heterogeneous Φ(PSII) when g(s) was <50 mmol H(2)O m(-2) s(-1), representative of severe drought and corresponding to a container capacity <45%. Stomatal patchiness was related to a coefficient of variation (CV) of Φ(PSII) values >2.5%. A parallel study in the forest confirmed heterogeneous Φ(PSII) values in leaves in response to declining water availability. Three kinds of Q. ilex individuals were distinguished: those resprouting after a clear-cut (resprouts, R); intact individuals growing in the same clear-cut area as resprouts (controls, C); and intact individuals in a nearby, undisturbed area (forest controls, CF). Patchiness increased in C and CF in response to increasing drought from early May to late July, whereas in R, Φ(PSII) values were maintained as a result of their improved water relations since the pre-existing roots were associated with a smaller aerial biomass. Patchiness was related to a % CV of Φ(PSII) values >4 and associated in the summer with mean g(s) values of 30 mmol H(2)O m(-2) s(-1). Under milder drought in spring, Φ(PSII) patchiness was less strictly related to g(s) variations, pointing to biochemical limitants of photosynthesis. The occurrence of heterogenic photosynthesis caused by patchy stomatal closure in Q. ilex during severe drought should be taken into account in ecosystem modelling in which harsher water stress conditions associated with climate change are predicted.     

Swine influenza virus infection dynamics in two pig farms; results of a longitudinal assessment

ABSTRACT: In order to assess the dynamics of influenza virus infection in pigs, serological and virological follow-ups were conducted in two whole batches of pigs from two different farms (F1 and F2), from 3 weeks of age until market age. Anti-swine influenza virus (SIV) antibodies (measured by ELISA and hemagglutination inhibition) and nasal virus shedding (measured by RRT-PCR and isolation in embryonated chicken eggs and MDCK cells) were carried out periodically. SIV isolates were subtyped and hemagglutinin and neuraminidase genes were partially sequenced and analyzed phylogenetically. In F1, four waves of viral circulation were detected, and globally, 62/121 pigs (51.2%) were positive by RRT-PCR at least once. All F1 isolates corresponded to H1N1 subtype although hemagglutination inhibition results also revealed the presence of antibodies against H3N2. The first viral wave took place in the presence of colostral-derived antibodies. Nine pigs were positive in two non-consecutive sampling weeks, with two of the animals being positive with the same isolate. Phylogenetic analyses showed that different H1N1 variants circulated in that farm. In F2, only one isolate, H1N2, was detected and all infections were concentrated in a very short period of time, as assumed for a classic influenza outbreak. These findings led us to propose that influenza virus infection in pigs might present different patterns, from an epidemic outbreak to an endemic form with different waves of infections with a lower incidence.     

Mummified Fetus in the Thoracic Cavity of a Domestic Short-haired Cat

This short communication describes the diagnosis, treatment, and clinical course of a domestic short-haired cat with diaphragmatic hernia in which the herniated structure in the thoracic cavity contained a mummified fetus. The cat was pregnant when rescued from the street and, days later, gave birth without abnormalities. Some months later, during an ovariohysterectomy, an abnormal localization of the uterus was observed, and at that time the case was referred to our center. A thoracic radiograph showed an abnormal thoracic mass cranial to the heart. The main suspicion was the presence of a thoracic hernia with the uterus herniated and containing a mummified fetus. A thoracotomy was performed to confirm the nature of the mass and reduce the diaphragmatic hernia. Although this clinical case is quite rare, a mummified fetus can be observed in thoracic hernias.