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Papers by Antonello Cossu

RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, Sep 1, 2010

Journal of Plant Pathology, 2009

A dynamic model for Plasmopara viticola primary infections was evaluated by comparing model predi... more A dynamic model for Plasmopara viticola primary infections was evaluated by comparing model predictions with disease onset in: (i) 100 vineyards of northern, southern and insular Italy (1995 to 2007); (ii) 42 groups of potted grapevine plants exposed to inoculum (2006 to 2008). The model simulates the development of any oospore cohort during the primary inoculum season, including oospore germination, production and survival of sporangia, release, survival and dispersal of zoospores, and infection and incubation. The model showed high sensitivity, specificity, and accuracy both in vineyards and in potted plants. The true positive and negative proportions were TPP=0.99 and TNP=0.87, respectively. Because of a certain proportion of false positive predictions (FPP=0.13), confidence in prediction of non-infections was higher than in prediction of infections. These wrong predictions occurred early in the season or when oospore inoculum was low, or were triggered by isolated weak rain even...

EPPO Bulletin, 2007

Plasmopara viticola , the causal agent of grapevine downy mildew, requires fungicide treatments t... more Plasmopara viticola , the causal agent of grapevine downy mildew, requires fungicide treatments to avoid severe yield losses, so epidemiological models have been elaborated to better manage fungicide scheduling. Primary oosporic inoculum plays a key role in epidemic development, and some of these models have been elaborated following an empirical approach to define quantitative relationships between occurrences of primary infections and weather factors influencing them. Recently, a mechanistic dynamic model was elaborated which accounts for the biological effects of weather on the different stages of the primary infection chain, from the progressive breaking of dormancy in the overwintering oospore population to infection establishment. In this work, three widely used models (3-10 rule, EPI and DMCast) were compared with this model (named UCSC model) on the basis of their theoretical approaches and their accuracy was tested against real data collected over a 9-year period in Sardinia (Italy). The two empirical models, 3-10 and EPI, seem to be too oversimplified to simulate correctly a complex biological phenomenon such as the sexual stage of P. viticola they lack consideration of some key stages of the infection chain and simultaneously simulate various biological events, each of which are influenced by specific weather conditions. EPI, in particular, needs specific calibrations and ongoing processes of adaptation that make its use in disease warning difficult. DMCast overcomes these problems because of its mechanistic approach; nevertheless, the empirical method used to model oospore maturation requires validations and, as in the present case, modifications before practical use. The UCSC model, due to its fully mechanistic approach, does not present this problem and provides accurate dynamic simulations of the sexual stage of P. viticola , with a high degree of detail and requiring neither calibrations nor corrections.

The need for agroecosystem analysis has increased due to additional complexity brought about by c... more The need for agroecosystem analysis has increased due to additional complexity brought about by climate change. In this paper, a multi-trophic system model is applied to the analysis of olive systems in Sardinia (Italy) using a 105-year climate scenario for the Alghero location. This scenario includes 50 years (1951-2000) of observed weather and 55 years (2001-2055) of weather projected according to the observed 1951-2000 trend. General physiologically based demographic models that apply to all species at all trophic levels, are used to simulate the effects on olive system dynamics of observed and projected weather included in the Alghero climate scenario.

Egu General Assembly Conference Abstracts, May 1, 2010

The availability of a long data series of fire perimeters combined with a detailed knowledge of t... more The availability of a long data series of fire perimeters combined with a detailed knowledge of topography and land cover allow to understand which are the main features involved in forest fire occurrences and their behaviour. In addition, climate indexes obtained from the analysis of time series with more than 20 years of complete records allow to understand the role

Fluviokarstic catchments are difficult to model especially during a flood event because of their ... more Fluviokarstic catchments are difficult to model especially during a flood event because of their hydrological com-plexity. The hydrological characterization is even more challenging for ungauged rivers. In the last five winters (2004-2008) several exceptional meteorological events ...

Geomorphology, May 7, 2010

The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gy... more The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gypsum speleothems are, in general, very low in U content, challenging the limits of detection methods. Various approaches to dissolving gypsum and isolation of actinides from the matrix include ion-pairing dissolution with magnesium salts and using nitric acid. The most precise dating technique is Thermal Ionization Mass Spectrometry (TIMS), combined with Fe(OH) 3 scavenging and anionic exchange chromatography. Less satisfactory, but much quicker, is direct retention of actinides from HNO 3 by means of TRU resin and MC-ICP-MS detection. We have tested these methods on gypsum speleothems from the Sorbas karst in Spain and from the Naica caves in Mexico.

Il presente lavoro è stato pubblicato su L'Informatore Agrario n°21 del 2004.

Summary We present an analysis of precipitation in an area of Sardinia (Italy) at high hydrogeolo... more Summary We present an analysis of precipitation in an area of Sardinia (Italy) at high hydrogeological risk. Sardinia is an island located in the Western Mediterranean Sea. Precipitation is here a highly irregular phenomenon due to the variability of extra-tropical cyclones. The latitudinal development of the island (~200 Km) gives a climatic North-South gradient. However, the presence of high and

Phytopathologies affecting viticulture, such as grapevine downy mildew (Plasmopara viticola), are... more Phytopathologies affecting viticulture, such as grapevine downy mildew (Plasmopara viticola), are depending on meteorological trend. Diseases are controlled with the use of fungicides, which has considerable economic costs, negative effects on environment, human health and wine quality. This strategy should be reconsidered through introducing methods to reduce the use of chemicals. In order to act promptly, it is necessary to know the correct incubation period and an accurate knowledge of meteorological parameters such as temperature, humidity and precipitation is required. This project is an example of metrological approach applied to agrometeorological studies. The aims are: improvement of the meteorological observations in field by applying a metrological approach and calibration methods; evaluation of the uncertainties; implementation of traceability in meteorological measurements; and improvement of the forecasting models by inclusion of measurement uncertainties in the input v...

Italian Journal of Agrometeorology

Phytopathologies such as grapevine downy mildew (Plasmopara viticola), one of the most important ... more Phytopathologies such as grapevine downy mildew (Plasmopara viticola), one of the most important disease affecting viticulture, are depending on weather conditions and meteorological trend. The disease is currently controlled through the massive use of fungicides, which has considerable economic costs, negative effects on environment, human health and wine quality. This strategy should be reconsidered through introducing methods to substantially reduce the use of chemicals. In order to act promptly, it is necessary to know the correct incubation period and an accurate knowledge of meteorological parameters such as temperature, humidity and precipitation is required. This project is the first example at European level of metrological approach applied to agricultural meteorological studies. The aims are: (i) improvement of the meteorological observations in field by applying a metrological approach and calibration methods for automatic weather stations in homogeneous agricultural site...