A Mathematical Model of Flavescence Dor\'ee Epidemiology

Flavescence dor\'ee (FD) is a disease of grapevine transmitted by an insect vector, $Scaphoideus$ $titanus$ Ball. At present, no prophylaxis exists, so mandatory control procedures (e.g. removal of infected plants, and insecticidal sprays to avoid transmission) are in place in Italy and other European countries. We propose a model of the epidemiology of FD by taking into account the different aspects involved into the transmission process (acquisition of the disease, latency and expression of symptoms, recovery rate, removal and replacement of infected plants, insecticidal treatments, and the effect of hotbeds). The model was constructed as a system of first order nonlinear ODEs in four compartment variables. We perform a bifurcation analysis of the equilibria of the model using the severity of the hotbeds as the control parameter. Depending on the non-dimensional grapevine density of the vineyard we find either a single family of equilibria in which the health of the vineyard gradually deteriorates for progressively more severe hotbeds, or multiple equilibria that give rise to sudden transitions from a nearly healthy vineyard to a severely deteriorated one when the severity of the hotbeds crosses a critical value. These results suggest some lines of intervention for limiting the spread of the disease

Seasonal and Daily Movement of Scaphoideus titanus Ball (Homoptera: Cicadellidae)

Seasonal and daily flight patterns of Scaphoideus titanus Ball were investigated in northern Italy, throughout a 3-yr period, using yellow sticky traps placed in an experimental vineyard. Capture data were also analyzed in relation to temperature and relative humidity values. The leafhopper was found to be more active from 1800 to 0800 hours, whereas little movement occurred during high light intensity hours. Although the sex ratio was always male biased, no difference in flight periodicity was found between genders. The seasonal flight peak occurred each year in different periods, ranging from the end of June to the beginning of July, depending on mean temperature values. Daily capture increases were correlated with daily minimum and maximum temperatures and were negatively correlated with maximum values of relative humidity. As a result, this species could be crepuscular or nocturnal, and a bimodal flight periodicity is likely

Models for the active optics system of the ASTRI SST-2M prototype proposed for the Cherenkov Telescope Array

ASTRI SST-2M is an end-to-end prototype of Small Size class of Telescope proposed for the Cherenkov Telescope Array (CTA). Currently under completion at the Serra La Nave observing station (Mt. Etna, Catania, Italy), the ASTRI SST- 2M telescope is the first imaging dual-mirror telescope ever realized for Cherenkov telescopes. A mini-array of nine such telescopes will form the ASTRI mini-array proposed as a precursor and initial seed of CTA to be installed at the final CTA southern site. ASTRI SST-2M is equipped with an active optics system, controlling both the segmented primary mirror and the monolithic secondary mirror, which allows optical re-alignment during telescope slew. We describe the hardware and software solution that have been implemented for optics control and the models we developed for the system