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In the current global context, with an increasing number of undernourished people and worldwide food demand for the steady population growth[1], the correct and reasonable use of all the available plant protection measures is expected to play a key role in limiting agricultural yield losses caused by various plant diseases, during both the pre- and postharvest production stages. Fungal diseases represent one of the main problems affecting the quality as well as quantity of agricultural production and food industry. Crop protection is usually achieved by the widespread use of synthetic fungicides. It is now recognized that an extensive use of such fungicides is associated with a range of environmental risks[2]. Innovative technologies, based on sustainability, human safety, and long-term eco-safety, are increasingly required. The atmospheric pressure low temperature plasma is becoming a suitable alternative/complementary tool[3]. In this contribution, we report on the effect of plasma treatment on important hytopathogenic fungi. Selected fungi cause quantitative and qualitative losses of agricultural production both in the field and postharvest. In detail, we focus our attention on the in vitro direct inhibitory effect of non-contact SDBD on spore germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. Relatively short treatment time (few minutes) were required to completely inactivate the fungi on the growth medium. Morphological analysis of spores made by Scanning Electron Microscopy imaging suggests that the main mechanism is etching that could be attributed either to Reactive Oxygen Species or UV radiation, even though with a minor contribution, produced by plasma. Spectroscopic analysis of plasma generated in humid air provides an important evidence that the gas temperature of the active plasma layer should not play decisive role being very close to room temperature. In vivo experiments were also carried out on cherry fruits. The results demonstrate that inactivation of spores by direct inhibitory effect of surface DBD plasma is giving the fresh produce a shelf life longer that the artificially inoculated untreated one. Moreover, pre-treatment of fruit before inoculation improves the resistance to pathogen maybe activating the self-defense of the plant tissues.

The quarantine bacterium Xylella fastidiosa occurred for the first time in the open field in Europe in 2013, in southern Apulia (Italy), posing a serious threat to the agriculture economy and the biodiversity of the whole area. Infections caused by the subspecies pauca strain "De Donno" of this bacterium turned to be extremely aggressive on olive, causing leaf scorching and desiccation symptoms, a disease named Olive Quick Decline Syndrome. Research efforts were devoted to gain basic knowledge of the genetic and epidemiology of the olive strain (e.g. host pathogenicity and range, insect vector(s), and fundamental drivers of its epidemics), in order to find strategies to control its spread or mitigate symptoms [1]. In this contest we explored the feasibility of using low temperature plasma to kill bacterial cells. Low temperature plasma is an environment rich of reactive oxygen and nitrogen species (ROS and RNS) efficient in the decontamination, sterilization, and chemical modification of surfaces. Moreover it presents numerous potential advantages over conventional methods, such as its nontoxic nature, low process operational costs, short treatment time at low temperatures.[2] Preliminary experiments were conducted in vitro to test the biocidal effect of plasma roduced by a surface dielectric barrier discharge on the bacteria. The results were quite encouraging showing that plasma reached high decontamination rate also on biofilm protected colonies of Xylella growing on solid media. Plasma application to trees will require developing protocols and tools able to reach the bacterium, which localizes and replicates in the xylem vessels. Thus, we explored the possibility to administer the plasma cure via water. The rationale was to use the plasma to activate water [3] as a biocidal agent that could freely move inside the xylem system. Preliminary results in liquid culture medium show a complete inactivation of Xylella cells, paving the way to test on model plants in confined conditions.

The need of environment-friendly strategies for food production and plant protection makes the use of plasma-assisted technologies in agriculture as an innovative practice [1]. The non-equilibrium character of low temperature plasmas enables the production of reactive oxygen and nitrogen species (ROS and RNS) efficient in the decontamination, sterilization and chemical modification of surfaces. On seeds, the plasma treatment affects the basic physiological processes improving germinability and biometric parameters of plantlets [2]. We focused on the effect of plasma treatment on the morphology of seeds, germination and radicle development, either by using imaging techniques such as high-resolution computed X-ray microtomography (µXCT) or by following the development of seeds germination in vitro and in an artificial soil-like substrate. Since seeds germination relies mainly on the accumulation of mineral macronutrients (such as N, K, Ca, Mg, P, and S) and micronutrients (such as Cl, Fe, B, Mn, Zn, Cu, Mo, and Ni, generally in the range of ppm) in certain seed tissues [3], X-ray micro-fluorescence (m-XRF) was used to investigate the localization of mineral elements in seeds before and after plasma treatment [4]. Our results show that plasma treatment changed neither seed structure nor morphology. The increase of the germination rate was observed together with better developed root apparatus and improved biometric parameters. Moreover, we observed that macro- and micro-nutrients concentrated in the radicle, moving from the endosperm and the cotyledons. Redistribution of these elements could explain the faster germination of the plasma-treated seeds, being a similar process as generally observed in seed tissues during germination. The plasma treatment is therefore somehow anticipating and implementing the mobilization of key-nutrients towards the radicle, resulting in faster and higher germination of the seeds as well as improved characteristics of the plantlet, especially at the root level.

The ESCAMPIG XVIII is approved as an Europhysics Conference by the European Physical Society and supported both by its Atomic and Molecular Physics Division and Plasma Physics Division. The European Sectional Conference on the Atomic and Molecular Physics of Ionized Gases (ESCAMPIG) is biennial event (EPS, Europhysics Conference) focussing on collisional and radiative aspects of atomic and molecular physics in partially ionized gases as well as on plasma surface interaction The 18th confrence (ESCAMPIG XVIII) is organized in Lecce (Italy) from th 12th to th 16th July 2006 by the Institute of Inorganic Methodologies and Plasmas (Bari, Rome, Potenza) of the Italian National Research Council (CNR-IMIP) and the Chemistry Depertment of the UNiversity of Bari. The conference covers the following topics: 1. Atomic and molecular processes in plasmas 2. Particle energy distribution functions3. Discharge physics: Sheats, transport processes, adn modelling 4. Plasma Diagnsotics 5. Laser and particle beam assisted plasma processes 6. Physical basis of plasma chemistry and plasma surface interactions

Hydrogenated microcrystalline silicon (mc-Si:H) films have been prepared by Plasma Enhanced Chemical Vapour Deposition (PECVD) from a mixture of silane highly diluted in hydrogen. The effect of the molecule dwell time on the deposition rate and on the electrical and structural properties has been investigated. The molecule dwell time appears to control orientation and grain size. Highly conductive mc-Si:H films with rough surface have been grown with high deposition rate at higher molecule dwell time in an appropriate silane concentration. These films show an enhancement of the optical absorption in the near infrared region suitable for PV applications