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Grapevine yellows (GY) of grapes, a critical threat to grapevines because of the severe symptoms and the lack of healing treatments, has been detected worldwide. The detection of GY diseases is a very difficult and time consuming task, and relies on symptoms identification, which are very similar with other diseases. Additionally, the analysis of asymptomatic GY-infected grapes could lead to high rates of false-negative due of the low concentration of the pathogen in the host. Herein, we present a supporting vision-based tool for GY disease detection using artificial intelligence (AI) and machine learning (ML). Leaves of bois noir-infected plants (previously tested by qPCR) were collected in July-October, 2017. Grapevine yellow was detected in a data set of 322 images and six diseases. Other than grapevine yellow, the diseases include downy mildew, esca disease, grapevine leafroll, powdery mildew and Stictocephala bisonia. A linear support vector machine (SVM) classified features from a pre-trained convolutional neural network - AlexNet trained on ImageNet. The system obtains a 95.23% accuracy and a Matthew's correlation coefficient of 0.832. For reference, a baseline system with local binary patterns (LBP) and color histogram with a SVM obtains only 26.7% and -0.124, respectively. Our work shows promise for automatic detection of grapevine yellow by computers. Future work will focus on improving the sensitivity of the system and implementation on drones with Nvidia Jetson. This system could reduce the rate of false positive/negative in large-scale vineyard monitoring.

Grapevine “bois noir”, related to the presence of ‘Candidatus Phytoplasma solani’ (‘Ca. P. solani’), represents a serious threat in several vine-growing areas worldwide. In surveys conducted over two years, mild and/or moderate symptoms and lower pathogen titer were mainly associated with ‘Ca. P. solani’ strains harboring a secY gene sequence variant (secY52), whereas severe symptoms and higher titer were mainly observed in grapevines infected by phytoplasma strains carrying any one of another four variants. A comparison of amino acid sequences of the protein SecY of ‘Ca. P. solani’ strains revealed the presence of conservative and semi-conservative substitutions. The deduced three-dimensional (3D) protein analysis unveiled that one semi-conservative substitution identified in the sequence variant secY52 is responsible for a structural disordered region that probably confers a flexibility for binding to distinct molecular complexes. In fact, the other analyzed variants show an organized structure and the 3D in silico prediction allowed the identification of β-sheets. Thus, differences in symptom severity and pathogen concentration observed in grapevines infected by ‘Ca. P. solani’ strains carrying distinct secY gene sequence variants suggest a possible relationship between SecY protein structure and phytoplasma strain virulence.

Bois noir is a disease associated with the presence of phytoplasma &lsquo, Candidatus Phytoplasma solani&rsquo, belonging to the Stolbur group (subgroup 16SrXII-A), which has a heavy economic impact on grapevines. This study focused on the changes induced by phytoplasma in terms of the profile and amount of secondary metabolites synthesized in the phenylpropanoid pathway in leaves of Vitis vinifera L. red-berried cultivar Sangiovese. Metabolic alterations were assessed according to the disease progression through measurements of soluble sugars, chlorophyll, and phenolic compounds produced by plant hosts, in response to disease on symptomatic and asymptomatic Bois noir-positive plants. Significant differences were revealed in the amount of soluble sugars, chlorophyll, and accumulation/reduction of some compounds synthesized in the phenylpropanoid pathway of Bois noir-positive and negative grapevine leaves. Our results showed a marked increase in phenolic and flavonoid production and a parallel decrease in lignin content in Bois noir-positive compared to negative leaves. Interestingly, some parameters (chlorophyll a, soluble sugars, total phenolic or flavonoids content, proanthocyanidins, quercetin) differed between Bois noir-positive and negative leaves regardless of symptoms, indicating measurable biochemical changes in asymptomatic leaves. Our grapevine cultivar Sangiovese results highlighted an extensive modulation of the phenylpropanoid biosynthetic pathway as a defense mechanism activated by the host plant in response to Bois noir disease.

To evaluate the effects on modulation of K+ channel in antiviral treatments, we report the application of potassium channel blockers (PCBs) tetraethylammonium chloride (TEA) and cesium chloride (Cs) in in vitro plantlets or callus cultures infected by Tobacco mosaic virus (TMV). The effect of PCBs were evaluated in: a) in vitro TMV-infection trials, where PCB-treatments were applied during infection process of healthy plantlet; b) chemotherapy trials, where PCB-treatments were applied in combination to antiviral drugs on TMV-infected plantlets; c) in antiviral trials using callus culture and sieving technique. Both PCBs were able to reduce relative concentration of virus [calculated as Fold Changes (FC) relative to control samples] during infection process, with major effect observed at 7 dpi and in medium or upper portions of plantlet. Positive effects of PCBs were also observed following chemotherapy trials, where TEA significantly improves antiviral effectiveness of the antiviral drugs, causing higher FC compared to that obtained with just chemotherapy treatment since 3th subculture. Nevertheless, plantlets were positive to TMV up to 6th subculture, thus virus elimination was not achieved). Finally, the callus culture and sieving technique lead to 11.1 ± 3.8% of TMV-negative plantlets, while TEA-treated mother-calli lead to 22.2 ± 3.8% of negative plantlets. Concluding, findings suggest that modulation of K+, previously indicated as essential in early stages of viral infection, could be also involved in antiviral techniques.

Bois noir (BN), associated with &lsquo, Candidatus Phytoplasma solani&rsquo, (CaPsol), is the most widespread disease of the grapevine yellows complex worldwide. In this work, BN epidemiology was investigated in a case study vineyard where an unusual CaPsol strain, previously detected only in other host plants, was found to be prevalent in grapevine. Experimental activities included: symptom observation, sampling of symptomatic vines, Auchenorrhyncha specimens, and weeds, molecular detection and typing of CaPsol strains, statistical analyses for determining possible relationships between CaPsol relative concentration, strain type, and symptom severity. Among insects, Reptalus quinquecostatus was the most abundant and was found to be highly infected by CaPsol, while Hyalesthes obsoletus, the main CaPsol vector, was not caught. Moreover, R. quinquecostatus harbored CaPsol strains carrying uniquely the stamp sequence variant St10, also identified as prevalent in vines and in the majority of weeds, and all the secY variants identified in the vineyard. Statistical analyses revealed that CaPsol strains carrying the St10 variant are not associated with severe symptoms, suggesting their possible moderate virulence. Based on such evidence, a new BN epidemiological pattern related to these CaPsol strains and involving grapevine, R. quinquecostatus, and/or weeds is proposed. Furthermore, the possible presence of other players (vectors and weeds) involved in CaPsol transmission to grapevines was highlighted.

The establishment of permanent cover crops is becoming a common practice in vineyard floor management. Turfgrass science may provide species and techniques with a high potential for improving the sustainability of vineyard floor management. Based on this assumption, an experiment was carried out during 2018 and 2019 at the Donna Olimpia Vineyard, Bolgheri, Italy. The trial aimed at comparing an innovative floor management system based on a turf-type cultivar of bermudagrass mown with an autonomous mower with a conventional floor management system. Ground cover percentage, energy consumption, CO2 emissions, grapevine water status, leaf nitrogen content, fruit yield and must composition have been assessed in order to perform the comparison. The innovative vineyard floor management produced an almost complete ground cover (98%) at the end of the second growing season, with the resident species reduced to a small percentage (4%). Resident species growing under-trellis were efficiently controlled without herbicide applications. A lower primary energy consumption and a reduction in CO2 emissions were observed for the innovative management system compared to the conventional management system. Grapevine water status, leaf chlorophyll content, soil&ndash, plant analyses development (SPAD), fruit yields and must composition were similar between the different soil management systems. Based on results obtained in this trial, turf-type bermudagrass and innovative mowing machines may contribute to enhance the sustainability of vineyard floor management.

Grapevine Bois noir (BN) is associated with infection by &ldquo, Candidatus Phytoplasma solani&rdquo, (CaPsol). In this study, an array of CaPsol strains was identified from 142 symptomatic grapevines in vineyards of northern, central, and southern Italy and North Macedonia. Molecular typing of the CaPsol strains was carried out by analysis of genes encoding 16S rRNA and translation elongation factor EF-Tu, as well as eight other previously uncharacterized genomic fragments. Strains of tuf-type a and b were found to be differentially distributed in the examined geographic regions in correlation with the prevalence of nettle and bindweed. Two sequence variants were identified in each of the four genomic segments harboring hlyC, cbiQ-glyA, trxA-truB-rsuA, and rplS-tyrS-csdB, respectively. Fifteen CaPsol lineages were identified based on distinct combinations of sequence variations within these genetic loci. Each CaPsol lineage exhibited a unique collective restriction fragment length polymorphism (RFLP) pattern and differed from each other in geographic distribution, probably in relation to the diverse ecological complexity of vineyards and their surroundings. This RFLP-based typing method could be a useful tool for investigating the ecology of CaPsol and the epidemiology of its associated diseases. Phylogenetic analyses highlighted that the sequence variants of the gene hlyC, which encodes a hemolysin III-like protein, separated into two clusters consistent with the separation of two distinct lineages on the basis of tufB gene sequences. Alignments of deduced full protein sequences of elongation factor-Tu (tufB gene) and hemolysin III-like protein (hlyC gene) revealed the presence of critical amino acid substitutions distinguishing CaPsol strains of tuf-type a and b. Findings from the present study provide new insights into the genetic diversity and ecology of CaPsol populations in vineyards.

Lily mottle virus (LMoV), a member of the genus Potyvirus, is one of the main viruses infecting lily. Symptoms on lily differ according to the susceptibility and sensitivity of different cultivars and hybrids. They range from leaf mottle or mosaic, vein clearing, chlorotic and yellow streaking, leaf curling, and necrotic spots, to milder forms of leaf symptoms. Plants may even be symptomless at some stages of growth. A varietal collection of Lilium from the early 1990s is held in Pistoia Province (Tuscany, Italy) and is composed of Asian hybrids obtained from intraspecific breeding of commercial cultivars. During a survey conducted from May to June 2010, several plants showing vein clearing, leaf mottle, leaf mosaic, and reddish brownish necrotic spots were observed. Leaf samples from 60 symptomatic or symptomless lily plants, belonging to 20 cultivars, were collected and tested for the presence of LMoV. Samples were assayed by double-antibody sandwich (DAS)-ELISA and eight of them, belonging to four different cultivars, tested positive. Total RNA was extracted from 2 g of leaf tissue of every collected sample according to the protocol described earlier (3) and cDNA synthesis was performed with an iScript cDNA Synthesis Kit (Bio-Rad, Hercules, CA). Samples were tested by reverse transcription (RT)-PCR and real-time PCR assays using primers LMoV1 (5′-GCAAATGAGACACTCAATGCTG-3′) and LMoV2 (5′-CGTGCGTGAAGTAACTTCATAG-3′) designed to amplify 651 bp of the coat protein (CP) gene of LMoV (1). Results obtained with RT-PCR and real-time PCR exactly matched those achieved with ELISA assay, and the eight positive samples showed amplicons of the expected size. PCR products from five infected samples were directly sequenced from both directions and submitted in GenBank (Accessions Nos. JQ655106 to JQ655110). Our isolates share more than 99% nucleotide identity among each other. Comparison with other LMoV-CP gene sequences present in GenBank showed nucleotide identities ranging from 93 to 94% with LMoV isolates from South Korea (GenBank Accession Nos. GQ150683 to GQ150686), China (GenBank Accession Nos. EU348826, AJ748256, AJ564636, and AJ564637), Australia (GenBank Accession No. JN127341), and Japan (GenBank Accession No. AB570195). To our knowledge, this is the first report of LMoV on Lilium in Italy where this virus was already reported to infect escarole (2). Considering the economic importance of Lilium production as a flowering plant in Pistoia Province, and in several other areas of Italy, the report of LMoV present on lilies suggests the use of healthy propagation material and the adoption of preventive measures to avoid its diffusion. References: (1) J.-H. Lim et al. Korean J. Microbiol. 45:251, 2009. (2) V. Lisa et al. Plant Dis. 86:329, 2002. (3) D. J. MacKenzie et al. Plant Dis. 81:222, 1997.

Grapevine yellows (GY) are a significant threat to grapes due to the severe symptoms and lack of treatments. Conventional diagnosis of the phytoplasmas associated to GYs relies on symptom identification, due to sensitivity limits of diagnostic tools (e.g. real time PCR) in asymptomatic vines, where the low concentration of the pathogen or its erratic distribution can lead to a high rate of false-negatives. GY’s primary symptoms are leaf discoloration and irregular wood ripening, which can be easily confused for symptoms of other diseases making recognition a difficult task. Herein, we present a novel system, utilizing convolutional neural networks, for end-to-end detection of GY in red grape vine (cv. Sangiovese), using color images of leaf clippings. The diagnostic test detailed in this work does not require the user to be an expert at identifying GY. Data augmentation strategies make the system robust to alignment errors during data capture. When applied to the task of recognizing GY from digital images of leaf clippings—amongst many other diseases and a healthy control—the system has a sensitivity of 98.96% and a specificity of 99.40%. Deep learning has 35.97% and 9.88% better predictive value (PPV) when recognizing GY from sight, than a baseline system without deep learning and trained humans respectively. We evaluate six neural network architectures: AlexNet, GoogLeNet, Inception v3, ResNet-50, ResNet-101 and SqueezeNet. We find ResNet-50 to be the best compromise of accuracy and training cost. The trained neural networks, code to reproduce the experiments, and data of leaf clipping images are available on the internet. This work will advance the frontier of GY detection by improving detection speed, enabling a more effective response to the disease.

The agriculture industry is facing a crisis and must consider AI to reduce operational costs. One such area is pest and disease scouting. Delays cause further infection and growers must act quickly if a disease is discovered. However, scouting often requires external consultants and lab tests, time consuming and costly. Deep learning has the potential to detect diseases automatically from leaf clipping images. We achieve good results on two diseases of interest to the industry: Olive Quick Decline Syndrome (OQDS) and Grapevine Yellows (GY). The current challenge is overcoming data requirements of deep learning, often addressed with crowd sourcing. However, it can be difficult to crowd-source data of control pathogens. We demonstrate that it is possible to use data augmentation in place of crowd sourcing. The system has positive predictive values of 98.1% and 99.9% for detecting OQDS and GY respectively. Additionally, we discuss the potential for diagnosis-as-a-service, and open-source our data for greatest benefit to the AI community.

The aim of this investigation was to recover, characterize, and increase the value of local grapevine varieties from Garfagnana, a mountainous area situated in the north of Tuscany (located in central Italy). A total of 130 accessions (vines) were identified in old Garfagnana vineyards, characterized by Organisation Internationale de la Vigne et du Vin morphological-phenological and productive parameters, and genotyped with 14 microsatellite loci. The microsatellite analysis identified 50 genotypes. Some of these genotypes matched Tuscan genotypes, others corresponded to varieties cultivated in other Italian and European regions, and 18 appeared to be genotypes currently identified only in Garfagnana and presumably autochthonous to this area. Cluster and similarity analyses based on both microsatellite and morphology data indicated a clear grouping of the majority of the autochthonous genotypes from Garfagnana. A parentage analysis revealed that the Garfagnana autochthonous genotypes are highly first degree–related among each other, suggesting that Garfagnana is a distinct historical center of diversity of cultivated varieties. The data from all varieties have been entered into the Italian Vitis Database (www.vitisdb.it).

Diagnostic tests for grapevine viruses subjected to phytosanitary rules involve a heavy workload for plant protection services and laboratories. Propagation schemes enable nurseries, where mother plants (MPs) are cultivated, to be linked to batches of certified plants (CPs). This approach entails post-production checks of MPs once infection occurs in CPs. However, this traceability system is not tight and follow ups are demanding. This study assessed radio frequency identification (RFID) tagging of plants in terms of its ability to reduce laboratory workloads for nursery health checks. RFID-tagged plants (RFID-CPs) were produced from individually tagged MPs (RFID-MPs) or row-tagged MPs (RFID-ROW, a less expensive approach). In a 10-year case study, the health status of CPs and RFID-CPs were assessed and the occurrence of infections then led to health checks in MPs, RFID-MPs or RFID-ROWs. Laboratory workloads were evaluated by considering two sampling methods (single or pool sampling). Using single sampling, the workload was reduced by 93–98% in RFID-ROW or RFID-MP checks compared to the conventional approach. Considerable reductions in workload due to the tagging system (93–96%) were also observed using pool sampling. Traceability of CPs and MPs using RFID reduces laboratory workloads, and supports emergency measures that can be taken to stop any unsafe sales of plants after a virus outbreak.

Due to its complex epidemiological cycle, including several polyphagous insect vectors and host plants, and the absence of efficient control strategies, Bois Noir (BN) disease of grapevine is encroaching wider territories in the main viticultural areas worldwide. Molecular approaches allowed to increase the knowledge about its etiological agent (Bois Noir phytoplasma, BNp; ‘Candidatus Phytoplasma solani’ species), revealing interesting features concerning BNp population structure and dynamics and transmission routes in vineyard agro‐ecosystems. In the present study, a multilocus sequence typing approach (vmp1 and stamp genes) was utilised for describing the genetic diversity among BNp strain populations in 17 vineyards localised in two distinct geographic areas in Tuscany (central Italy). The results confirmed that BNp ecology in Tuscan vineyards is mainly associated to the bindweed‐related host system, and allowed the identification of 14 BNp vmp1/stamp genotypes. Interestingly, the prevalent genotype (Vm43/St10) was never found in grapevines outside of Tuscany. Moreover, statistical analyses showed significant differences between the composition of BNp strain populations identified in grapevines from north‐western and central‐eastern Tuscany. These results reinforce the hypothesis that distinct geographic areas, probably associated with different ecological niches, can drive the selection of BNp strains, also favouring the entrance of unusual ‘Ca. Phytoplasma solani’ genotypes in vineyards.

Bois noir (BN) is the most widespread disease of the grapevine yellows complex in the Euro-Mediterranean area. BN is caused by ‘Candidatus Phytoplasma solani’ (BNp), transmitted from herbaceous plants to grapevine by polyphagous insect vectors. In this study, genetic diversity among BNp strains and their prevalence and possible association with grapevine symptom severity were investigated in a Sangiovese clone organic vineyard in the Chianti Classico area (Tuscany). Field surveys over 2 years revealed a range of symptom severity on grapevine and an increase of BN incidence. A TaqMan allelic discrimination assay detected only tufB type b among BNp strains, suggesting the prevalence of the bindweed-related ecology. Nucleotide sequence analyses of vmp1 and stamp genes identified 12 vmp1 and 16 stamp sequence variants, showing an overall positive selection for such genes. The prevalent genotype was Vm43/St10, reported for the first time in this study and closely related to strains identified only in the French Eastern Pyrenees. BNp strains identified in the examined vineyard and mostly grouped in separate bindweed-related phylogenetic clusters showed statistically significant differences in their distribution in grapevines exhibiting distinct symptom severity. These results suggest the possible occurrence of a range of virulence within BNp strain populations in the Chianti Classico area.

Citrus tristeza closterovirus (CTV) has been found several times in the last decades in Italy, and plant protection services are involved in monitoring and surveillance. Although orchards linked to the citrus industry are well monitored, there is an underestimated risk of viruses or virus-like diseases in ornamental nurseries. Our aim was to modify a CTV monitoring program to include other viruses (Citrus variegation virus, CVV; Citrus psorosis virus, CPsV) and viroids (Citrus exocortis viroid, CEVd; Hop stunt viroid, HSVd; Citrus bent leaf viroid, CBLVd; Citrus dwarfing viroid, CDVd; Citrus bark cracking viroid, CBCVd). Ornamental mother plants were monitored for four years in 15 nurseries in two locations in central Italy using inexpensive multiplex RT-PCR protocols. CTV incidence was 1.6–13.5%, with an average distribution of 11.9%. The average incidence of CVV and CPsV was 6.3% and 2.7%, respectively. Higher CTV, CVV and CPsV incidences were observed in C. x paradisi, C. grandis and C. x clementina. The most widespread viroid identified was CEVd (32.9%), frequently observed in C. x limonia and C. limon. HSVd (10.5%), and CDVd (7.1%) were mostly found in C. x limonia. Lower infection rates were observed for CBLVd (2.0%) and CBCVd (1.4%). However, the nurseries’ response to the virus alert by the protection services was only partially effective. Although the CTV incidence was lower in nurseries re-checked after the initial detection, it was not eradicated from two nurseries out of three, and the occurrence of viroids was reduced in just one nursery. Given that dangerous viruses along with the concomitant spread of viroids have unfortunately become a fact of every day life, multiplex RT-PCR diagnoses are likely to play an increasing role in warning nursery managers of possible infections.

A survey of genetic diversity of “flavescence doree” (FD)-related phytoplasmas in grapevines, alders and clematis as well as alder-feeding leafhoppers was conducted in France, Hungary, Germany, Italy and Serbia. Genotyping was based on the housekeeping gene map and on the vmp genes encoding surface variable membrane proteins. Transmission assays of the phytoplasmas were performed with alder and/or grapevine-feeding leafhoppers. The study demonstrated that European alders constitute an original reservoir of FD phytoplasma by hosting a high diversity of FD-related phytoplasma genotypes, also present in non viticultural areas. The alder phytoplasmas grouping in Vmp-I cluster were transmitted by the Macropsinae O. alni, but were not compatible with the FD phytoplasma vector on grapevine the Deltocephalinae Scaphoideus titanus. The alder phytoplasmas in Vmp-II and-III clusters were transmitted by the Deltocephalinae Allygus spp. and Orientus ishidae. Such pre-existing phytoplasmas were compatible with S. titanus transmissibility and can be responsible for the emergence of FD phytoplasma epidemics in grapevine. VmpA proteins of cluster II better adhered to Euscelidius variegatus and S. titanus insect cells and midguts than those of cluster I. Such adhesins might play a key role in the adaptation to new vectors.

Sanitary selection and certification of olive cultivars require sensitive diagnostic methods and effective sanitation protocols. Although much attention has been paid in the past few years to the development of diagnostic tools for reliable virus identification, the need to define a common and standardized diagnostic protocol led to the implementation of a ring test among nine Italian diagnostic laboratories. A one-step RT-PCR protocol and different primer sets, targeting the most common olive viruses covered by phytosanitary rules, were tested in each laboratory, using the same batch of positive and healthy controls as well as the same amplification conditions and reaction components. The one-step RT-PCR, performed using several specific primer sets, was able efficiently to detect the target viruses in all laboratories. Furthermore, a one-step RT-PCR protocol was used successfully for the first time for detection of Tobacco necrosis virus (TNV) and Olive mild mosaic virus (OMMV). Results showed that all target viruses were not uniformly distributed in the canopy, and that at least two subsets of samples must be collected from each plant. This standardized protocol is now being used to produce nuclear stocks for 70 different Italian olive cultivars, in the framework of the national project OLVIVA, which involves 25 national research institutions.

The health status of the native grapevine Vitis vinifera subsp. sylvestris (Gmeli) Hegi in natural areas in Europe has received little attention. A survey was carried out on wild grapevines in Tuscany (Italy), where isolates of the Grapevine rupestris stem pitting virus (GRSPaV), Grapevine leafroll-associated virus 1 and 3 (GLRaV-1 and GLRaV-3) and Grapevine virus A (GVA) were detected. The complete coat protein (CP) region of these isolates was sequenced to investigate the relationship of the viral variants from Tuscan wild grapevines with isolates from different geographical origins. According to the phylogenetic analyses, GLRaV-1 and GLRaV-3 isolates from Tuscan wild grapevines clustered with isolates from cultivated grapevines with nucleotide sequence identities ranging from 66% to 87% and from 72.5% to 99% respectively, without any correlation between the distribution and geographical origin. Conversely, GRSPaV and GVA isolates clustered together with other Italian isolates from V. vinifera with nucleotide sequence identities ranging from 71.14% to 96.12% and from 73.5% to 92%, respectively. Our analysis of the whole amino acid sequences revealed a high conservation level for the studied proteins explained by a selective pressure on this genomic region, probably due to functional constraints imposed on CP, such as specific interactions with cellular receptors in the insect vectors necessary for successful transmission. In addition, analyses of genetic recombination suggest no significant point mutations that might play a significant role in genetic diversification. The dN/dS ratio also estimated a low number of non-silent mutations, highlighting the purifying selective pressure. The widespread distribution of the Rugose wood complex (GRSPaV and GVA associated disease) in comparison with the Grapevine Leafroll associated viruses (GLRaV-1 and -3) could explain the major geographical correlation found for the viral variants detected in Tuscany.

RFID sensors are effective for real-time temperature monitoring during solarization.Lesions of biodegradable film can be highlighted by RFID temperature assessment.Easy-to-use monitoring tools help the farmer to understand the thermal effect. Soil-borne pathogen and weed control can be achieved by soil solarization even if estimation of time treatment is difficult to assess. Thus, due to dependence to environmental conditions and the need to minimize the time of treatments, the implementation of monitoring tools may help in solarization managements, especially when biodegradable films were applied or weather condition are subjected to significant variation. Digitalization of data relative to plants thanks to RFID applications has been used for health or treatment monitoring, sample collecting and retrieving sanitary information: this paper presents the testing of RFID sensor application for soil solarization purposes. Different matrices were selected to assess RFID temperature sensors performances. Sandy, loam and clay soils with different moisture-holding capacity were selected for sensor burial. Sensors were covered by 5 or 10cm of fresh matrix and read immediately. Reliability was found to be more than 90% in all tested conditions, while higher failure in tag reading was recorded in clay soil at 90% of moisture-holding capacity (-7% of tag reliability). Soil solarization treatment was carried out as case of study during a period characterized by changeable weather using a biodegradable film. Data, expressed as thermal addition and temperature classes, collected continuously by sensors permitted to design real-time graphs that help the farmer to understand the thermal effect caused by treatment. Throughout the second and third week of treatments, Tmax at 5cm depth is increased by 9-13?C or 11-14?C compared to environment, respectively. Otherwise, Tmax at 10cm depth is increased by 7-9?C compared to environment throughout the second and third week, showing as sensors are able to collect temperature during solarization. The soil microbial community of soils treated with solarization exhibited a slight reduction of cumulative carbon metabolic activity compared to control (8.8% of reduction), while among 31 preselected carbon sources, the soil microbial communities were capable of utilizing up to 23 carbon source without difference between treatments. Unified Modeling Language activity diagrams for solarization management via digital sensors were designed and effects of biodegradable film on microbial population were observed. The integration of information technology solutions with new-generation biodegradable films may offer an interesting revaluation of soil solarization in actual farm organization.

When a Palearctic bacterium meets a Nearctic insect vector: genetic and ecological insights into the emergence of the grapevine ‘[i]Candidatus Phytoplasma vitis[/i]’ and ‘[i]Ca. P. vitialni[/i]’ epidemics in Europe. 25. International Congress of Entomology (ICE 2016)

To evaluate the role of purines in antiviral treatments in plants, ribavirin (RB) and tiazofurin (TZ) were applied in combination with guanosine (GS) or adenosine (AS) in in vitro grapevine or tobacco explants infected by Grapevine leafroll associated virus 3 (GLRaV-3) and Cucumber mosaic virus (CMV), respectively. Using a microelectrochemical (trans-plasma membrane electron transport, t-PMET) technique, in vivo assay of free reduced nicotinamide adenine dinucleotide (NADH) was also carried out to estimate the inosine monophosphate dehydrogenase inhibition caused by drugs. Antiviral effectiveness of TZ, evaluated as virus-free explants or virus copies, was significantly hindered by GS in both species, while AS did not interfere with the drugs. GS, but not AS, slightly hindered the antiviral effectiveness of RB. With regard to NADH tests, t-PMET inhibition caused by RB and TZ was dose dependent and the interference of drugs with the NAD+/NADH conversion was confirmed by NADH content. Findings indicate that exogenous GS up to 0.50 mM replenished the GS pool depleted by drugs, contrasting antiviral action. At higher doses of GS, the TZ antiviral action was completely inhibited and exogenous GS caused a feedback that reduced t-PMET activity. The reversal was partially against RB, suggesting that the reduction of the GS pool contributed to the antiviral activity of RB, but it was not the only cause of antiviral effectiveness.

International audience; Food contamination by toxic pesticides has induced intense research for alternative methods to control pests and diseases. For instance, the phasing out of methyl bromide used for soil disinfection has led to a reconsideration of heat-based methods to control soil-borne pathogens. Techniques such as soil steaming and soil solarization have been applied successfully. However, traditional steaming and solarization are unable to control viruses such as the Tobacco mosaic virus. Thus, methods for sustainable control of virus in soil are not available. Here, we tested the effect of short-duration soil steaming enhanced by the addition of exothermically reacting chemicals—potassium hydroxide or calcium oxide—and soil solarization. These methods were tested against three viruses having different stability: the highly stable Tobacco mosaic virus and the medium stable Potato virus Y, and the Cucumber mosaic virus as non-persistent control. Steaming was done in laboratory and open-field conditions after incorporation of exothermically reacting chemicals. Soils were solarized for 20 days using transparent polyethylene, ethylene–vinylacetate and high-effectiveness infrared films. Our results show that steaming with exothermic chemicals decreased the infectivity of the Tobacco mosaic virus below 3.0 %. We also found that the Tobacco mosaic virus was not controlled by solarization. The Potato virus Y was totally controlled by steam treatments and by soil solarization with ethylene–vinylacetate or high-effectiveness infrared films. Overall, our findings evidence promising ways to control soil viruses.

The results of the grapevine clonal selection carried out in Tuscany in the last seven years not only provided evidence of a high concentration of viral infections, but also showed that the sanitary status of the variety Aleatico is extremely worrying. The sanitary tests conducted on 172 plants, selected in the Elba Isle, on the hills around Lucca and in Maremma region showed a critical phytovirological condition. In fact, only 5 plants passed the first sanitary screening, being found free of all viruses investigated (GFLV, ArMV, GFkV, GLRaV-1, GLRaV-3, GLRaV-7, GVA and GVB). The candidate clones selected in Maremma showed remarkable differences in their morphological traits, both from one another ('ALESCA 59' and 'ALESCA 60' on one side, and 'ALCHI V on the other), and from those that had been identified on the Elba Isle ('ALE 102' and 'ALE 119'). The differences found among the 3 biotypes were statistically confirmed by cluster analysis procedures concerning the OIV traits of the shoots, leaves and bunches, and through the results of preliminary DNA analyses conducted in 6 micro-satellite loci. The general analysis of the available data showed the following decreasing scale of virus spreading values for the variety Aleatico (for the studied viruses): GLRaV-3>GLRaV-l>GVA>GFLV>GFkV. ArMV, GLRaV-7 and GVB have never been found. Differences in the infectious combinations ascertained in the 3 areas of selection are particularly interesting. The presence of mixed infections did not affect the vines that had been selected in the Maremma region and only slightly affected those from the Lucca hills, while 16 different combinations were found for the Elba Isle. The worrying sanitary status of Aleatico and the lack of registered clones of this variety seem to attach great importance to the results of this work, even if still quantitatively poor, for the improvement of the island's vine-growing activity along with the promotion of Aleatico wine, whose excellent organoleptic features and uniqueness are well-known.

SUMMARY The search for non-chemical methods to control soil-borne pathogens has recently intensified ahead of the forthcoming phase-out of the fumigant methyl bromide in 2005. Indeed, none of the previously available alternatives match methyl bromide wide-spectrum control. Here, we tested two pre-planting treatments: steaming with a soil-steaming machine and exothermic reaction by incorporation into the soil of potassium hydroxide (KOH), a substance that causes an exothermic reaction with water. Experiments were conducted from 2003 to 2005 in open-field conditions by assessing the effectiveness of steam and exothermic reaction against Fusarium oxysporum f.sp. basilici and Sclerotinia minor on basil. The results show that steam combined with exothermic reaction reduce the incidence of Fusarium wilt (77–96%) better than steam only (70–89%). The control of Sclerotinia minor was better with potassium hydroxide (94–92%) than with steam only (83–87%). Further, we evaluated the effects of the treatments on microbial population, yield and weed control. Here, the treatments induced the following major effects: (1) a reduction of more than 99% of the number of Fusarium oxysporum colonies in soil; (2) an increase of about 200% in Trichoderma spp. in soil; (3) a drastic increase in the plant yield, from 6.9–7.5 g for the control to 23.0–25.5 gr for steam treatments; (4) a high reduction of plants per square meter of 94–95% for Amaranthus retroflexus, of 96–99% for Portulaca oleracea, of 93–94% for Chenopodium spp. and of 86–90% for Hordeum vulgare, using both steam and exothermic reactions. Similar results were obtained with steam only. Therefore, our results evidence the potential of this approach to control various soil-borne pathogens. Steam and exothermic reaction are thus promising alternatives to chemical soil disinfestation for high-value crops.

In September 1999, several Spathiphyllum plants grown in a greenhouse in Tuscany (Italy) showed leaf symptoms in the form of concentric chlorotic ringspots, line patterns, and irregular chlorotic blotches. These symptoms developed into localized necrosis. Crude sap of tissues showing symptoms was mechanically inoculated to young symptomless Spathiphyllum plants and to Nicotiana benthamiana and N. clevelandii. Samples drawn from symptomatic and symptomless tissues of naturally or artificially infected Spathiphyllum and Nicotiana plants were tested for the presence of Alfalfa mosaic virus (AMV), Arabis mosaic virus (ArMV), Cucumber mosaic virus (CMV), Dasheen mosaic virus (DsMV), Impatiens necrotic spot virus (INSV), Potato X virus (PVX), Potato Y virus (PVY), Tobacco mosaic virus (TMV), and Tomato spotted wilt virus (TSWV) by double-antibody sandwich enzyme-linked immunosorbent assay carried out with commercial antisera. The symptomatic tissues obtained from Spathiphyllum and Nicotiana plants gave a positive reaction only for INSV. The symptomless samples obtained from various parts of the infected Spathiphyllum plants gave a negative reaction, even after 1 year from the appearance of localized necrosis, suggesting a non-systemic infection in this new host. This is the first report of infection of Spathiphyllum sp. by INSV.

Soil solarization reduced both recovery and viability ofSclerotinia minor sclerotia depending on the depth of burial. Highest reduction of these parameters was obtained at 4–6 cm depth (55%) and 0–2 cm depth (96%) respectively. Soil solarization accelerated the exponential decay of sclerotia observed in natural soil. In the upper 6 cm of soil this decay was so fast that after about 14 days loss of the sclerotial viability approached values recorded at the end of the treatment after 41 days. The number of sclerotia colonized by microorganisms is higher in solarized than in non-solarized plots.

In order to enhance the Italian lily bulb production, a breeding program was carried out at CRA-VIV in Pescia (PT – Italy) during the last years. Asiatic hybrids (Lilium × elegans Thunb.), lily cultivars and other native species were involved in the program. The obtained lily lines, which presented interesting traits, were preserved in a collection. After years of vegetative propagation, some of the new selections showed symptoms referable to viral infections. Virus diseases represent some of the most dangerous threats of Lilium, so the application of fast and effective diagnostic techniques for early detection is very important. The aim of the present study, in the frame of a phytosanitary survey of the lily collection, is to investigate the presence and incidence of Cucumber mosaic virus (CMV), Lilium symptomless virus (LSV), Lily mottle virus (LMoV) and two tospoviruses (Impatiens necrotic spot virus, INSV, and Tomato spotted wilt virus, TSWV). Among the 60 samples object of this study, infections by LSV and CMV were frequently observed. Also LMoV was detected in a smaller amount of samples. All of the samples were negative to INSV and TSWV.