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Many studies have been carried out to determine the performance of the energy dissipators proposed by different authors, mainly analyzing the hysteretic loops of loading and unloading. Likewise, the authors have sought to have simple, easy to manufacture and economical designs. Based on the above, the analysis of a passive bidirectional dry friction energy dissipator system is presented, whose main characteristic is the implementation of layer elements as structure, besides not requiring bolts or springs for the application of the preload. The study is carried out by means of numerical modeling using the finite element software Abaqus. The energy dissipation analysis is presented by means of hysteresis cycles, for different types of preload and number of stacked layer elements. The device, by means of one of the analyzed configurations, presents the capacity to dissipate 52 J of energy, being an innovative and functional design.

Colletotrichum ocimi causes black spot of basil (Ocimum basilicum) and is a serious threat to basil cultivation as it compromises leaf production. The pathogen also infects seeds, which could become primary sources of inoculum for spread of black spot. A SYBR Green real-time PCR assay was developed to detect Colletotrichum ocimi in basil leaves and seeds, based on the partial β-tubulin (tub2) gene sequence. Two primer sets were designed and tested. The selected primer pairs produced amplicons of 130 bp. The real-time PCR assay was validated for analytical specificity, sensitivity, selectivity, repeatability and reproducibility. The assay was specific for C. ocimi with respect to ten Colletotrichum spp. and to another 12 pathogens of basil plants. Sensitivity was 1 pg µL-1 of genomic fungal DNA and amplification analyses were not influenced by basil genomic DNA. The assay detected and quantified C. ocimi in artificially inoculated basil leaves. This is the first specific primer set for C. ocimi, which allows rapid detection and quantification of the pathogen is a useful tool for diagnostics in plants. Detection in seeds would also be possible, but will require an optimized extraction method. The qPCR detection of C. ocimi in planta can contribute to adoption of effective preventive disease management strategies.

Highbush blueberry is an increasingly important crop due to its economic value and demonstrated health benefits of blueberries. Leaf spots are considered as minor diseases of blueberry plants, but they adversely affect blueberry productivity, causing reduced photosynthetic activity, flower bud formation and berry production. Surveys of blueberry crops were conducted in Piedmont, Northern Italy, during 2019-2020. Fungi isolated from leaf spots of the blueberry cultivar ‘Blue Ribbon’ were identified as Colletotrichum helleniense through a robust multi-locus phylogeny. Eight genomic loci were considered: tub, gapdh, act, cal, his3, chs-1, ApMat and gs. Morphological characters of a representative strain were assessed. Pathogenicity was confirmed on four blueberry cultivars, although with different levels of aggressiveness to the cultivars. This study shows the importance of a polyphasic approach to investigate species of Colletotrichum, and the relevance of molecular tools for the species-level characterization within the ‘Kahawae’ clade. This is the first report of Colletotrichum helleniense causing leaf anthracnose on Vaccinium corymbosum.

Twelve trials, in closed soilless culture under controlled conditions, were carried out to evaluate the efficacy of resistance inducers (based on K-phosphite and K-silicate used alone or in combination), and of experimental biocontrol agents (Trichoderma sp. TW2, a mixture of Pseudomonas FC 7B, FC 8B, and FC 9B, Fusarium solani FUS25, Pseudomonas sp. PB26), and a commercial formulation of Trichoderma gamsii + T. asperellum, against diseases caused by Phytophthora capsici of sweet pepper. The products were applied using three different protocols, and effects on incidence of Phytophthora crown, stem and root rots (% dead plants), disease development (area under the disease progress curve; AUDPC), and plant fresh weights were evaluated. Potassium phosphite, applied directly at standard P2O5:K2O, 1.30 + 1.05 g L-1) and at half standard rates, onto growing media, or via nutrient solution, and before infestation of peat plant growing medium with P. capsici, provided the best disease management in a dose-dependent manner, with an 80% reduction of Phytophthora crown, stem and root rots for the standard dosage and for both types of application. These treatments also reduced proportions of dead plants by 47% from the standard rate and by 62% at the half standard rate, when applied via the nutrient solution or directly to the substrate. K-silicate alone partially reduced the percentage of dead plants, with efficacy of 20–23%. No improvement in disease control was observed when K-silicate was applied in combination with phosphite, while K-silicate alone or combined with K-phosphite reduced disease development, compared to untreated controls. Biocontrol agents (BCAs), applied preventively, reduced Phytophthora crown, stem and root rots, with similar or better results than those from the commercial mixture of Trichoderma asperellum + T. gamsii. Among the tested BCAs, Fusarium solani FUS25 provided the most consistent disease reduction (60–65%) and gave increased plant fresh weights. All the tested BCAs reduced disease development, with a similar trend for different disease pressures. The least AUDPC values, compared to the non-treated controls, were from Fusarium solani FUS25, followed by the tested Pseudomonas strains and Trichoderma sp. TW2. These results indicate the potential for potassium phosphite and biocontrol agents in management of Phytophthora crown, stem and root rots of pepper grown in soilless systems.

Potted plants of Mammillaria painteri (Cactaceae) showing symptoms of stem rot were collected from a nursery in Imperia province, Liguria region, Italy. Isolations from internal rotting tissues allowed gave constantly similar fungal colonies. Morphological characteristics of the isolates identified them as Fusarium oxysporum. Molecular analyses of the elongation factor 1α (EF1α) and RPB2 genes confirmed the identification. Analysis of part of the intergenic spacer (IGS) region of the ribosomal DNA identified the pathogen as F. oxysporum f. sp. opuntiarum. In pathogenicity tests, stems of M. painteri plants were inoculated with representative F. oxysporum f. sp. opuntiarum isolates. Approx. 30 d after the inoculation, yellowing appeared around the inoculated wounds. The inoculated stems then rotted developing symptoms similar to those observed in greenhouse-grown plants. This is the first report of F. oxysporum f. sp. opuntiarum on M. painteri.

Fusarium equiseti, a member of the Fusarium incarnatum-equiseti species complex (FIESC), has recently been reported in Italy as the causal agent of a leaf spot diseases on previously unrecorded plant hosts. This emerging disease has affected leafy vegetable hosts including lettuce, lamb’s lettuce, wild rocket, cultivated rocket, spinach and radish, and has caused symptoms that have not been previously described on those plants. Fifty-two fungal isolates obtained from symptomatic plants and different plant organs were identified according to their morphology as belonging to the FIESC. The present study aimed to characterize these isolates by identifying their FIESC phylogenetic species, and to evaluate their pathogenicity and host ranges. Six phylogenetically different species of FIESC were identified using MLST analyses of four loci (tef1, cmdA, tub2, and IGS). Most of the isolates were found to belong to F. compactum or F. clavum, while the other four FIESC species were represented by only a few isolates. All the fungal isolates were capable of inducing leaf spot diseases as single isolates with fulfilling Koch’s postulates for these fungi. The intraspecies diversity of the FIESC, the seed-originated isolates of four FIESC identified species, and enhanced range of experimental hosts were observed in the FIESC emerging diseases of these vegetable hosts in Italy. Strict seed inspection procedures, and suitable alteration of environmentally friendly fungicides and biological control agents should achieve efficient management of the FIESC leaf spot diseases on vegetable crops, and prevent further spread of these pathogens to new hosts and new geographical areas.

Phytophthora capsici Leonian (PHC) is a filamentous pathogen oomycete that causes root, fruit, foliar and crown rot over a wide host range, including the economically and nutritionally important summer squash (Cucurbita pepo var. cylindrica L.) crop. PHC chemical control strategies are difficult to adopt, due to the limited number of registered chemicals that are permitted and the scalar harvest system. For these reasons, other strategies, such as the use of waste-based composts that can act as suppressive agents against several soilborne pathogens, have been studied intensively. It is well known that compost’s microbiota plays an important role to confer its suppressive ability. In this study, four different composts were analyzed with both 16S rRNA gene and 18S rRNA gene real-time PCR amplification and with 26S gene amplicon-based sequencing; the total abundance of the bacterial and fungal communities was found to be higher compared to literature, thus confirming that the four composts were a good inoculum source for agricultural applications. The core mycobiota was mainly composed of 31 genera; nevertheless, it was possible to observe a clear predominance of the same few taxa in all the composts. The four composts were then tested, at different concentrations (1–10–20% v/v), to establish their ability to confer suppressiveness to the Phytophthora capsici (PHC) – Cucurbita pepo pathosystem in controlled greenhouse pot trials. A total of 12 compost mixtures were considered, and of these, one (Trichoderma-enriched compost at 10% v/v) was able to statistically reduce the disease incidence caused by PHC (by 50% compared to the untreated control). Hence, the microbiota composition of the most effective compost treatment was investigated and compared with untreated and chemical (metalaxyl) controls. Mycobiota sequencing showed genera differences between the three treatments, with relative abundances of several fungal genera that were significantly different among the samples. Moreover, PCA analyses clustered the compost treatment differently from the chemical and the untreated controls. These findings suggest that suppressive activity of a compost is strictly influenced by its microbiota and the applied dosage, but the ability to induce a shaping in the rhizosphere microbial composition is also required.

Effects of anaerobic soil disinfestation (ASD) on Rhizoctonia solani basal rot of lettuce were assessed considering: two soil types; different C-sources; different temperature regimes; two treatment durations; and two lettuce crop cycles, in the presence of a high disease incidence from artificial infestation with the pathogen. C-source, temperature, and incubation period, and their interaction, affected the efficacy of the ASD treatment for the lettuce–R. solani pathosystem, with differences depending on the soil type. Brassica carinata pellets, used as a C-source, reduced incidence of Rhizoctonia basal rot in the first crop cycle by 50 to 69% in a peat soil after 3 weeks of treatment at 21°C, and by 52 to 60% after 3 weeks of treatment at 26 or 31°C, compared to the inoculated and untreated experimental controls without anaerobic conditions. The best disease reduction was provided by B. carinata pellets applied, under anaerobic conditions, to peat soil (79% efficacy) and a sandy loam soil (100% efficacy) kept at 31°C for 6 weeks. Generally, ASD based on B. carinata pellets provided greater disease reduction in the first crop cycle than the second, with the only exception being for results achieved in both soils incubated for 6 weeks at 21, 26 and 31°C. Wild rocket used as a C-source provided the greatest disease reduction (78–83%) on plants grown in peat soil at the first crop cycle after 6 weeks of the ASD treatment at 31°C, while wild rocket provided disease reduction of 29 and 50% when mixed with the sandy-loam soil under the same conditions for 6 weeks. The efficacy of the ASD treatment with compost was improved in the second crop cycle, compared to the first, resulting in the greatest disease reduction (52 and 66% efficacy) reached in the sandy-loam soil incubated for 3 weeks at 21°C, and 63% efficacy in peat soil previously treated for 6 weeks at 26 and 31°C. However, slight reductions in lettuce plant development was generally evident in the first crop cycle, which could be due to differences in efficacy of the tested ASD treatments and to phytotoxicity. The greatest yield from sandy loam soil was obtained for the B. carinata pellets and wild rocket at 26 and 31°C in the second cultivation cycle. Partial efficacy of ASD does not justify the adoption of this method against R. solani on lettuce under intensive crop systems. However, ASD based on Brassicaceae and compost as carbon source applied in a sandy-loam soil may be valuable for reducing R. solani incidence, at lower temperatures than those required for soil solarisation or biosolarisation.

The effect of simulated climate changes by applying different temperatures and CO₂ levels was investigated in the Blumeria graminis f. sp. tritici/wheat pathosystem. Healthy and inoculated plants were exposed in single phytotrons to six CO₂+temperature combinations: (1) 450 ppm CO₂/18–22°C (ambient CO₂ and low temperature), (2) 850 ppm CO₂/18–22°C (elevated CO₂ and low temperature), (3) 450 ppm CO₂/22–26°C (ambient CO₂ and medium temperature), (4) 850 ppm CO₂/22–26°C (elevated CO₂ and medium temperature), (5) 450 ppm CO₂/26–30°C (ambient CO₂ and high temperature), and (6) 850 ppm CO₂/26–30°C (elevated CO₂ and high temperature). Powdery mildew disease index, fungal DNA quantity, plant death incidence, plant expression of pathogenesis-related (PR) genes, plant growth parameters, carbohydrate and chlorophyll content were evaluated. Both CO₂ and temperature, and their interaction significantly influenced powdery mildew development. The most advantageous conditions for the progress of powdery mildew on wheat were low temperature and ambient CO₂. High temperatures inhibited pathogen growth independent of CO₂ conditions, and no typical powdery mildew symptoms were observed. Elevated CO₂ did not stimulate powdery mildew development, but was detrimental for plant vitality. Similar abundance of three PR transcripts was found, and the level of their expression was different between six phytotron conditions. Real time PCR quantification of Bgt was in line with the disease index results, but this technique succeeded to detect the pathogen also in asymptomatic plants. Overall, future global warming scenarios may limit the development of powdery mildew on wheat in Mediterranean area, unless the pathogen will adapt to higher temperatures.

Severe outbreaks of Alternaria leaf spot have occurred in Northern Italy on leafy vegetable and ornamental hosts. This disease is mainly controlled by two classes of respiration inhibitor fungicides, QoIs (including azoxystrobin) and SDHIs (including boscalid). Thirty-six Alternaria strains were isolated from five leafy vegetable crops, and subjected to molecular characterization. Multilocus phylogenetic analyses assigned most of the strains (86%) to A. alternata, while the rest were A. arborescens and other Alternaria spp. In vitro sensitivity assays showed that 3% of the strains were of intermediate resistance, and 11% of reduced sensitivity to azoxystrobin, while 8% of the strains were resistant to boscalid. Sequencing of cytochrome b in an intermediately resistant strain of Alternaria revealed the G143A mutation. This strain was also resistant to boscalid. None of the tested Alternaria strains had amino acid mutations associated with boscalid resistance coded by the SdhB and SdhC genes. This is the first report of azoxystrobin resistance in A. alternata in Italy, as well as the first record of resistance of Alternaria spp. found on leafy vegetables. As boscalid resistance was not associated with any frequently reported mutations, further investigations of the additional resistance mechanisms are necessary. These results demonstrate the need for well-organized chemical control of emerging Alternaria diseases, to prevent the increase of resistance to QoI and SDHI fungicide classes, and the possibility of double fungicide resistance in these pathogens.

Black spot is a major foliar disease of sweet basil (Ocimum basilicum) present in a typical cultivation area of northern Italy, including the Liguria and southern Piedmont regions, where this aromatic herb is an economically important crop. In this study, 15 Colletotrichum isolates obtained from sweet basil plants with symptoms of black spot sampled in this area were characterized morphologically and by nuclear DNA analysis using internal transcribed spacers (ITS) and intervening 5.8S nrDNA as well as part of the β-tubulin gene (TUB2) regions as barcode markers. Analysis revealed all but one isolate belonged to the recently described species C. ocimi of the C. destructivum species complex. Only one isolate was identified as C. destructivum sensu stricto (s.s.). In pathogenicity tests on sweet basil, both C. ocimi and C. destructivum s.s. isolates incited typical symptoms of black spot, showing that although C. ocimi prevails in this basil production area, it is not the sole causal agent of black spot in northern Italy. While no other hosts of C. ocimi are known worldwide, the close related species C. destructivum has a broad host range, suggesting a speciation process of C. ocimi within this species complex driven by adaptation to the host.

In the recent years (2010–2016), leafy vegetables have been found to be hosts for many new diseases. The causal agents of these diseases had often been known on other crops, but have appeared for the first time throughout the world on several cultivated vegetable hosts such as: Lactuca sativa, Diplotaxis spp., Eruca sativa, Valerianella olitoria, Ocimum basilicum and Spinacia oleracea. This review considers pathogens such as Alternaria spp. on basil and rocket, Fusarium equiseti on lettuce, rocket and radish, and Myrothecium verrucaria and M. roridum on lamb’s lettuce, spinach and wild rocket. All these pathogens are seed-transmitted, a biological characteristic that raises the risk of worldwide dissemination. The role of climate change and globalization on the appearance of such diseases, and potential tools for their management under a climate change scenario, is discussed using leafy vegetables as a case study.

Fungi belonging to the genus Alternaria are common pathogens of fruit and vegetables with some species able to produce secondary metabolites dangerous to human health. Twenty-eight Alternaria isolates from rocket and cabbage were investigated for their mycotoxin production. Five different Alternaria toxins were extracted from synthetic liquid media and from plant material (cabbage, cultivated rocket, cauliflower). A modified Czapek-Dox medium was used for the in vitro assay. Under these conditions, more than 80% of the isolates showed the ability to produce at least one mycotoxin, generally with higher levels for tenuazonic acid. However, the same isolates analyzed in vivo seemed to lose their ability to produce tenuazonic acid. For the other mycotoxins; alternariol, alternariol monomethyl ether, altenuene and tentoxin a good correlation between in vitro and in vivo production was observed. In vitro assay is a useful tool to predict the possible mycotoxin contamination under field and greenhouse conditions.

Climate changes, particularly increases in temperature and CO2,are seriously challenging agriculture, and are one of the main factors that should be considered in the emergence of new diseases and their potential spread. Six trials were carried out to evaluate the effects of increased temperature and CO2 on the severity of leaf spot of lettuce, caused by Allophoma tropica (syn. Phoma tropica), a pathogen that was first observed on lettuce in northern Italy in 2011. Temperature, CO2 and their interactions were significant factors (P

Species of Colletotrichum are considered important plant pathogens, saprobes, and endophytes on a wide range of host plants. In Italy, several Colletotrichum species have been reported in glasshouse environments. In this study, we have explored the occurrence, diversity, and pathogenicity of Colletotrichum spp. associated with aromatic and ornamental plants belonging to the Lamiaceae family. Surveys were carried out during the 2011−2018 period in Liguria and Piedmont, Italy. A total of 19 Colletotrichum isolates were collected from symptomatic leaves and seeds of Ocimum basilicum (basil), Origanum vulgare (oregano) and different Salvia spp. A multi-locus phylogeny was established based on the basis of four genomic loci (ITS, GAPDH, ACT and TUB2). The aggressiveness of selected, representative isolates were tested. Colletotrichum isolates were identified as being members of three major species complexes: C. acutatum, C. destructivum, and C. gloeosporioides. Colletotrichum fioriniae, C. bryonicola, and C. fructicola were found in association with leaf lesions on Salvia leucantha, S. nemorosa, and S. greggii, respectively. Colletotrichum nigrum was isolated from twig lesions of S. greggii. Moreover, C. fioriniae and C. ocimi were found to be responsible for causing leaf anthracnose of oregano and basil, respectively. All the tested isolates were pathogenic and reproduced identical symptoms to those observed in commercial glasshouses. The present study improves our understanding of Colletotrichum species associated with several hosts belonging to the Lamiaceae family, which are cultivated extensively throughout Italy for different purpose, and provides information that may be useful for an effective disease management program.

The most common technique used to detect ochratoxin A (OTA) in food matrices is based on extraction, clean-up, and chromatography detection. Different clean-up cartridges, such as immunoaffinity columns (IAC), molecular imprinting polymers (MIP), Mycosep™ 229, Mycospin™, and Oasis® HLB (Hydrophilic Lipophilic balance) as solid phase extraction were tested to optimize the purification for red wine, beer, roasted coffee and chili. Recovery, reproducibility, reproducibility, limit of detection (LOD) and limit of quantification (LOQ) were calculated for each clean-up method. IAC demonstrated to be suitable for OTA analysis in wine and beer with recovery rate >90%, as well as Mycosep™ for wine and chili. On the contrary, MIP columns were the most appropriate to clean up coffee. A total of 120 samples (30 wines, 30 beers, 30 roasted coffee, 30 chili) marketed in Italy were analyzed, by applying the developed clean-up methods. Twenty-seven out of 120 samples analyzed (22.7%: two wines, five beers, eight coffees, and 12 chili) resulted positive to OTA. A higher incidence of OTA was found in chili (40.0%) more than wine (6.6%), beers (16.6%) and coffee (26.6%). Moreover, OTA concentration in chili was the highest detected, reaching 47.8 µg/kg. Furthermore, three samples (2.5%), two wines and one chili, exceeded the European threshold.

Plectosphaerella cucumerina that has recently been described as causing a leaf spot on wild rocket (Diplotaxis tenuifolia) in Italy, but has not yet been recorded on this host in other countries. This fungus has the potential to cause severe economic losses to the salad-producing industry, especially in Italy. This paper describes the development of a real-time PCR assay based on internal transcribed spacer (ITS) sequence, to aid diagnosis of this pathogen in culture and in plant material. The assay showed no cross reaction with closely related Plectosphaerella species or with 18 other commonly found fungi, and was able to detect 10 fg of Pa. cucumerina DNA per reaction. The assay was more specific than previously available molecular methods. A comparison of molecular and isolation methods indicated that the real-time PCR method is suitable for detection of the pathogen on plant material.

The Intergovernmental Panel on Climate Change in its recent fourth assessment report predicts that, because of higher concentrations of greenhouse gases in the atmosphere, until 2100 the global mean temperature would rise between 0.6 and 4°C, in combination with changes in precipitation and an increased frequency of extreme weather events. Despite this trend, the extent and mechanisms through which elevated CO2 affects plant diseases remain uncertain. Increases in CO2 and temperatures are also expected to induce complex effects on plant pathogens. Although re- 10 search on the effects of climate change continues to be limited, new tools are permitting to study the effects of climate variables on infection rates in the case of some pathosystems. The shortage of critical epidemiological data on individual plant diseases needs to be addressed using experimental approaches. A useful tool for such types of studies is represented by phytotrons. Hereby, a new phytotron typology, built with the specific aim of studying the effect of climate change on plant disease, is described. Beginning from a general plant overview, key mechanical and electrical systems are described (i.e. air temperature and relative humidity control, lighting and CO2 control system etc.) as environmental parameters and operation cycle are summarized. In particular both parameters which could be set and monitored and those measured and stored are reported. After a suitable testing period, several operation cycles were performed in order to assess the control system’s stability and to optimize the management of all systems involved and the first experimental trials were carried out. The effect of three different simulated climatic conditions: 450 ppm of CO2 with standard temperature (ranging from 18 to 24°C or 18 to 26°C), elevated CO2 (800 ppm) with standard temperature and elevated CO2 (800 ppm) with elevated temperature (4°C higher than standard) on the development of grape powdery and downy mildew were tested.

A collection of 356 isolates of Aspergillus spp. collected during 2006 and 2007 from grapevines in northern Italy were identified through Internal Transcribed Spacer based Restriction Fragment Length Polymorphism (ITS-RFLP) and tested for ochratoxin A (OTA) production. Restriction endonuclease digestion of the ITS products using the endonucleases HhaI, HinfI and RsaI, distinguished five different RFLPs. From each pattern, three samples were sequenced and the nucleotide sequences showed different species corresponding to Aspergillus niger, A. carbonarius, A. tubingensis, A. japonicus and A. aculeatus. By comparing the sequences of the ITS regions, also the uniseriate species A. japonicus and A. aculeatus could be differentiated by HinfI digestion of the ITS products. Among the aspergilli, A. niger was the major species associated with grapes during 2006 (57.4%), while A. carbonarius was the major species during 2007 (46.6%). All the strains of Aspergillus were tested for their ability to produce OTA on Yeast extract sucrose medium (YES), as it was tested as an optimal substrate for the evaluation of OTA production by black aspergilli. Out of 356 isolates, 63 (17.7%) isolates produced OTA ranging from 0.05 to 3.0 µg mL−1. Most of the ochratoxigenic isolates were A. carbonarius (46) in both years, but also some strains of A. tubingensis (11) and A. japonicus (6) produced lower amounts of OTA.

Chestnut drying is used to prevent postharvest losses and microorganism contamination during storage. Several studies reported the contamination by aflatoxins (AFs) produced by Aspergillus spp. in chestnuts. The effect of drying temperatures (from 30 to 50 °C) was evaluated on the growth of A. flavus and the production of aflatoxins in chestnuts. The influence of the treatment on the proximate composition, the total phenol content and antioxidant activity of chestnuts was considered. Fungal colonization was observed on the nuts dried at 30, 35, and 40 °C; the incidence was lower at 40 °C. The highest concentrations of AFB1 and AFB2 were produced at 40 °C. No aflatoxins were detected at 45 or 50 °C. At 40 °C A. flavus was under suboptimal conditions for growth (aw 0.78), but the fungus was able to synthesize aflatoxins. As the temperatures applied increased, the total phenol content increased, while the antioxidant activity decreased. A drying treatment at 45 °C for seven days (aw 0.64) could be a promising method to effectively control both the growth of aflatoxigenic fungi and the production of aflatoxins. This study provides preliminary data useful to improve the current drying conditions used in chestnut mills, to reduce both fungal growth and aflatoxin production.

analysis based on the ITS region confirmed the pathogen as Fusarium oxysporum. In order to identify the forma specialis, thirteen isolates obtained from infected tissues were used for phylogenetic analysis based on four polygalacturonase genes (Pg1, Pg5, Pgx1 and Pgx4) together with the translation elongation factor 1-alpha (EF-1alpha) gene. Sequences generated in this study were aligned with other formae speciales of Fusarium oxysporum from GenBank to construct phylogenetic trees. Eleven isolates of a new forma specialis, Fusarium oxysporum f. sp. crassulae described on Crassula ovata, were added to the analysis based on Pg5 and Pgx1 genes. The results obtained for each genomic region showed that the isolates derived from E. agavoides are in a unique group well separated from other formae speciales already described. The first report of F. oxysporum on E. agavoides together with the results obtained in this study suggest a new forma specialis, here named F. oxysporum f. sp. echeveriae.

Symptoms of a new vascular wilt were observed on several plants of Papaver nudicaule cultivated at the Regional Institute for Floriculture in Sanremo and in a nursery near Ventimiglia, Liguria region, Northern Italy. Morphology and ITS sequence analysis characterize the pathogen as Fusarium oxysporum. To identify the forma specialis, eight isolates obtained from infected tissues were used for a phylogenetic analysis based on translation elongation factor 1-α (EF-1α) gene and four polygalacturonase genes (Pg1, Pg5, Pgx1 and Pgx4). After amplification by PCR, the gene sequences were aligned with corresponding sequences from other formae speciales of Fusarium oxysporum obtained from GenBank databases in order to build phylogenetic trees. Results obtained for each genomic region showed that the isolates derived from P. nudicaule form a unique group well separated from other formae speciales. To our knowledge, this is the first report of F. oxysporum on P. nudicaule and together with the phylogenetic analysis and positive pathogenicity tests permits us to introduce a new forma specialis named F. oxysporum f. sp. papaveris.

The efficacy of thyme and savory essential oils were investigated against Botrytis cinerea on apple fruit. Apples treated with thyme and savory essential oils showed significantly lower gray mold severity and incidence. Thyme essential oil at 1% concentration showed the highest efficacy, with lower disease incidence and smaller lesion diameter. The expression of specific pathogenesis-related (PR) genes PR-8 and PR-5 was characterized in apple tissues in response to thyme oil application and B. cinerea inoculation. After 6 h of pathogen inoculation, thyme essential oil induced a 2.5-fold increase of PR-8 gene expression compared to inoculated fruits. After 24 h of inoculation, PR-8 was highly induced (7-fold) in both thyme oil-treated and untreated apples inoculated with B. cinerea. After 48 h of inoculation, PR-8 expression in thyme-treated and inoculated apples was 4- and 6-fold higher than in inoculated and water-treated apples. Neither thyme oil application nor B. cinerea inoculation markedly affected PR-5 expression. These results suggest that thyme oil induces resistance against B. cinerea through the priming of defense responses in apple fruit, and the PR-8 gene of apple may play a key role in the mechanism by which thyme essential oil effectively inhibits gray mold in apple fruit.

The severity of F. oxysporum f.sp. conglutinans on rocket plants grown under simulated climate change conditions has been studied. The rocket plants were cultivated on an infested substrate (4 log CFU g-1) and a non-infested substrate over three cycles. Pots were placed in six phytotrons in order to simulate different environmental conditions: 1) 400-450 ppm CO2, 18-22°C; 2) 800-850 ppm CO2, 18-22°C; 3) 400-450 ppm CO2, 22-26°C, 4) 800-850 ppm CO2, 22-26°C, 5) 400-450 ppm CO2, 26-30°C; 6) 800-850 ppm CO2, 26-30°C. Substrates from the infested and control samples were collected from each phytotron at 0, 60 and 120 days after transplanting. The disease index, microbial abundance, leaf physiological performances, root exudates and variability in the fungal profiles were monitored. The disease index was found to be significantly influenced by higher levels of temperature and CO2. Plate counts showed that fungal and bacterial development was not affected by the different CO2 and temperature levels, but a significant decreasing trend was observed from 0 up to 120 days. Conversely, the F. oxysporum f.sp. conglutinans plate counts did not show any significantly decrease from 0 up to 120 days. The fungal profiles, evaluated by means of polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), showed a relationship to temperature and CO2 on fungal diversity profiles. Different exudation patterns were observed when the controls and infested plants were compared, and it was found that both CO2 and temperature can influence the release of compounds from the roots of rocket plants. In short, the results show that global climate changes could influence disease incidence, probably through plant-mediated effects, caused by soilborne pathogens.

Five trials were carried out under greenhouse conditions to test the efficacy of spray programmes based on biocontrol agents, phosphite-based fertilizers and a chemical inducer of resistance (acibenzolar-S-methyl, phosethyl-Al) to control crown and root rot of tomato incited by Phytophthora nicotianae. The best disease control, under high disease pressure resulting from artificial inoculation, was obtained with three pre-plant leaf sprays at 7 d intervals with acibenzolar-S-methyl and with two mineral phosphite-based fertilizers. The disease reduction achieved was similar to that obtained with a single application of azoxystrobin and metalaxyl-M. Phosetyl-Al and the biocontrol agents Glomus spp. + Bacillus megaterium + Trichoderma, B. subtilis QST713, B. velezensis IT45 and the mixture T. asperellum ICC012 + T. gamsii ICC080 provided a partial disease control. Brassica carinata pellets did not control the disease.

Before planning the large-scale use of nonpathogenic strains of Fusarium oxysporum as biocontrol agents of Fusarium wilt, their behaviour and potential impact on soil ecosystems should be carefully studied as part of risk assessment. The aim of this work was to evaluate the effects of antagonistic F. oxysporum strains, genetically manipulated (T26/6) or not (233/1), on soil microbial biomass and activity. The effects were evaluated, in North-western Italy, in two soils from different sites at Albenga, one natural and the other previously solarized, and in a third soil obtained from a 10-year-old poplar stand (Popolus sp.), near Carignano. There were no detectable effects on ATP, fluorescein diacetate hydrolysis, and biomass P that could be attributed to the introduction of the antagonists. A transient increase of carbon dioxide evolution and biomass C was observed in response to the added inoculum. Although the results showed only some transient alterations, further studies are required to evaluate effects on specific microorganism populations.

Aflatoxins, produced by Aspergillus flavus and A. parasiticus, can contaminate different foodstuffs, such as nuts. Cold atmospheric pressure plasma has the potential to be used for mycotoxin detoxification. In this study, the operating parameters of cold atmospheric pressure plasma were optimized to reduce the presence of aflatoxins on dehulled hazelnuts. First, the effect of different gases was tested (N2, 0.1% O2 and 1% O2, 21% O2), then power (400, 700, 1000, 1150 W) and exposure time (1, 2, 4, and 12 min) were optimized. In preliminary tests on aflatoxin standard solutions, this method allowed to obtain a complete detoxification using a high power for a few minutes. On hazelnuts, in similar conditions (1000 W, 12 min), a reduction in the concentration of total aflatoxins and AFB1 of over 70% was obtained. Aflatoxins B1 and G1 were more sensitive to plasma treatments compared to aflatoxins B2 and G2, respectively. Under plasma treatment, aflatoxin B1 was more sensitive compared to aflatoxin G1. At the highest power, and for the longest time, the maximum temperature increment was 28.9 °C. Cold atmospheric plasma has the potential to be a promising method for aflatoxin detoxification on food, because it is effective and it could help to maintain the organoleptic characteristics.

Effects of increased CO2 and temperature on powdery mildew (Podosphaera xanthii) of zucchini (Cucurbita pepo), were evaluated under controlled conditions. Zucchini plants were grown in phytotrons under four different simulated climatic conditions: 450 ppm of CO2 at standard (18°C night, 24°C day) and elevated temperatures (22°C night, 28°C day), elevated CO2 (800 ppm) with standard temperature and elevated CO2 (800 ppm) with elevated temperature (4°C higher than standard). Physiological responses of zucchini and pathogen development were studied. Under elevated CO2 both healthy and infected zucchini plants grew better when temperature was lower. Elevated CO2 generally caused no significant differences in pathogen development or disease severity, whereas elevated temperature stimulated the development of the pathogen. A combination of elevated CO2 and temperature always stimulated the development of the pathogen and disease severity compared to standard conditions.

Sclerotinia homoeocarpa F.T. Bennett is one of the most important pathogens affecting high maintenance turfgrass in Italy. Control of this pathogen still relies on the use of fungicides. Twenty nine isolates of S. homoeocarpa collected from 13 different golf courses in northern and central Italy were tested in vitro for their sensitivity to propiconazole, tebuconazole and iprodione, fungicides registered for use on turfgrass in Italy. Three isolates from untreated turfgrasses were use as reference isolates. The tests were carried out on an agar medium amended with 0, 0.01, 0.03, 0.1, 0.3, 1, 3, 10, 30, 100, 300 µg mL–1 of the active ingredient of each fungicide. Most of the isolates showed reduced sensitivity to the tested fungicides, while maintaining their virulence when inoculated on potted Agrostis stolonifera L. Fungicide resistance in this pathogen has increased in Italy compared with the situation 10 years previously.

In recent years a postharvest disease of kiwifruit, characterized by skin pitting appearing after 3 or more months of storage, and caused by C. luteo-olivacea, has been reported in most Italian packinghouses. Forty-four strains isolated from kiwifruit harvested in Italy during the period 2001-2009 were tested for their pathogenicity on kiwifruit, apple and pear. The pathogenicity tests showed that different isolates of C. luteo-olivacea were pathogenic on the three fruit species stored at 1°C for 120 days with various degree of virulence. A PCR-based method to identify the pathogen species in kiwifruit was developed. Sequencing of the internal transcribed spacer (ITS1, 5.8S gene and ITS2) region of the rDNA (ITS) showed high similarity with the species C. malorum, agent of side rot of apples and pears. Variation within the ITS was used to design one reverse primer common to both species and two species specific forward primers to specifically identify isolates of C. luteo-olivacea and C. malorum. Both SCAR (sequence characterized amplified region) primer pairs showed to be specific for either Cadophora species when cross-tested and assessed on other species of Cadophora or on species of typical postharvest pathogens of kiwifruit, apple and pear.

The effect of silicon on powdery mildew, caused by Oidium neolycopersici, was evaluated in five trials using two cultivars of tomato, ‘Ikram’ or ‘Cuore di bue’, grown in hydroponic systems. Silicon, as potassium silicate, was added at 100 mg L-1 of nutrient solution at three levels of electrical conductivity; 1.8–2 mS cm-1 (EC1), 3.9–4 mS cm-1 (EC2, 0.87 g L-1 NaCl) and 5–5.5 mS cm-1 (EC3, 1.74 g L-1 NaCl). Tomato plants were first inoculated with O. neolycopersici conidia 15–20 days after transplanting, with a maximum of five inoculations before final disease assessment. Drip or sub-irrigation methods, compared in two of the five trials, did not affect powdery mildew incidence and severity on leaves, 60 or 90 days after the first inoculation. The addition of NaCl to the nutrient solution generally reduced the incidence and severity of powdery mildew, with 0.87 or 1.74 g L-1 NaCl providing a similar effects. The addition to the nutrient solution of potassium silicate resulted in a signifi cant reduction of powdery mildew incidence and severity at the EC2 conductivity tested in all trials. The addition of potassium silicate to the control nutrient solution resulted in a similar or better level of powdery mildew management than the use of a nutrient solution with higher conductivity but no added with potassium silicate. The possibility and benefits of applying potassium silicate amendments in practice are discussed.

Twenty-nine strains of Fusarium oxysporum isolated from wilted lamb’s lettuce plants (Valerianella olitoria) along with eight ATCC reference strains were examined for differences in the nucleotide sequences of the ribosomal DNA (rDNA) intergenic spacer (IGS) region, which is about 2.5 kb long in these strains. A phylogenetic (neighbour-joining) analysis was performed on the strains and identified four phylogenetic groups, I, II, III, and IV. Most F. oxysporum isolates recovered from wilted lamb’s lettuce plants cultivated in northern Italy clustered in group I and were very similar to F. oxysporum f. sp. raphani. All the isolates, including the 8 control strains, were tested for pathogenicity on lamb’s lettuce cv. Trophy cultivated in the glasshouse. Most isolates from northern Italy were pathogenic on lamb’s lettuce, displaying varying degrees of virulence, and their IGS sequence were similar to the forma specialis raphani. However, four isolates were not pathogenic on lamb’s lettuce. Among the control strains, six showed moderate virulence; these belonged to the formae speciales raphani and conglutinans; and two, belonging to the forma specialis matthioli (ATCC16602 and ATCC16603) were not pathogenic on lamb’s lettuce. In conclusion, analysis of the IGS sequences indicated that the isolates studied had different origins, and that phylogeny and pathogenicity were related; non-pathogenic isolates differed genetically from isolates that were poorly, moderately or highly virulent. To the best of our knowledge, this is the first report on the differences between formae speciales of F. oxysporum on lamb’s lettuce plants as determined by IGS sequence analysis.

Fusarium crown and root rot (FCRR) of tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici is a serious problem in agriculture today. Biological control of this disease may be an effective option to deal with this problem. Antagonistic bacteria isolated from suppressive substrates or soils were tested against FCRR in the glasshouse in a sandy soil mixture infested with the pathogen and compared with other experimental or commercial FCRR biocontrol agents. The antagonistic bacteria were applied twice before artificial infection with the pathogen. Pseudomonas sp. strain FC-24B and P. putida FC-8B provided the best and most effective suppression in all trials, reducing vascular discoloration significantly from 65 to 77% and from 52 to 100% respectively. These strains also reduced root rot by 66% and 70% respectively. Pseudomonas sp. FC-24B also substantially increased plant growth, when the pathogen was absent. Pseudomonas sp. FC-9B, Achromobacter xylosoxydans MM1, Streptomyces griseoviridis strain K61 and the commercial formulation Trichoderma harzianum ICC012 + T. viride ICC080 also gave promising results in terms of disease control.

Aspergillus carbonarius colonizes grapes and its derived products and produces ochratoxin A (OTA). In previous studies we screened 107 strains of A. carbonarius isolated from grapes for production of OTA, and we selected three high OTA-producing strains for this study (AC05, AC06, and AC07). The effect of different values of three conditions [temperature 15, 25, 30, 35°C; water activity (aw) 0.98, 0.95, 0.90, 0.88; and pH 4.0, 7.0, 9.0, 10.0] on A. carbonarius growth and OTA production was examined. A. carbonarius AC07 produced higher levels of OTA than AC06 and AC05 at all the variables tested. At 30°C the strains of A. carbonarius produced more OTA than at the other temperatures. A water activity of aw 0.98 produced the greatest mycelial growth and OTA accumulation for all three A. carbonarius strains. A pH of 4.0 produced the highest levels of OTA in all the strains. No growth was seen at aw 0.88 or at pH 10.0 in any strain, except AC07, which grew at pH 10.0. The optimal conditions for growth and production of OTA by A. carbonarius strains were 30°C, aw 0.98 and pH 4.0. When all the three factors (aw, pH, T) were combined, aw 0.98, pH 4.00 and 30ºC produced the highest levels of OTA in all the strains. Maximum amounts of OTA were found 7–9 ays after inoculation in all the strains. Temperature, water activity, and pH had a great impact on OTA production by A. carbonarius and these factors should be taken into account when developing management practices for future research programmes.

Several commercial vineyards, located in Piedmont (Northern Italy), were monitored in order to evaluate the sensitivity of Botrytis cinerea Pers., the causal agent of grey mould, to five classes of botryticides: benzimidazoles, dicarboximides, phenylcarbamates, anilinopyrimidines and phenylpyrroles. Strains of B. cinerea resistant to anilinopyrimidines were easily detected, particularly in 1999, a year characterized by high disease pressure, even in vineyards not sprayed with that class of fungicides. Fludioxonil-resistance, on the contrary, was not detected. Resistance to benzimidazoles and dicarboximides was at previous observed levels. For the first time, resistance to phenylcarbamates was detected in the field. Strains of B. cinerea showing multiple resistance to benzimidazoles, dicarboximides and anilinopyrimidines and maintaining a good level of virulence, as shown by tests carried out on wounded apples, are present in Italian vineyards. Strategies in the use of the botryticides are discussed, in order to avoid a loss of disease control.

The influence of cultural practices on the incidence of root rot of lavender (Lavandula officinalis L.), caused by Phytophthora nicotianae var. parasitica was evaluated in two trials carried out in 1996 and 1997. The effects of type of substrate, type of pot and cultivation site (open field or under shade) were evaluated on lavender plants grown in soils with and without artificial inoculation with the pathogen. Growing plants under shade significantly reduced disease incidence in both seasons. Plants in larger pots had lower disease incidence, irrespective of type of substrate, or the presence or absence of soil inoculation. The data obtained in this study highlight the importance of light, soil temperature and pot volume in the epidemiology of P. parasitica on lavender.

Seven glasshouse experiments were set up in 1995–1999 to evaluate the efficacy of various treatments in reducing the incidence of “stanchezza” (soil sickness) of sweet basil, an emerging phytopathological problem in the main basil-growing areas of Italy. Complete or partial replacement of the soil was generally effective in increasing plant size and fresh weight of both roots and aerial parts. Steam disinfestation of the soil abolished the symptoms of “stanchezza” during the first growth cycle, but its effect was reduced on the second crop. Leaching the substrate with water and deep tilling had no or only limited effect on plant growth. Amendment with a commercial biostimulating product containing organic phenolic compounds had only partial efficacy. Bench solarization was the most effective means of control of the syndrome and its effect continued for the second crop cycle. No significant reduction of “stanchezza” was achieved with broad-spectrum antibiotic or fungicide mixtures. No significant differences were detected between bacterial and fungal populations in a soil with “stanchezza” and a non-cultivated soil. Further investigation is now required to shed light on the mechanisms underlying this emerging phytopathological problem.