Rot Infection Research Articles

A novel six-phage cocktail reduces Pectobacterium atrosepticum soft rot infection in potato tubers under simulated storage conditions

Pectobacterium atrosepticum is a species of plant pathogenic bacteria responsible for significant losses in potato production worldwide. Pectobacterium atrosepticum can cause blackleg disease on potato stems as well as the tuber disease termed potato soft rot. Methods for the effective control of these diseases are limited and are primarily based on good agricultural practices. Bacteriophages, viruses of bacteria, could be used as an alternative, environmentally friendly, control measure. Here, we describe the isolation and characterization of 29 phages virulent to P. atrosepticum. The phages belong to 12 different species based on a 95% sequence identity cut-off. Furthermore, based on sequence diversity and propagation results, we selected six of these phages to form a phage cocktail. The phages in the cocktail was tested on a number of P. atrosepticum strains in order to determine their host range. The phages was found to lyse 93% of the tested strains. The cocktail was subsequently tested for its effectiveness in combatting potato soft rot under simulated storage conditions. Use of the phage cocktail reduced both disease incidence and disease severity by 61% and 64%, respectively, strongly indicating that phage biocontrol has the potential to reduce the economic impact of soft rot in potato production.

Reducing apple scab and frogeye or black rot infections with salicylic acid or its analogue on field-established apple trees

Apple scab (Venturia inaequalis) (AS) and frogeye leaf spot or black rot (Botryosphaeria obtusa) (FLS or BR) are two diseases of apples that affect developing foliage and fruit during summer and cause significant losses in the field and during storage. In this 3-year study (2014–2016), salicylic acid (2-hydroxybenzoic acid) or its analogue (Benzothidiazole or Actigard®) were applied to field-established apple ‘Honeycrisp’ at the tight cluster stage of flower bud development and at late pink bloom as either trunk injection or foliar sprays and to ‘Cortland’ (injection only). AS and FLS leaf infections were assessed 1, 2, and 3 weeks after the second treatment while infections on fruit were assessed at harvest. Main treatment effects were significant (P = 0.05) and both salicylic acid and Actigard® showed less infections on foliage due to AS in 2014 and 2016, and only salicylic acid showed less BR infections on fruit in both years. The cultivar effects were also significant, showing consistently less AS infections on the foliage and fruit of ‘Honeycrisp’, and less FLS infections on ‘Cortland’ foliage. Injection and spray treatments of salicylic acid and Actigard® showed no differences in infections by AS and FLS or BR on foliage or fruit. The method of application × treatment interactions were only significant in 2014; both salicylic acid and Actigard®-treated ‘Cortland’ trees showed less FLS infections on foliage and less BR infections on fruit, and only salicylic acid-treated ‘Honeycrisp’ trees showed less percentage of AS and BR infected fruit. In 2015, both salicylic acid and Actigard® treatments showed less infections of FLS on foliage and lower BR-infected fruit on ‘Cortland’. In 2016, both these treatments reduced incidence of AS and FLS on ‘Cortland’ foliage, and only salicylic acid reduced AS infections on ‘Honeycrisp’ foliage. Further studies are needed to integrate salicylic acid or Actigard® treatments into an apple foliar disease management program with registered fungicides.

Application of Agriculturally Important Microorganisms for Biocontrol of Root Rot Infection of Sugar Beet

The roots rot of sugar beet caused by the soil-borne phytopathogenic fungi genera Fusarium and Alternaria are serious causes yield loss in the world. In this study, the antagonistic cellulolytic bacteria were isolated from the rhizosphere of sugar beet plants. The cellulase, antifungal, and growth-promoting activities of strains were examined, and one strain Bacillus cytaseus C-82 was selected. When C-82 was tested for its fungal inhibition and biological control activity under field conditions against root rot of sugar beet, it significantly reduced the disease and increased sugar beet yields by 30–34 c/ha relative to the untreated control plants.

A novel six-phage cocktail reducesPectobacterium atrosepticumsoft rot infection in potato tubers under simulated storage conditions

Pectobacterium atrosepticum is a species of plant pathogenic bacteria responsible for significant losses in potato production worldwide. Pectobacterium atrosepticum can cause blackleg disease on potato stems as well as the tuber disease termed potato soft rot. Methods for the effective control of these diseases are limited and are primarily based on good agricultural practices. Bacteriophages, viruses of bacteria, could be used as an alternative, environmentally friendly, control measure. Here, we describe the isolation and characterization of 29 phages virulent to P. atrosepticum. The phages belong to 12 different species based on a 95% sequence identity cut-off. Furthermore, based on sequence diversity and propagation results, we selected six of these phages to form a phage cocktail. The phages in the cocktail was tested on a number of P. atrosepticum strains in order to determine their host range. The phages was found to lyse 93% of the tested strains. The cocktail was subsequently tested for its effectiveness in combatting potato soft rot under simulated storage conditions. Use of the phage cocktail reduced both disease incidence and disease severity by 61% and 64%, respectively, strongly indicating that phage biocontrol has the potential to reduce the economic impact of soft rot in potato production.

Pathogenic Fusarium oxysporum f. sp. cepae growing inside onion bulbs emits volatile organic compounds that correlate with the extent of infection

Diseases develop during the storage of onions. To minimize losses, new methods are needed to identify diseased bulbs early in storage. Volatile organic compounds (VOCs), the respiration rate, weight loss, and the dry matter content were investigated for 1–7 weeks post inoculation of bulbs with water (control) and two strains (Fox006 or Fox260) of Fusarium oxysporum f. sp. cepae. Photos, multispectral image analysis, and real-time polymerase chain reaction (PCR) showed no infection in the control onions, weak pathogenic infection in Fox006-onions, and strong pathogenic infection in Fox260-onions at week 7 post inoculation. Infected bulbs exhibited increased respiration rate, increased VOC emission rate, and increased weight loss. The control and Fox006-onions did not respond to inoculation and had similar reaction pattern. Forty-three different VOCs were measured, of which 17 compounds had sulfur in their chemical structure. 1-Propanethiol, methyl propyl sulfide, and styrene were emitted in high concentrations and were positively correlated with the extent of infection (r = 0.82 – 0.89). Therefore, these compounds were the most promising volatile markers of Fusarium basal rot infection. For the first time, we show that the extent of fungal infection determined by real-time PCR in onion bulbs is related with VOC emission.

Biocontrol measures against onion basal rot incidence under natural field conditions

Laboratory and field experiments were carried out to evaluate the efficacy of the bio-agents Trichoderma harzianum, T. viride, Bacillus subtilis and Pseudomonas fluorescens and of the fungicide Carbendazim 50WP against onion basal rot caused by Fusarium oxysporum f. sp. cepae. The tested agents were found to be effective in vitro against F. oxysporum f. sp. cepae. The maximum growth inhibition of the fungal pathogen was induced by T. viride (95.5%) and T. harzianum (92.6%) followed by P. fluorescens (88.3%) and B. subtilis (79.3%), respectively. The fungicide Carbendazim 50WP caused a growth reduction of 85.7% at the concentration of 50 ppm. Complete inhibition of pathogen growth (100%) was recorded at 100 ppm. Under field conditions throughout two successive growing seasons, onion transplants immerged in a cell or spore suspension of P. fluorescens and T. viride showed the highest disease reduction, i.e. 69.5 and 61.8%, followed by 53.8, and 53.7% induced by B. subtilis and T. harzianum, respectively. Meanwhile, 22.2% disease reduction over the untreated control was induced by carbendazim 50WP. It can be concluded that the candidate bioagents could be utilized as options alternative to chemical fungicides for the management of basal rot infection of onion, also because they have v advantage of promoting soil fertility.

White rot of sunflower

Goal. To study the spread and development of white rot on sunflower in the Right bank of Forest-Steppe of Ukraine.
 Methods. The research was conducted during 2014—2018 in the forest-steppe zone of Ukraine (Kyiv and Khmelnytsky region). The selection of plant samples was carried out with further analysis in laboratory conditions The observations were conducted according to generally accepted methods; spread and severity of diseases were determined.
 Results. During the years of investigation, the root, stem and head types of the disease have been identified. There were significant differences in both the symptoms and the degree of disease development in different years. During the vegetative periods of 2014, 2015, and 2017 disease development was compiled — 2—5%. Symptoms of the disease were detected on the stems of plants and heads, starting with the phase of seed development — milk ripeness. The weather conditions of 2016 and 2018 (GTK in June-July 1.2—1.9) were favorable for white rot infection. The disease appeared from the phase of “star” in 2016 and at the beginning of flowering in 2018. The development of the disease was significantly higher compared to other years and reached 12.0—15.1% in 2016 with the spread of 61.2—75.0%. In 2018 its severity in Khmelnitsky region was 11.2% while spread reached 78.6%. Firstly, the root and stem, and later the head form of the disease were marked. In addition to the typical symptoms, spots with brown concentric circles were found on the basal part of the stem. At the same time, the tissue almost did not collapse, and small sclerotic could be detected only in its lower part.
 Conclusions. Under favorable weather conditions, white rot of sunflower is becoming widespread and may be epiphytotic. In the conditions of the Right bank of Forest-Steppe Ukraine, the disease occurs at different stages of organogenesis. Symptoms of three forms of infection were observed. To improve the phytosanitary condition of crops, it is necessary to optimize the saturation of crop rotation with sunflower and other technical crops, which are also one of the host plants of the pathogen, and to follow of all elements of the protection system.

Fungal biodiversity on maize kernels in an insecticide evaluation trial

The European corn borer (ECB) Ostrinia nubilalis and Fusarium ear rot Fusarium spp. pose a continuous threat to maize production worldwide. There are several reports indicating that ECB damage to maize ears promotes Fusarium ear rot infection. The aim of this study was to monitor the influence of different insecticide treatments (a.i. chlorantraniliprole, indoxacarb, and chlorantraniliprole+lambda-cyhalothrin) on the ECB and fungal diversity on maize kernels in the field in a four-year trial (2013-2016). A total of 16 different fungal genera were isolated from maize kernels, and Fusarium species were confirmed to be the dominant pathogens, present in all treatments, throughout the four years of experiments. The incidence of Aspergillus spp. and Penicillium spp. was established to be low. Apart from Fusarium species, the most frequent genera were: Aspergillus spp., Mortierella spp., Mucor spp., Penicillium spp., Acremonium spp. and Rhizopus spp. Treatments with chlorantraniliprole and chlorantraniliprole+lambda-cyhalothrin showed higher efficacy, though not statistically significant, compared to indoxacarb, in reducing the number of ECB larvae and damage they cause. However, no direct effect on the number of isolated fungal genera has been observed in any of the three insecticide treatments.

Organic matter input influences incidence of root rot caused by Rhizoctonia solani AG8 and microorganisms associated with plant root disease suppression in three Australian agricultural soils

Soil-borne plant root disease caused by Rhizoctonia solani AG8 is prevalent in cereal farming systems worldwide, particularly in semiarid agricultural regions. A controlled environment study was undertaken using three Australian soils to test the hypothesis that OM input from crop roots and residues decreases infection by Rhizoctonia root rot via biologically mediated disease suppression. The specific aim was to determine the relative effect of two different OM inputs (wheat stubble or roots) on (a) abundance (DNA) of the pathogen R. solani AG8 and soil organisms putatively associated with disease suppression, and (b) incidence of Rhizoctonia root rot infection of wheat seedlings (% root infected). An increase in microbial biomass carbon (C) following OM amendment indicated a potential for enhanced general biological disease suppression in all soils. OM inputs also increased the population size (DNA) of certain bacteria and fungi putatively associated with specific suppression for Rhizoctonia root rot, suggesting a C resource-mediated change in microbial functions related to disease suppression. There were no significant changes to measured pathogens with stubble addition. However, OM inputs via root residues and rhizodeposits from living roots increased the populations of R. solani AG8 and Gaeumannomyces graminis var. tritici so that in subsequently planted wheat there was greater incidence of root disease infection and reduced plant shoot and root DM compared with that following OM input as stubble. Differences between soils in terms of plant and soil organism responses to each OM input suggest that abiotic factors modify the development of biological disease suppression and the expression of the disease.

Impact of Organic Manure Combinations on Performance and Rot Infection of Stressed-Jerusalem Artichoke Plants

Impact of Organic Manure Combinations on Performance and Rot Infection of Stressed-Jerusalem Artichoke Plants

Roots, the hidden tree

In order to adapt the forces a forestry machine to the ground conditions and avoid rutting, ground and tree damages, we must know more about the strength of roots, since they are important factors for the strength of the forest floor. Also tree root bark strength is important to avoid root damages which may cause rot infections in the tree.

ATR-FTIR spectroscopy non-destructively detects damage-induced sour rot infection in whole tomato fruit

Main conclusionATR-FTIR spectroscopy with subsequent multivariate analysis non-destructively identifies plant–pathogen interactions during disease progression, both directly and indirectly, through alterations in the spectral fingerprint.Plant–environment interactions are essential to understanding crop biology, optimizing crop use, and minimizing loss to ensure food security. Damage-induced pathogen infection of delicate fruit crops such as tomato (Solanum lycopersicum) are therefore important processes related to crop biology and modern horticulture. Fruit epidermis as a first barrier at the plant–environment interface, is specifically involved in environmental interactions and often shows substantial structural and functional changes in response to unfavourable conditions. Methods available to investigate such systems in their native form, however, are limited by often required and destructive sample preparation, or scarce amounts of molecular level information. To explore biochemical changes and evaluate diagnostic potential for damage-induced pathogen infection of cherry tomato (cv. Piccolo) both directly and indirectly, mid-infrared (MIR) spectroscopy was applied in combination with exploratory multivariate analysis. ATR-FTIR fingerprint spectra (1800–900 cm−1) of healthy, damaged or sour rot-infected tomato fruit were acquired and distinguished using principal component analysis and linear discriminant analysis (PCA–LDA). Main biochemical constituents of healthy tomato fruit epidermis are characterized while multivariate analysis discriminated subtle biochemical changes distinguishing healthy tomato from damaged, early or late sour rot-infected tomato indirectly based solely on changes in the fruit epidermis. Sour rot causing agent Geotrichum candidum was detected directly in vivo and characterized based on spectral features distinct from tomato fruit. Diagnostic potential for indirect pathogen detection based on tomato fruit skin was evaluated using the linear discriminant classifier (PCA–LDC). Exploratory and diagnostic analysis of ATR-FTIR spectra offers biological insights and detection potential for intact plant–pathogen systems as they are found in horticultural industries.

Histology-guided high-resolution AP-SMALDI mass spectrometry imaging of wheat-Fusarium graminearum interaction at the root\u2013shoot junction

BackgroundFungal pathogens like Fusarium graminearum can cause severe yield losses and mycotoxin contamination of food and feed worldwide. We recently showed its ability to systemically colonize wheat via root infection. However, the molecular response of wheat to Fusarium root rot (FRR) infection and systemic spread is still unknown. As a molecular camera, mass spectrometry (MS) imaging combines label-free and multiplex metabolite profiling with histopathology.ResultsAtmospheric-pressure (AP)-SMALDI-MS imaging was combined with optical microscopy to study wheat-F. graminearum interaction at the root–shoot junction, which is a crucial line of defense against a pathogen that can invade all distal plant parts. To scope the functional, temporal and local aspects of FRR disease spread, metabolic changes were simultaneous visualized in diseased and healthy stem bases of the resistant cultivar Florence-Aurore at 10, 14 and 21 days after root inoculation. Histological information was used to identify disease relevant tissues and to assist the interpretation of molecular images. Detected mycotoxin compounds secreted by F. graminearum showed a route of stem infection that was consistent with observations made by microscopy. The outer epidermis and vasculature of leaf sheath were, at different disease stages, identified as prominent sites of pathogen migration and wheat protection. Wheat metabolites mapped to these relatively small tissues indicated cell wall strengthening and antifungal activity as direct defenses as well as conservation in the wheat reactions to F. graminearum diseases that affect different plant organs.ConclusionsAP-SMALDI-MS imaging at high spatial resolution is a versatile technique that can be applied to basic and applied aspects of agricultural research. Combining the technology with optical microscopy was found to be a powerful tool to gain in-depth information on almost unknown crop disease. Moreover, the approach allowed studying metabolism at the host–pathogen interface. The results provide important hints to an understanding of the complex spatio-temporal organization of plant resistance. Defense-on-demand responses to pathogen ingress were found, which provide opportunities for future research towards an improved resistance that does not negatively impact yield development in the field by saving plant resources and, moreover, may control different Fusarium diseases.

Hyperspectral band selection using genetic algorithm and support vector machines for early identification of charcoal rot disease in soybean stems

BackgroundCharcoal rot is a fungal disease that thrives in warm dry conditions and affects the yield of soybeans and other important agronomic crops worldwide. There is a need for robust, automatic and consistent early detection and quantification of disease symptoms which are important in breeding programs for the development of improved cultivars and in crop production for the implementation of disease control measures for yield protection. Current methods of plant disease phenotyping are predominantly visual and hence are slow and prone to human error and variation. There has been increasing interest in hyperspectral imaging applications for early detection of disease symptoms. However, the high dimensionality of hyperspectral data makes it very important to have an efficient analysis pipeline in place for the identification of disease so that effective crop management decisions can be made. The focus of this work is to determine the minimal number of most effective hyperspectral wavebands that can distinguish between healthy and diseased soybean stem specimens early on in the growing season for proper management of the disease. 111 hyperspectral data cubes representing healthy and infected stems were captured at 3, 6, 9, 12, and 15 days after inoculation. We utilized inoculated and control specimens from 4 different genotypes. Each hyperspectral image was captured at 240 different wavelengths in the range of 383–1032 nm. We formulated the identification of best waveband combination from 240 wavebands as an optimization problem. We used a combination of genetic algorithm as an optimizer and support vector machines as a classifier for the identification of maximally-effective waveband combination.ResultsA binary classification between healthy and infected soybean stem samples using the selected six waveband combination (475.56, 548.91, 652.14, 516.31, 720.05, 915.64 nm) obtained a classification accuracy of 97% for the infected class. Furthermore, we achieved a classification accuracy of 90.91% for test samples from 3 days after inoculation using the selected six waveband combination.ConclusionsThe results demonstrated that these carefully-chosen wavebands are more informative than RGB images alone and enable early identification of charcoal rot infection in soybean. The selected wavebands could be used in a multispectral camera for remote identification of charcoal rot infection in soybean.

Fusarium and Pythium species infecting roots of hydroponically grown marijuana (Cannabis sativa L.) plants

An increase in the cultivation of Cannabis sativa (cannabis or marijuana) plants in Canada is becoming associated with increased incidence and severity of various diseases, many of which have not been previously reported. In this study, hydroponically grown C. sativa plants were sampled over a 3-year period (2014–2017) to determine the prevalence of root pathogens. Following isolation, pathogenicity studies were conducted to establish the extent of disease symptoms caused by the recovered microbes. Root rot was found to be caused by two Pythium species – Pythium dissotocum Drechsler and P. myriotylum Drechsler. As well, two Fusarium species were recovered from diseased plants – Fusarium oxysporum Schlecht. emend. Snyder & Hansen and F. solani (Mart.) Sacc. Upon inoculation onto healthy plants, all isolates of Pythium spp. caused browning and a reduction in root mass, accompanied by stunting. Inoculation of plants with F. oxysporum caused browning of roots and crown rot infection, accompanied by pith and vascular discolouration, and in some cases wilting of plants, while root and crown infection was observed with F. solani. Phylogenetic analysis of internal transcribed spacer (ITS) and elongation factor 1α (EF-1α) sequences revealed that the Fusarium species affecting cannabis plants shared 99–100% sequence homology with isolates causing stem rot and wilt in other hosts, including cumin and tomato, suggesting they were not uniquely adapted to cannabis. The potential for spread of F. oxysporum through the hydroponic system was confirmed by its detection in the recirculating nutrient solution. Furthermore, rooted cuttings obtained from commercial propagators were found to harbour Fusarium root infection that resulted in subsequent stunting, yellowing and occasional death of plants. This demonstrates the potential for long-distance spread of the pathogen. The two Pythium species recovered from cannabis plants have an extremely broad host range and are not unique to this host. An additional species, P. aphanidermatum (Edson) Fitzp., was recovered from diseased plants grown under greenhouse conditions in 2018. The management of these root pathogens on C. sativa will require the evaluation and implementation of sanitization methods, biological control agents, and chemical products adapted from greenhouse vegetable production practices. The use of pathogen-free propagation materials and identification of potential sources of disease resistance should also become a priority.

Role of benzoic and salicylic acids in the immunization of oil palm seedlings-challenged by Ganoderma boninense

Basal stem rot (BSR) infection of oil palm, caused by Ganoderma boninense, is one of the key constraining components in palm oil production causing considerable economic losses around the world. Although it was reported a century before, till date no effective controller has been identified, the alteration of lignin content in oil palm can control the BSR is one of the hypothesis. Since the degradation of lignin is the rate limiting step in the infection process of BSR disease. Two naturally occurring phenolic compounds such as benzoic acid and salicylic acid are known to play a key role in the plant defence as well as in the lignin synthesis. The goal of this research is to evaluate the effect of these two naturally occurring phenolic compounds against G. boninense. In this study, oil palm seedlings were immunized with various concentrations (1–15 mM) of benzoic acid and salicylic acid, prior to G. boninense inoculation. After challenging the oil palm seedlings with G. boninense, BSR progression along with the changes in defence enzymes (Phenylalanine ammonia lyase, Peroxidase, and Polyphenol oxidase), and the total lignin contents were examined and evaluated. The exogenous application of the phenolic compounds have not only suppressed the BSR infection but also promoted the plant growth significantly (P ≤ 0.01). The disease suppression was due to the increased production of defence enzymes particularly polyphenol oxidase which had increased lignin content in the seedlings. An absolute disease reduction was registered in seedlings treated 10 and 15 mM benzoic acid with a significant (P ≤ 0.01) increment in the production of lignin along with the defence enzymes. Whereas the salicylic acid exhibited an ambivalent behavior, at 1 mM salicylic acid induced the disease by 60% however as the concentration had increased to 5 mM suppression in the BSR was observed. The efficiency of phenolic compounds as an agent of disease reduction is found to be concentration dependent. The outcome of this study has found that benzoic acid at 15 mM concentration is a superior controller for the BSR disease suppression in oil palm. This study would pave the way towards a new management strategy to replace the chemical controls by naturally occurring phenolic compounds to control BSR effectively in oil palm ranches.

The use of gas phase detection and monitoring of potato soft rot infection in store

Soft rot caused mainly by the bacterium Pectobacterium carotovorum is a major cause of potato post-harvest storage losses. This work reports on pre-symptomatic detection and monitoring of soft rot under laboratory and commercial research store conditions by means of an array of gas sensors (specifically metal oxide, electrochemical, photoionization and non-dispersive infrared).Two different types of time course experiments were completed. The first set of experiments, under laboratory conditions, evaluated a prototype instrument with various representative sample types for different stages of disease progression in potato tubers. This allowed for optimisation of all parameters for subsequent testing in a potato store. The second set of experiments evaluated an optimised sensor array for soft rot monitoring under realistic potato store conditions. Results showed that a number of gas sensors could detect and monitor early soft rot development with considerable accuracy.

Modelling greenhouse climate factors to constrain internal fruit rot (Fusarium spp.) in bell pepper

Internal fruit rot in bell pepper is an important fungal disease which results in mycelium growth and/or necrosis on the ovarium and fruit flesh. It is mainly caused by members of the Fusarium lactis species complex and emerged as a major threat for bell pepper production worldwide. Infection already starts during anthesis, but the symptoms are only visible later on in the production chain. An accurate prediction of the disease incidence in the greenhouse based on environmental parameters is an important step towards a sustainable disease control. Based on a large dataset (2011–2016), a binomial, logistic regression model was developed. This model enables an accurate prediction of internal fruit rot occurrence based on simple and robust input parameters such as temperature and relative humidity during anthesis. Spore density was included as a simplified, practical parameter describing the presence or absence of internal fruit rot 1 week earlier. The obtained model was validated with an independent dataset of five different commercial bell pepper greenhouses. The chance of internal fruit rot infection increased with temperature and relative humidity. Once a greenhouse is infected, only lower temperatures can reduce future risks. However, the chance of the disease to occur remains very high. This prediction model offers a strong instrument for growers to optimize greenhouse climate conditions to restrain internal fruit rot incidence. In addition, the model can be used to apply accurate biological or chemical treatments to achieve a more sustainable greenhouse control. A guideline table for climate adjustment is presented.

Filamentous fungi associated with natural infection of noble rot on withered grapes

The effects of noble rot infection of grapes on the characteristics of different types of wine, including Italian passito wine, are well known. Nevertheless, there is still little information on filamentous fungi associated with noble-rotten grapes. In this study, withered Garganega grapes for passito wine production, naturally infected by noble rot, were analyzed and compared to sound grapes. Skin morphology and fungal population on berry surfaces were analyzed. Scanning electron microscopy analysis revealed microcracks, germination conidia and branched hyphae on noble-rotten berries. Penicillium, Aureobasidium and Cladosporium were the most frequent genera present. Analysis of single berries displayed higher heterogeneity of epiphytic fungi in those infected by noble-rot than in sound berries. Penicillium adametzoides, Cladosporium cladospoirioides and Coniochaeta polymorpha were recovered. These, to the best of our knowledge, had never been previously isolated from withered grapes and, for C. polymorpha, from grapevine. This study provided novel data on noble rot mycobiota and suggests that fungi that co-habit with B. cinerea could have an important role on grape and wine quality.

Pomerelle Russet: an Early Maturing Potato Variety with High Yields of U.S. No. 1 Tubers Suitable for Fresh Market and mid-Storage Processing and Tolerance to Potato Mop-top Virus

Pomerelle Russet is an early maturing fresh potato variety, which produces moderately high early-season (95–110 days after planting) yields of long tubers with brown-russet skin. It is notable for its very attractive, smooth tubers and resistances to internal and external defects with a high percentage of U.S. No. 1 tubers. Fresh merit ratings for Pomerelle Russet in trials conducted in Idaho, Oregon and Washington were consistently higher than Russet Burbank and Russet Norkotah. Early harvest yields for Pomerelle Russet are generally comparable to Russet Norkotah with a higher percentage of U.S. No. 1 tubers. Compared to Russet Burbank and Russet Norkotah, Pomerelle Russet has greater resistance to Potato mop-top virus, soft rot, corky ringspot and tuber infections from late blight. It also has higher protein and vitamin C concentrations than Ranger Russet, Russet Burbank and Russet Norkotah, indicating that it can provide an enhanced level of dietary protein and vitamin C relative to these standard potato varieties. Pomerelle Russet has moderate specific gravity and good resistance to sugar ends. It also has moderately long dormancy, about 30 days shorter than Russet Burbank. Average post-harvest processing ratings for Pomerelle Russet were similar to Ranger Russet and greater than Russet Burbank. Pomerelle Russet also has maintained acceptable fry color for about 180–200 days in storage at 8.9 °C, indicating potential for processing out of mid-term storage, with improved fry color uniformity relative to industry standards. However, its primary use appears to be as a high quality, early fresh variety.