Postharvest Rot of Pomegranate Fruit in Southern Italy: Characterization of the Main Pathogens

Concurrent application of bacterial-mediated and mycosynthesized ZnO nanofungicides to maintain high ascorbic acid and delay postharvest decay of apricot

Quality of apricot fruit is affected by different biotic stresses during growth, harvesting and storage. Due to fungal attack, huge losses of its quality and quantity are observed. The present research was designed for the diagnoses and management of postharvest rot disease of apricot. Infected apricot fruit were collected, and the causative agent was identified as A. tubingensis. To control this disease, both bacterial-mediated nanoparticles (b-ZnO NPs) and mycosynthesized nanoparticles (f-ZnO NPs) were used. Herein, biomass filtrates of one selected fungus (Trichoderma harzianum) and one bacterium (Bacillus safensis) were used to reduce zinc acetate into ZnO NPs. The physiochemical and morphological characters of both types of NPs were determined. UV-vis spectroscopy displayed absorption peaks of f-ZnO NPs and b-ZnO NPs at 310-380 nm, respectively, indicating successful reduction of Zinc acetate by the metabolites of both fungus and bacteria. Fourier transform infrared (FTIR) determined the presence of organic compounds like amines, aromatics, alkenes and alkyl halides, on both types of NPs, while X-ray diffraction (XRD) confirmed nano-size of f-ZnO NPs (30 nm) and b-ZnO NPs (35 nm). Scanning electron microscopy showed flower-crystalline shape for b-ZnO NPs and spherical-crystalline shape for f-ZnO NPs. Both NPs showed variable antifungal activities at four different concentrations (0.25, 0.50, 0.75 and 1.00 mg/ml). Diseases control and postharvest changes in apricot fruit were analyzed for 15 days. Among all treatments, 0.50 mg/ml concentration of f-ZnO NPs and 0.75 mg/ml concentration of b-ZnO NPs exhibited the strongest antifungal activity. Comparatively, f-ZnO NPs performed slightly better than b-ZnO NPs. Application of both NPs reduced fruit decay and weight, maintained higher ascorbic acid contents, sustained titratable acidity, and preserved firmness of diseased fruit. Our results suggest that microbial synthesized ZnO NPs can efficiently control fruit rot, extend shelf life, and preserve the quality of apricot.

Are Basic Substances a Key to Sustainable Pest and Disease Management in Agriculture? An Open Field Perspective

Pathogens and pests constantly challenge food security and safety worldwide. The use of plant protection products to manage them raises concerns related to human health, the environment, and economic costs. Basic substances are active, non-toxic compounds that are not predominantly used as plant protection products but hold potential in crop protection. Basic substances' attention is rising due to their safety and cost-effectiveness. However, data on their protection levels in crop protection strategies are lacking. In this review, we critically analyzed the literature concerning the field application of known and potential basic substances for managing diseases and pests, investigating their efficacy and potential integration into plant protection programs. Case studies related to grapevine, potato, and fruit protection from pre- and post-harvest diseases and pests were considered. In specific cases, basic substances and chitosan in particular, could complement or even substitute plant protection products, either chemicals or biologicals, but their efficacy varied greatly according to various factors, including the origin of the substance, the crop, the pathogen or pest, and the timing and method of application. Therefore, a careful evaluation of the field application is needed to promote the successful use of basic substances in sustainable pest management strategies in specific contexts.

Postharvest Diseases of Pomegranate: Alternative Control Means and a Spiderweb Effect

The pomegranate is a fruit known since ancient times for its beneficial properties. It has recently aroused great interest in the industry and among consumers, leading to a significant increase in demand. Consequently, its cultivation has been boosted all over the world. The pomegranate crop suffers considerable yield losses, especially at the postharvest stage, because it is a "minor crop" with few permitted control means. To control latent (Alternaria spp., Botrytis spp., Coniella spp., Colletotrichum spp., and Cytospora spp.) and wound (Aspergillus spp., Penicillium spp., and Talaromyces spp.) fungal pathogens, different alternative compounds, previously evaluated in vitro, were tested in the field on pomegranate cv. Wonderful. A chitosan solution, a plant protein hydrolysate, and a red seaweed extract were compared with a chemical control treatment, all as preharvest (field application) and postharvest treatments and their combinations. At the end of the storage period, the incidence of stamen infections and external and internal rots, and the severity of internal decay were evaluated. Obtained data revealed that pre- and postharvest application of all substances reduced the epiphytic population on stamens. Preharvest applications of seaweed extract and plant hydrolysate were the most effective treatments to reduce the severity of internal pomegranate decays. Furthermore, the influence of spider (Cheiracanthium mildei) cocoons on the fruit calyx as a possible barrier against postharvest fungal pathogens was assessed in a 'Mollar de Elche' pomegranate organic orchard. Compared to no-cocoon fruit (control), the incidence of infected stamens and internal molds in those with spiderwebs was reduced by about 30%, and the mean severity of internal rots was halved. Spiderwebs analyzed via Scanning Electron Microscopy (SEM) disclosed a layered, unordered structure that did not allow for the passage of fungal spores due to its mean mesh size (1 to 20 µm ca). The aims of this research were (i) to evaluate alternative compounds useful to control postharvest pomegranate decays and (ii) to evaluate the effectiveness of spiders in reducing postharvest fungal infections by analyzing related mechanisms of action. Alternative control means proposed in the present work and calyx spider colonization may be helpful to reduce postharvest pomegranate diseases, yield losses, and waste production in an integrated control strategy, satisfying organic agriculture and the planned goals of Zero Hunger Challenge launched by the United Nations.

Pest categorisation of Coniella granati

The EFSA Plant Health Panel performed a pest categorisation of Coniella granati, a clearly defined fungus of the Order Diaporthales and the family Schizoparmaceae, described for the first time in 1876 as Phoma granatii and later named as Pilidiella granati. The pathogen mainly affects Punica granatum (pomegranate) and Rosa spp. (rose), causing fruit rot, shoot blight and cankers on crown and branches. The pathogen is present in North America, South America, as well as in Asia, Africa, Oceania and Eastern Europe and has also been reported in the EU (Greece, Hungary, Italy and Spain), where it is widespread in the major pomegranate growing areas. Coniella granati is not included in Commission Implementing Regulation (EU) 2019/2072 and there are no interceptions in the EU. This pest categorisation focused on those hosts for which the pathogen was detected and formally identified in natural conditions. Plants for planting, fresh fruits and as well as soil and other plant growing media are the main pathways for the further entry of the pathogen into the EU. Host availability and climate suitability factors occurring in parts of the EU are favourable for the further establishment of the pathogen. In the area of its present distribution, including Italy and Spain, the pathogen has a direct impact in pomegranate orchards as well as during post-harvest storage. Phytosanitary measures are available to prevent the further introduction and spread of the pathogen into the EU. Coniella granati does not satisfy the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest as it is present in several EU MSs.

Isolation of the Main Pathogens Causing Postharvest Disease in Fresh Angelica sinensis during Different Storage Stages and Impacts of Ozone Treatment on Disease Development and Mycotoxin Production

Angelica sinensis, a Chinese herbal medicine, is susceptible to molds during storage, reducing its quality, and even generating mycotoxins with toxic effects on human health. Fresh A. sinensis was harvested from Min County of Gansu Province in China and kept at room temperature. Naturally occurring symptoms were observed during different storage stages. Molds were isolated and identified from the diseased A. sinensis using morphological and molecular biology methods. The impact of ozone treatment on postharvest disease development and mycotoxin production was investigated. The results indicated that A. sinensis decay began on day 7 of storage and progressed thereafter. Nine mold species were isolated and characterized: day 7, two Mucormycetes; day 14, Clonostachys rosea; day 21, two Penicillium species and Aspergillus versicolor; day 28, Alternaria alternata and Trichoderma atroviride; and day 49, Fusarium solani. Ozone treatment markedly inhibited the development of postharvest disease and the mycotoxin production (such as, patulin, 15-acetyl-deoxynivalenol, and sterigmatocystin) in the rotten tissue of A. sinensis inoculated with the nine isolates.

Isolation of Main Pathogens Causing Postharvest Disease in Fresh Codonopsis pilosula during Different Storage Stages and Ozone Control against Disease and Mycotoxin Accumulation

Codonopsis pilosula is an important Chinese herbal medicine. However, fresh C. pilosula is prone to decay during storage due to microorganism infections, seriously affecting the medicinal value and even causing mycotoxin accumulation. Therefore, it is necessary to study the pathogens present and develop efficient control strategies to mitigate their detrimental effects on the herbs during storage. In this study, fresh C. pilosula was collected from Min County in Gansu Province, China. The natural disease symptoms were observed during different storage stages, and the pathogens causing C. pilosula postharvest decay were isolated from the infected fresh C. pilosula. Morphological and molecular identification were performed, and pathogenicity was tested using Koch's postulates. In addition, the control of ozone was examined against the isolates and mycotoxin accumulation. The results indicated that the naturally occurring symptom increased progressively with the extension of storage time. The mucor rot caused by Mucor was first observed on day 7, followed by root rot caused by Fusarium on day 14. Blue mold disease caused by Penicillum expansum was detected as the most serious postharvest disease on day 28. Pink rot disease caused by Trichothecium roseum was observed on day 56. Moreover, ozone treatment significantly decreased the development of postharvest disease and inhibited the accumulations of patulin, deoxynivalenol, 15-Acetyl-deoxynivalenol, and HT-2 toxin.

Characterization of Alternaria and Colletotrichum Species Associated with Pomegranate (Punica granatum L.) in Maharashtra State of India

Fungal pathogens are a major constraint affecting the quality of pomegranate production around the world. Among them, Alternaria and Colletotrichum species cause leaf spot, fruit spot or heart rot (black rot), and fruit rot (anthracnose) or calyx end rot, respectively. Accurate identification of disease-causing fungal species is essential for developing suitable management practices. Therefore, characterization of Alternaria and Colletotrichum isolates representing different geographical regions, predominantly Maharashtra-the Indian hub of pomegranate production and export-was carried out. Fungal isolates could not be identified based on morphological characteristics alone, hence were subjected to multi-gene phylogeny for their accurate identification. Based on a maximum likelihood phylogenetic tree, Alternaria isolates were identified as within the A. alternata species complex and as A. burnsii, while Colletotrichum isolates showed genetic closeness to various species within the C. gloeosporioides species complex. Thus, the current study reports for the first time that, in India, the fruit rots of pomegranate are caused by multiple species and not a single species of Alternaria and Colletotrichum alone. Since different species have different epidemiology and sensitivity toward the commercially available and routinely applied fungicides, the precise knowledge of the diverse species infecting pomegranate, as provided by the current study, is the first step towards devising better management strategies.

Morphological and Molecular Identification of Fusarium ipomoeae as the Causative Agent of Leaf Spot Disease in Tobacco from China

Tobacco (Nicotiana tabacum L.), which creates jobs for 33 million people and contributes two trillion dollars’ tax annually, is one of the most important economic plants globally. However, tobacco is seriously threatened by numerous diseases during production. Previously, the field survey of tobacco diseases was conducted in the Guizhou and Guangxi provinces, the two main tobacco-producing areas in China. A serious leaf spot disease, with a 22% to 35% incidence, was observed in farming plants. In order to determine the causal agents, we collected the disease samples and isolated the pathogenic fungi. The pathogen was identified as Fusariumipomoeae, based on the morphological characteristics and phylogenetic analysis. Pathogenicity tests showed that F. ipomoeae could induce tobacco leaf spot and blight. To our knowledge, this is the first report worldwide of F. ipomoeae causing leaf spots and stems on tobacco. Our study reveals the serious consequences of F. ipomoeae on tobacco filed production and provides information for future diagnosis and management of the Fusarium disease.