The pre and postharvest disease named ‘aqueous spot’ is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear in the tree, but it is usually detected after harvesting, during the postharvest period. Symptoms include the appearance of skin discolouration and translucency in the shoulder areas. At the most advanced stages, a mycelium of white colour partially or completely covers the fruit. This manuscript provides a detailed description of the microbes involved in this disease, such as bacteria, yeasts, and moulds. Microbes of different cherry cultivars were studied during two consecutive seasons (2019 and 2020). The counts of bacteria and yeast in damaged tissues were higher (7.05 and 6.38 log10 CFU/g for total aerobic mesophilic microbes and yeasts, respectively) than sound tissues (6.08 and 5.19 log10 CFU/g, respectively). The Enterobacterales order dominated the bacteria population. Among yeasts, Yarrowia lipolytica, in 2019, and Metschnikowia pulcherrima and Metschnikowia viticola, in 2020, were consistently isolated from all samples. The presence of moulds was inconsistently detected at the early stage of this disease by plate counts. However, microscopic observations revealed the presence of hyphae in cherry flesh. Different pathogenic moulds were identified, although white mycelium, identified as Botrytis cinerea by molecular methods, was consistently isolated at later stages. Inoculation tests confirmed the involvement of white-mycelium B. cinerea in the development of this new postharvest disease in the Jerte Valley. Its combination with Enterobacterales enhanced the evolution of rotting, whereas the combination with yeasts decreased and delayed the symptoms. This work presents the first report of a consortia of microorganisms implicated in the development of ‘aqueous spot’, an emerging disease in sweet cherry cultivars in the Jerte Valley.

Fresh figs are a highly perishable fruit with a very limited shelf life. Consequently, the development of innovative strategies at both the preharvest and postharvest stages is essential to enhance their quality and extend their shelf life. This study aimed to evaluate the postharvest performance of fresh figs (cv. Calabacita) treated preharvest with oxalic acid (OA) via foliar spraying at 1.2 L per tree at two concentrations (1 and 2 mM), applied either twice or three times. Figs were harvested at commercial maturity and stored for 10 days at 1 °C and 90% relative humidity in darkness, with sampling carried out at 0, 3, 7 and 10 days. At each sampling point, physiological, physicochemical, and bioactive parameters were assessed, and an analysis of variance was performed to determine differences among OA treatments. The findings showed that the effectiveness of OA depended on the number of applications, with two preharvest sprays providing the most favourable outcomes. OA at 2 mM significantly reduced weight loss, respiration rate, and ethylene production compared with controls and increased titratable acidity. Furthermore, all OA treatments enhanced the antioxidant activity of the fruit, improving both enzymatic and non-enzymatic antioxidant activity, as well as total phenolic content. This suggests improved stress tolerance supported by lower cell wall oxidation at the end of cold storage. In conclusion, two preharvest applications of oxalic acid effectively contribute to maintaining fruit quality and extending the storability of fresh figs during cold storage.

This study investigated the seasonal and spatial dynamics of off-flavour compounds—geosmin and 2-methylisoborneol (2-MIB)—in an intensive rainbow trout (Oncorhynchus mykiss) aquaculture system for human consumption in western Spain. Weekly water and fish flesh samples were collected over a 12-month period from three farms supplied by the River Tormes. Physicochemical parameters, determination of geosmin and 2-MIB by SPME-GC-MS, microbial counts, and microbial community composition were assessed alongside volatile compound concentrations. Geosmin and 2-MIB showed marked seasonal variation, with peak levels in water and fish flesh during spring and summer, correlating positively with temperature. Geosmin accumulation in fish was highest in the downstream farm, suggesting cumulative exposure effects. In contrast, 2-MIB was detected only in water and at lower concentrations. Microbial analyses revealed high bacterial and fungal diversity, including cyanobacterial taxa such as Phormidium setchellianum and Pseudoanabaena minima, known producers of geosmin and 2-MIB. These findings highlight the importance of water microbiota and environmental conditions in off-flavour development. Managing cyanobacterial populations and monitoring spatial-temporal variability are essential to mitigate the development of earthy or musty flavours and economic losses in aquaculture systems.

Plums are climacteric fruits with a short postharvest shelf-life, which makes them highly susceptible to spoilage by moulds and pathogens. Biological control using antagonistic yeasts offers a promising approach to extend shelf-life by inhibiting fungal growth. This study evaluated the effects of two yeast strains, Hanseniaspora uvarum L793 and Metschnikowia pulcherrima L672, on the quality of ‘Larry Ann’ Japanese plums during cold storage. Plums were divided into three batches: two treated by immersion in yeast suspensions (10⁸ cells mL⁻¹) and one untreated control. Quality parameters assessed over 12 weeks at 1 °C included weight loss, decay index, microbial counts, yeast colonisation, skin and flesh colour, texture, pH, titratable acidity, total soluble solids, and ripening index, with evaluations every week. M. pulcherrima L672 showed strong colonisation and persistence on the plum surface, significantly reducing skin damage and mould incidence. In contrast, H. uvarum L793 initially colonised well but declined over time, being replaced by native yeasts such as Aureobasidium spp. Both treatments maintained the physicochemical and organoleptic quality of the plums throughout storage. However, M. pulcherrima L672 was more effective in suppressing fungal growth and preserving fruit integrity. These findings suggest that M. pulcherrima L672 is a promising biocontrol agent for prolonging the shelf-life of Japanese plums during cold storage, maintaining their commercial quality for up to three months.

Fresh figs are characterised by high perishability, leading to a limited postharvest shelf life. Consequently, preharvest elicitor application strategies have been explored to enhance their quality and storability. During the 2022 and 2023 seasons, figs (cv. Calabacita) grown under high-density conditions were treated with oxalic acid (OA; 1 and 2 mM), melatonin (MEL; 0.1 and 0.5 mM), and γ-aminobutyric acid (GABA; 10 and 50 mM) through foliar sprays applied two or three times. Fruits were harvested at commercial maturity and analysed immediately after harvest. Physicochemical and bioactive parameters were determined. Analysis of variance was used to assess treatment effects, and t-tests were used to evaluate differences in the number of applications and between seasons. Significant seasonal effects were observed, whereas no cumulative effect from repeated applications was detected. OA at 2 mM increased fruit weight (37.9 g) and size (42.5 mm) and delayed ripening. MEL treatments enhanced sugar accumulation (100.1 g kg⁻¹ and 96 g kg⁻¹ of glucose and fructose, respectively), while GABA treatments were associated with a more advanced maturity stage. Notably, OA (2 mM), MEL (0.5 mM), and GABA (50 mM) significantly increased enzymatic antioxidant activity by an average of 24% and non-enzymatic antioxidant capacity by around 17% in general terms. These results indicate that preharvest elicitor application is a promising and eco-friendly approach to improve the nutritional value and overall quality of fresh figs.

Fusarium species represent a significant threat to pasture health, necessitating the development of sustainable solutions. This study explores the potential of regionally adapted Trichoderma isolates for controlling Fusarium avenaceum and promoting plant growth in the grasslands of the Iberian Peninsula. To this end, seven Trichoderma isolates (belonging to T. koningiopsis, T. koningii and T. gamsii) were obtained from soils of Extremadura and then evaluated as potential biocontrol agents against Fusarium avenaceum. For the purposes of this evaluation, water was used as a negative control, while a commercial Trichoderma product served as a positive control. An initial in vitro evaluation revealed that six Trichoderma isolates significantly inhibited F. avenaceum in a dual culture assay, reducing pathogen growth by 18 to 49%. Additionally, two of the isolates showed antifungal potential during the evaluation of their culture filtrates. Subsequently, two greenhouse assays were conducted to assess the effects of Trichoderma isolates and the pathogen on the development of Lolium perenne. One focused on seed germination and the other on established plants. The greenhouse experiments indicated that T08 (T. koningiopsis), T14 (T. koningii), and T19 (T. gamsii) significantly improved seed germination and plant growth, even outperforming the positive control on total dry matter in pathogen-infected plants during the postemergence test. Our study highlights the potential of Trichoderma isolates, particularly T08, T14, and T19, to boost plant growth and control Fusarium avenaceum in Lolium perenne. It emphasizes the importance of in planta testing and reveals the varying effects of the isolates throughout the plant cycle.