Potencial de extractos bioactivos del hueso y la piel de aguacate para el control de la podredumbre ácida en poscosecha de cítricos

El procesado del aguacate genera una gran cantidad de subproductos que pueden presentar importantes desafíos medioambientales. Estos subproductos agroindustriales, en particular el hueso de aguacate (AVS) y la piel (APE), contienen abundantes compuestos bioactivos, muchos con propiedades antifúngicas, que podrían representar una alternativa a los fungicidas químicos de síntesis para el control de enfermedades de poscosecha, alineándose con la bioeconomía circular y el Pacto Verde de la UE. Se utilizaron extracciones asistidas por ultrasonido (UAE) y microondas (MAE) para obtener extractos de AVS y APE. Se determinaron el contenido total de fenoles (TPC) y la capacidad antioxidante total (TAC) de los extractos. La eficacia de los extractos en la inhibición de Geotrichum citri-aurantii, el agente causal de la podredumbre ácida de los cítricos se evaluó mediante ensayos in vitro con microplacas. Los extractos seleccionados se probaron posteriormente en ensayos primarios in vivo con mandarinas ‘Tango’, las cuales fueron inoculadas con el patógeno en heridas de la piel y tratadas 2 h después depositando una gota del extracto en el punto de inoculación. La incidencia (% de heridas infectadas) y la severidad (diámetro de la lesión) de la podredumbre ácida se midieron después de 7 días de incubación a 20 ºC. Los extractos de AVS y APE presentaron niveles similares de TPC y TAC, independientemente del método de extracción. En los experimentos in vitro, AVS-UAE y AVS-MAE inhibieron completamente G. citri-aurantii, mientras que APE-UAE y APE-MAE no fueron efectivos, por lo que en los ensayos in vivo, solo se evaluaron los extractos de AVS. En estos ensayos, AVS-UAE resultó ser el más eficaz para controlar la podredumbre ácida en mandarinas, reduciendo la incidencia y la severidad de la enfermedad en un 35 y 45%, respectivamente, respecto al control tratado con agua. Estos resultados muestran que los subproductos del aguacate son ricos en compuestos fenólicos, siendo los extractos de AVS los que presentaron actividad antifúngica in vitro contra G. citri-aurantii. En cítricos, el extracto AVS-UAE surge como una alternativa prometedora y no contaminante para reducir la podredumbre ácida

Artificial Neural Networks in Agriculture, the core of artificial intelligence: What, When, and Why

Artificial Neural Networks (ANNs) based models have emerged as a powerful tool for solving complex nonlinear problems in agriculture. These models simulate the human nervous system’s structure, allowing them to learn hierarchical features from the data and solve nonlinear problems efficiently. Despite requiring a large amount of training data, ANNs with shallow architectures demonstrate superior performance in extracting relevant features and establishing accurate models, instilling confidence in their effectiveness compared to conventional machine learning methods. The versatility of ANNs enables their application in various agricultural domains, including precision agriculture, species classification, phenotyping, and food quality and safety assessment. ANNs combined with image analysis have proven valuable in disease detection, plant phenotyping, and fruit quality evaluation. The use of deep learning in agriculture has experienced exponential growth, as evident from the increasing number of publications in recent years. This article overviews recent advancements in applying ANNs in agriculture. It delves into the fundamental principles behind various types of agricultural data and ANN models, discussing their benefits and challenges. The article offers valuable insights into the proper use and functioning of each neural network, data processing for improved model outcomes, and the diverse applications of ANNs in the agricultural sector. It aims to equip readers with practical information on data utilisation, model selection based on data type, functionality, and current research application

Extractos de piel de almendra como compuestos antifúngicos contra enfermedades de poscosecha en nectarinas

La industria de procesado de almendras genera una gran cantidad de subproductos con potencial de aprovechamiento como compuestos de valor añadido, contribuyendo a la economía circular. En este sentido, la piel de almendra (AMS) es conocida por sus propiedades antioxidantes debido a la presencia de polifenoles, los cuales también pueden ejercer cierta actividad antifúngica. En este trabajo, se obtuvieron extractos de AMS utilizando extracción asistidas por microondas (MAE) y se determinaron su contenido total de fenoles (TPC) y su capacidad antioxidante total (TAC). La eficacia del extracto en la inhibición de Botrytis cinerea (BC), Rhizopus stolonifer (RS), Penicillium expansum (PE) y Monilinia fructicola (MF), agentes causales de las podredumbres gris, blanda, azul y marrón, respectivamente, se evaluó in vitro mediante ensayos con microplacas. Los extractos seleccionados se probaron posteriormente en ensayos primarios in vivo con nectarinas ‘Carmina 22’, las cuales fueron inoculadas con los patógenos en heridas de la piel y tratadas 2 h después depositando una gota del extracto en el punto de inoculación. A los 7 días de incubación a 20 °C, se midieron la incidencia (% de heridas infectadas) y la severidad (diámetro de la lesión) de las enfermedades. Los niveles de TPC y TAC del extracto fueron 2,7 GAE/g de peso seco y 16,7 g AAE/L, respectivamente. En los ensayos in vitro, el extracto mostró una alta actividad antifúngica frente a BC, RS y MF, alcanzando porcentajes de inhibición del 90,3%, 99,9% y 98,4%, respectivamente, mientras que fue más moderada en el caso de PE, con un 46,1%. In vivo, AMS-MAE no fue efectivo reduciendo la incidencia y la severidad de las podredumbres marrón y azul en nectarinas. Sin embargo, redujo las de la podredumbre gris en un 42 y 62%, respectivamente, y las de la podredumbre blanda en un 70%, comparado con los frutos control tratados con agua. Estos resultados sugieren que el extracto AMS-MAE es una opción prometedora y respetuosa con el medio ambiente para reducir las podredumbres gris y blanda en nectarinas, ofreciendo una alternativa sostenible a los fungicidas químicos utilizados actualmente para el control de enfermedades fúngicas de poscosecha en fruta de hueso

Global strategies to manage huanglongbing (HLB) and its vectors: insights and implications for the Mediterranean region

Huanglongbing (HLB), also known as citrus greening disease, poses a severe threat to the global citrus industry. This disease is caused by three species of bacteria, ‘Candidatus Liberibacter asiaticus’, ‘C. L. africanus’, and ‘C. L. americanus’. The primary pathogen vectors are the Asian citrus psyllid (Diaphorina citri Kuwayama, Hemiptera: Psyllidae) and the African citrus psyllid (Trioza erytreae Del Guercio, Hemiptera: Triozidae). The disease is incurable, and its management relies on reducing vector densities and the adverse effects of bacterial infections on host trees. Managing psyllid vectors, especially D. citri, has proven exceptionally challenging due to its rapid spread and subsequent difficulty in containing and suppressing newly detected populations. This article reviews strategies developed to manage HLB and its vectors in different regions of the world with a focus on the challenges likely to be faced by the Mediterranean region. Diaphorina citri has recently invaded the Mediterranean region and T. erytreae has been encroaching via the northern Iberian Peninsula for several years. Currently, HLB has not been detected in this important citrus production area. Therefore, this area must implement preventive measures and proactively prepare for potential invasions by D. citri, T. erytreae, and HLB-causing pathogens by developing and adopting comprehensive management strategies in advance of anticipated invasion events

Moisture-dependent pupation of the invasive thrips Chaetanaphothrips orchidii: implications for its management

BACKGROUND: Chaetanaphothrips orchidii is an invasive thrips of tropical origin that was detected in 2016 in Spanish citrus, where it can damage up to 70% of the fruit. Pupation site and emergence rates are key biological traits for thrips management that are unknown for C. orchidii. Here, we determined the pupation site and period of C. orchidii in citrus and evaluated the effect of soil moisture on adult emergence. RESULTS: A two-year field study showed that C. orchidii pupated in the soil from May to December in commercial citrus orchards. Chaetanaphothrips orchidii emergence was very low compared to other harmful thrips species in citrus. Using D/E traps, we demonstrated that the thrips emerged mainly from wet areas near drip irrigation emitters during the summer, and its emergence was strongly related to the soil water content. A laboratory experiment confirmed that C. orchidii did not emerge at RH below 70%, and its emergence peaked at 97% RH. CONCLUSIONS: Our results have important implications for the sustainable management of C. orchidii because soil moisture is very low in Mediterranean citrus during summer, except in areas near drip irrigation emitters. Therefore, these and other potential high-humidity areas should be considered crucial targets to manage this pest in citrus during summer, reducing cost and labor

Effects of environmental conditions and ripeness of the fruit at harvest on the physicochemical quality and internal skin browning of cold-stored ‘Mollar de Elche’ pomegranate

Pomegranate is a cold-sensitive fruit, prone to develop chilling injury (CI) which manifests as external pitting and internal browning. In the case of ‘Mollar de Elche’ pomegranates, storage at 5 °C and >90% relative humidity (RH) is recommended to minimize CI, weight loss, and fungal diseases. However, in recent seasons, increased internal skin browning has been observed, in the absence of typical external CI symptoms. Furthermore, this disorder becomes apparent after a few weeks of storage under optimal conditions. The objective of this work was to study the effects of environmental conditions at harvest (early in the morning (E) with mild temperatures and late in the morning (L) with maximum solar radiation) and harvest date (at the beginning (H1) and the end (H2) of the growing season 2022) on the physicochemical quality and internal tissue browning of ‘Mollar de Elche’ pomegranates stored for 8 and 12 weeks at 6 ºC and 90-95% RH, followed by 7 days at 20 ºC and 85% RH. Differences in solar radiation, ambient temperature and RH at harvest time resulted in fruit temperatures of 15.7±1.8 and 28.1±0.4 ºC for E and L, respectively. No significant differences in internal browning were observed between E and L harvest time, whereas H2 fruit were less susceptible than H1 fruit. Furthermore, fruit with higher internal browning incidence showed higher respiration, weight loss, and electrolyte leakage, indicating damage of the cell membrane. Fruit firmness was greater in H1 than H2 at harvest and after 8 weeks of cold storage plus shelf life, but no differences were observed between treatments at the end of storage. Overall, late-harvest fruit was less susceptible to internal browning. Future work should explore the origin of this physiological disorder and feasible postharvest management to minimize it

Orchard systems offer low-hanging fruit for low-carbon, biodiversity-friendly farming

As core constituents of healthy diets, fruits are often cultivated in temporally stable and structurally complex ecosystems that harbor high levels of biodiversity. However, high-intensity orchard management can lessen the human and environmental health benefits of fruticulture. In the present article, we argue that increased emphasis on biological control could contribute to preventative manage- ment of fruit pests, weeds, and diseases, resulting in pesticide phasedown. Carefully calibrated orchard management can increase the provision of ecosystem services by above- and belowground biota, improve soil health, and store atmospheric carbon. When tactically integrated with agroecological measures, behavior-modifying chemicals, or digital tools, biological control helps to conserve pollinator or soil fauna, protect vertebrate communities, and improve vegetation restoration outcomes. Its implementation can, however, give rise to scientific and social challenges that will need to be explored. By resolving the adoption hurdles for biological control at scale, human society could enjoy the myriad benefits of nature-friendly fruit productio

Response of Amblyseius swirskii to deltamethrin

BACKGROUND The rising demand for environmentally friendly pest control highlights the importance of understanding the interaction between natural enemies and pesticides. Amblyseius swirskii, a predatory mite extensively used in biocontrol, plays a crucial role in managing pest populations in agricultural systems. Integrating this mite with selective pesticide use within integrated pest management (IPM) would significantly advance pest control and may reduce pesticide residues in the environment and agricultural produce. This study characterized the susceptibility of two Amblyseius swirskii colonies to deltamethrin, a widely used pesticide, to assess their potential integration into IPM strategies. RESULTS Both colonies exhibited significant tolerance to deltamethrin at concentrations higher than the maximum recommended field rate. Our analysis identified mutations in the target site in both populations. The commercial population also showed a contribution of cytochromes P450 to the resistant phenotype. Despite these results, semi-field trials revealed a significant reduction in mite counts post-treatment with deltamethrin; various experiments were conducted to understand this discrepancy. CONCLUSION This study underscores the need for comprehensive evaluations of pesticide impacts on biological control agents to optimize IPM strategies. Understanding pesticide resistance and field performance dynamics is crucial for developing sustainable pest management practices that ensure environmental resilience and agricultural productivity

Antifungal edible coatings to reduce postharvest decay and preserve the quality of ‘Mollar de Elche’ pomegranates

Pomegranate exhibits important postharvest quality losses that limit its storage potential, caused mainly by weight loss, chilling injury, and fungal diseases. In this work, the effect of antifungal edible coatings (AECs) formulated with different biopolymers (citrus pectin (PEC), λ-carrageenan (CARG), and their combination PEC-CARG), beeswax (BW) as hydrophobic component, and 0.5% essential oils [EOs, cinnamon (CN) or lemongrass (LG)] as antifungal ingredients were evaluated to control weight loss and natural fungal decay of ‘Mollar de Elche’ pomegranates during storage at ambient temperatures (20°C). Results showed that PEC-based AECs were the most effective in reducing pomegranate decay caused by latent infections by Botrytis cinerea and wound infections by Penicillium spp. During 8 weeks of storage, with no significant differences between coatings formulated with CN or LG EOs. Furthermore, PEC-based coatings also reduced weight loss without causing visible phytotoxicity, while CARG-based coatings were slightly detrimental to the fruit rind. Afterwards, selected AECs were assayed to control natural decay and preserve fruit quality of pomegranates stored at 5°C for 12 weeks plus 1 week of shelf life at 20°C. PEC-based coatings were confirmed as an effective means to reduce weight loss and prevent fruit shriveling of cold-stored pomegranates without negatively affecting the fruit's physicochemical and sensory quality. However, no significant differences in latent and wound external decay were found between control and coated fruits after cold storage and shelf life. In conclusion, PEC-based coatings containing CN or LG EOs at 0.5% could be a promising treatment to extend the postharvest life of ‘Mollar de Elche’ pomegranates, although further studies are required to improve their antifungal effect during cold storage

Chitosan-Based Semen Extenders: An Approach to Antibiotic-Free Artificial Insemination in Rabbit

The use of antibiotics in livestock contributes to antimicrobial resistance, highlighting the need for alternative solutions. Among these, chelating agents, like ethylenediaminetetraacetic acid (EDTA) and Chitosan, have shown potential in reducing bacterial contamination in seminal doses used in artificial insemination (AI), while preserving sperm quality. The objective of this study was to evaluate the potential use of EDTA and Chitosan as alternatives to antibiotics for the liquid storage of rabbit seminal AI doses. Methods: EDTA (20 mM) and Chitosan (0.05%) were tested both individually and in combination, by adding them to the semen extender, and their effects were compared with extenders containing antibiotics or none. The extenders were evaluated for microbial resistance and their ability to maintain sperm quality in vitro during refrigeration at 16 ± 1 ◦C for 72 h. To assess antimicrobial efficacy, Enterococcus faecalis was used. Seminal doses stored for 24 h were used for insemination under commercial conditions, and fertility rate and total kits born were evaluated. Results: Adding 0.05% Chitosan to the extender resulted in sperm parameters and bacterial load comparable to those achieved with antibiotics during refrigerated storage, yielding similar fertility rate and total kits born outcomes 24 h post-storage. In contrast, the use EDTA alone or in combination with Chitosan was less effective at controlling Enterococcus faecalis than the antibiotic extenders, which also resulted in a reduction of sperm total motility over storage period (0–72 h) and negatively impacted fertility rate and total kits born. Conclusions: Chitosan’s protective effect on sperm function, combined with its antimicrobial activity, makes it a promising alternative antimicrobial agent for the liquid storage of rabbit seminal AI doses