Abdelhak Rhouma

Fire blight, caused by Erwinia amylovora, is a devastating bacterial disease affecting pear orchards and has been reported in Tunisia since 2012/2013. Accurate prediction of infection risk is essential for timely disease management. This study aimed to develop forecasting models that correlate epidemiological factors with local microclimatic conditions in a Tunisian pear orchard. The study was conducted in a pear orchard in Ouerdanine (Monastir, Tunisia) from March to June 2023, on the ‘Alexandrine’ variety. Weekly epidemiological monitoring was performed, and disease severity was quantified using a standardized index based on a scale of 0 to 6. An autonomous weather station continuously recorded ambient temperature, flower-level temperature, and relative humidity, which are key variables for pathogen development. Two predictive models were developed after careful data preparation and normalization: (1) a tree-level model using machine learning algorithms, including Decision Tree, Random Forest, and Support Vector Machine, based on individual sensor measurements, and (2) an orchard-level model using Linear Regression with aggregated satellite meteorological data. Local microclimatic conditions strongly influenced disease severity. Machine learning models showed moderate performance in predicting infection at the individual tree level, with the Decision Tree algorithm achieving the highest accuracy (48%), followed by Random Forest (44%) and SVM (29%). The regression model provided reliable estimates of overall orchard severity, allowing for the assessment of disease trends at a larger scale. These forecasting models, adapted to the Tunisian Mediterranean climate, offer practical tools for fire blight management. They can help optimize the timing of chemical and biological preventive measures, improving control of this major phytosanitary threat. However, further validation across multiple orchards, varieties, and seasons is needed to confirm their broader applicability. This approach demonstrates the potential for adapting established models to local conditions in Tunisia.

This study investigated the prevalence and impact of Fusarium dry rot, a significant postharvest disease of potatoes. The objectives of this research were to determine the primary Fusarium species causing dry rot in potato markets and to assess the antagonistic potential of selected bacterial biocontrol agents against the dominant pathogen. Market surveys revealed significant disease losses, with Islamabad exhibiting the highest incidence (17.2-19%). Fusarium species, particularly F. subacianum (62.50%), F. oxysporum (57.50%), and F. solani (56.25%), were identified as the primary pathogens. Pathogenicity tests confirmed the virulence of these isolates, with F. oxysporum (45 mm) demonstrating the highest aggressiveness. To explore biological control options, three bacterial strains (Pseudomonas fluorescens, Bacillus velezensis, and Bacillus subtilis) were evaluated for their in vitro and in planta antagonistic activity against F. subacianum. Their efficacy was assessed through in vitro dual-culture assays and in planta experiments on potato tubers using both preventive and curative application methods. B. velezensis exhibited the strongest in vitro inhibition of fungal growth (74.91%) and demonstrated the most effective disease control in both preventive (14.28%) and curative (16.82%) applications on potato tubers. The demonstrated efficacy of B. velezensis underscores its potential as a sustainable biocontrol tool, offering a viable strategy to reduce postharvest losses and minimize reliance on synthetic fungicides in potato storage systems.

Mycotoxins are toxic secondary metabolites produced by filamentous fungi, primarily belonging to the genera Aspergillus, Fusarium, and Penicillium, which contaminate agricultural commodities during postharvest storage and processing. These toxins pose severe health risks to humans and livestock, including carcinogenic, hepatotoxic, nephrotoxic, and immunosuppressive effects. Affluents, ochratoxin A, fumonisins, zearalenone, and deoxynivalenol are among the most concerning mycotoxins, each associated with specific diseases such as liver cancer, kidney damage, and hormonal disruptions. Contamination typically occurs under poor storage conditions, including high humidity, inadequate drying, temperature fluctuations, and insect infestations, which facilitate fungal proliferation and toxin production. Despite advances in food safety, the stability of mycotoxins during processing and cooking remains a persistent challenge. This review comprehensively examines the major mycotoxins, their health impacts, and factors contributing to postharvest contamination. In addition, it explores current detection methods, such as chromatographic techniques and rapid immunoassays, alongside emerging biosensor technologies. Mitigation strategies for mycotoxin-resistant crops are discussed in detail, including improved storage practices (hermetic sealing, controlled atmospheres), biological control (antifungal microbes, competitive exclusion), chemical treatments (organic acids, ozonation), and innovative approaches such as nanotechnology and genetic engineering. The review emphasizes the need for an integrated approach that combines pre- and post-harvest interventions to minimize mycotoxin exposure and ensure global food security. Regulatory frameworks, including Codex Alimentarius and FDA guidelines, are also highlighted to underscore the importance of compliance with safety standards. By synthesizing current research and technological advancements, this study aims to provide actionable insights for reducing mycotoxin contamination in the food supply chain.

Soil degradation poses a critical threat to global food security and ecosystem function. Biochar, a carbonaceous material derived from the thermochemical conversion of biomass under oxygen-limited conditions, has emerged as a promising soil amendment to address this challenge. This comprehensive review examines the role of biochar in enhancing soil health through its multifaceted impacts on soil properties. We detail how biochar's inherent characteristics—such as its high specific surface area, porosity, alkaline pH, and cation exchange capacity —directly improve the soil physical environment by reducing bulk density, enhancing water retention, and promoting aggregation. Chemically, biochar acts as a soil conditioner, increasing pH in acidic soils, improving nutrient retention to reduce leaching losses, and immobilizing contaminants. Biologically, its porous structure provides a protective habitat for beneficial microorganisms, thereby stimulating microbial biomass, enhancing arbuscular mycorrhizal fungi colonization, and boosting enzymatic activity fundamental to nutrient cycling. These mechanisms collectively translate into significant agricultural benefits, including improved crop yields and increased plant tolerance to drought and disease. Furthermore, biochar's makes it a direct tool for long-term carbon sequestration, aiding in climate change mitigation. Despite its promise, the variable nature of biochar properties, risks of over-application, and economic costs present substantial hurdles to large-scale implementation. Therefore, future research must prioritize the development of tailored "designer biochars," long-term field studies, and supportive policy frameworks to integrate biochar effectively into sustainable agricultural systems worldwide.

Background and purpose: Root Knot Nematodes (RKN) hamper plant growth and productivity. They are basically managed by chemicals arising environmental and health concerns. Material and methods: Pots and greenhouse experiments were conducted to test the bio-control effect of Trivago SC20 (based on abamectin derived from Streptomyces avermitilis) and Myco-up attack (based on Glomus iranicum var tenuihypharum mycorrhizae compared with the two nematicides [Vydate® (oxamyl) for pot assay and Mocap® (ethoprophos) for greenhouse assay] in controlling Meloidogyne javanica infesting tomato. Gall index, gall number /g root, egg-masses /g root, RKN /g root, multiplication rate, M. javanica density, nematodes groups frequency, hatched eggs/ egg masses, agronomic and production traits were studied to determine the efficiency of arbuscular mycorrhizal fungi (AMF) and abamectin compared with the fungicide application. Results: The first experimental results showed that high nematode suppression was provided by G. iranicum and abamectin treatments. Both bio-nematicides were also effective in the control of M. javanica naturally infested tomato plants under greenhouse conditions. Besides, the G. iranicum and abamectin had a positive effect on plant growth because of stimulation of plant vegetation parameters, such as the shoot weight and root length. Furthermore, the AMF satisfactorily colonized the tomato roots. Conclusions: Hence, tested abamectin and mycorrhizae-based products may be used for M. javanica management programs as an alternative and eco-friendly approach to fungicides, while preserving the environment.

Plant diseases pose a significant threat to global agriculture, food security, and environmental sustainability, causing substantial economic losses and ecological disruptions. This review paper provides a comprehensive overview of the major types of plant diseases, their causative agents, and the complex interplay of factors that influence their development and spread. Fungal, bacterial, viral, nematode, and other microbial pathogens are examined in detail, highlighting their unique characteristics, modes of infection, and the challenges they present to disease management. The economic impacts of plant diseases are profound, with annual global crop losses estimated at billions of dollars, threatening the livelihoods of millions of farmers and exacerbating food insecurity, particularly in vulnerable regions. Historical examples, such as the Irish Potato Famine and the ongoing threat of Panama disease, underscore the devastating consequences of unchecked plant diseases. Ecologically, plant diseases disrupt ecosystems, reduce biodiversity, and alter ecosystem functions, as seen in the near-extinction of the American chestnut due to chestnut blight and the spread of sudden oak death in North American forests. The social consequences of plant diseases are equally significant, contributing to poverty, migration, and food shortages, particularly in developing countries where agriculture is a primary source of income and nutrition. The review also explores current and emerging strategies for managing plant diseases, emphasizing the importance of integrated and sustainable approaches. Biological control, cultural practices, chemical treatments, and genetic engineering are discussed as key components of effective disease management. Emerging technologies, such as remote sensing, artificial intelligence, nanotechnology, and microbiome engineering, offer innovative solutions for early detection, targeted control, and enhanced plant resilience. The paper concludes by highlighting the need for global collaboration, research, and policy support to address the evolving challenges posed by plant diseases. By integrating scientific innovation, sustainable practices, and inclusive policies, we can mitigate the impact of plant diseases, protect ecosystems, and ensure food security for future generations. This review underscores the critical importance of plant disease management in building resilient agricultural systems and promoting environmental and social well-being in the face of global challenges.

This study investigated the potential of Trichoderma koningii and Rhizophagus irregularis as environmentally friendly as an alternative to chemical control for Fusarium wilt disease in tomato under greenhouse conditions. The research focused on how these T. koningii and R. irregularis interacted and their impact on plant growth and disease resistance. T. koningii alone significantly reduced disease severity (DS = 0.83; DSI = 29.33%) compared to the control group infected with Fusarium oxysporum f. sp. lycopersici (FOL). However, the most effective protection came from combining both T. koningii and R. irregularis (DS = 0.33; DSI = 14.33%), achieving a level comparable to healthy controls. This combined treatment not only displayed superior disease resistance but also showed the highest chlorophyll content (Chl a = 5.62 mg g-1 Fresh Weight; Chl b = 3.11 mg g-1 Fresh Weight; Chl T = 8.74 mg g-1 Fresh Weight), indicating a stronger ability to counteract the chlorophyll degradation caused by FOL infection. Furthermore, tomato plants co-inoculated with T. koningii and R. irregularis exhibited the most robust antioxidant response, evident in significantly higher activities of antioxidant enzymes (superoxide dismutase = 46.17 units g-1 ml-1 min-1, peroxidase activity = 5.66 units g-1 ml-1 min-1, and catalase activity = 104.42 units g-1 ml-1 min-1) and total phenolic content (3.14 mg g-1). These findings suggest that the combined application of T. koningii and R. irregularis has the potential to be a more effective and environmentally friendly strategy for managing Fusarium wilt disease and promoting overall plant health in tomato compared to using either T. koningii or R. irregularis alone.

Fungal phytopathogens pose a significant and escalating threat to global food security, resulting in considerable crop losses and economic burdens while challenging the sustainability of conventional chemical-dependent management practices. This review synthesizes current advancements and challenges in the development of safe, practical strategies to control fungal plant diseases, underscoring the urgent necessity for sustainable alternatives. We examine the potential of biological control agents, host resistance breeding, natural antifungals, nanotechnology, and cultural practices as environmentally friendly solutions, while also highlighting the limitations of synthetic fungicides, which include the development of resistance and ecological detriment. The paper emphasizes the critical importance of Integrated Pest Management in harmonizing these approaches, leveraging synergies among microbial inoculants, genetic innovations, and precision agriculture to diminish dependence on chemical inputs. Despite promising innovations—such as CRISPR-edited crops, RNAi-based fungicides, and nano-formulated biocontrol agents—significant barriers remain, including inconsistent field performance, regulatory challenges, and socioeconomic constraints. We also discuss emerging solutions, encompassing microbiome engineering and climate-resilient biocontrol strains, and underscore the necessity of policy reforms and farmer education to facilitate widespread adoption. Ultimately, this review advocates for a paradigm shift towards ecologically balanced disease management, arguing that the integration of advanced technologies with traditional knowledge can cultivate resilient agricultural systems capable of addressing future food demands while safeguarding ecosystem health. The findings offer a comprehensive roadmap for researchers, policymakers, and practitioners to transition from reactive fungicide use to proactive, sustainable management of fungal pathogens.

Environmental changes are causing shifts in the species distributions on a global scale and can alter the interactions between the microorganisms within ecosystems. The ecosystem comprised a complex web of species with diverse life history strategies and varying dispersal capabilities. Therefore, it is improbable that all species respond to climatic changes identically. Climate change disrupts the delicate balance of plant-soil ecosystems, which significantly affecting plant health and soil fertility. However, the effects on the intricate web of soil microbe-microbe interactions remain largely unknown. The crucial role of soil microorganisms in nutrient cycling, plant nutrition, facilitation of plant coexistence, and population regulation could have significant consequences for plant community composition and overall ecosystem function. This study focuses on climate-changes, which directly and indirectly have effects on soil microbes and their interactions with plants. We identify emerging questions and areas for future exploration, while evaluating the potential ramifications of changing these interactions on the composition and function of the ecosystem. Overall, this study has the potential to contribute to our understanding significantly of climate-changes effects on ecosystems and pave the way for the development of effective strategies to mitigate these effects and ensure the continued health and function of our ecosystem.