The cultivation of citrus in the Mediterranean region is of considerable economic importance. The viability of this industry is contingent upon a number of factors, with adequate phytosanitary management being of particular significance. During the last decade, the geographical range of the invasive psyllid, Trioza erytreae (Del Guercio, 1918), has expanded to the mainland territories of Portugal and Spain. Trioza erytreae acts as a vector for the Huanglongbing disease (HLB). This review presents the current knowledge about the hosts of the psyllid and their attractiveness and suitability. A classification of the hosts according to their suitability, as assessed in the literature, is provided. The attributes of the hosts and the methods used to assess their suitability are described, as well as the climatic factors that affect the psyllid–host interaction. The review emphasises the importance of a comprehensive evaluation of the interactions between the psyllids and their hosts to develop and implement more effective strategies for controlling T. erytreae.

Huánglóngbíng (HLB; citrus greening) is the most damaging disease of citrus worldwide. While citrus production in the USA and Brazil have been affected for decades, HLB has not been detected in the European Union (EU). However, psyllid vectors have already invaded and spread in Portugal and Spain, and in 2023 the psyllid species known to vector HLB in the Americas was first reported within the EU. We develop a landscape-scale, epidemiological model, accounting for heterogeneous citrus cultivation and vector dispersal, as well as climate and disease management. We use our model to predict HLB dynamics following introduction into high-density citrus areas in Spain, assessing detection and control strategies. Even with significant visual surveillance, we predict any epidemic will be widespread on first detection, with eradication unlikely. Introducing increased inspection and roguing following first detection, particularly if coupled with intensive insecticide use, could potentially sustain citrus production for some time. However, this may require chemical application rates that are not permissible in the EU. Disease management strategies targeting asymptomatic infection will likely lead to more successful outcomes. Our work highlights modelling as a key component of developing epidemiological preparedness for a pathogen invasion that is, at least somewhat, predictable in advance.

The psyllid Trioza erytreae is a vector for Huanglongbing, one of the most destructive citrus diseases worldwide. Citrus × limon is the preferred host, although the mechanisms underlying this preference remain poorly understood. This study compared the responses of C. × limon 'Eureka' and C. × sinensis 'Valencia' plants to T. erytreae infestation, specifically to nymph feeding. The number of successfully developed nymphs observed in C. × limon was three times that of 'Valencia' plants. The enriched vascular sap proteome of young leaves from infested and control plants was compared using nanoscale liquid chromatography coupled to tandem mass spectrometry. This study identified 48 and 1265 differentially abundant proteins (DAPs) in infested C. × limon and C. × sinensis, respectively. There was a marked host-specific response, with little overlap in proteomic features. Common citrus host responses to infestation were the downregulation of 'Amino sugar and nucleotide sugar metabolism' and the upregulation of galactose, vitamin B6, and selenocompound metabolisms. The downregulation of photosynthesis-related proteins and the activation of defence-related pathways in C. × sinensis suggest a robust response, which may explain the low success rate of nymph development on this host. The lower number of DAPs in C. × limon infested with T. erytreae, in comparison to the respective control, may be indicative of a reduced stress response. Further investigation into the identified candidate proteins and pathways is expected to contribute to the elucidation of the interaction between T. erytreae and C. × limon.

The wild dioecious plant Corema album, endemic to the Atlantic coast of the Iberian Peninsula, has potential to become a new crop and to integrate the berry fruit market. Due to its potential, the aim of this study was to propose a BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemical Industry) scale for the species. Based on field observation, the principal growth stages were described and sequentially established. Photographs and stereomicroscope acquisition software were used to illustrate the phenological stages of male and female plants. The scale includes seven principal stages starting with bud development (stage 0), followed by leaf development (Stage 1), main stem elongation (Stage 3), inflorescence emergence (Stage 5), flowering (Stage 6), fruit development (Stage 7) and ending with fruit maturation (stage 8), with mesostages for male and female inflorescence (stage 5) and flower development (stage 6). Through field observations carried out in plants in different growth conditions, the proposition of this extended BBCH scale was made, to have a standardized system for Corema album phenological stages. This study will have an application especially in fields of agronomy and plant breeding and will also be a stepping stone for the inclusion of this species as a novelty crop in a nearby future.

In the context of global population growth and intensifying climate change, ensuring food security remains a critical challenge. Orchards are more productive than arable crops, contributing significantly to the nutrition of a growing population. Ecologically, due to the absence of frequent soil tillage, orchards resemble natural forest ecosystems more closely than other agricultural systems. Irrigated orchards are particularly productive and enhance biodiversity in territories where water scarcity is the limiting factor for ecosystems. This review, the result of extensive reflection and a comprehensive analysis of the literature on orchard sustainability, synthesizes evidence on the diverse ecosystem services provided by these perennial systems. Due to their structural complexity, well-managed orchards contribute significantly to climate regulation through carbon sequestration, microclimate cooling, and soil erosion prevention. Furthermore, they support nutrient cycling and provide cultural value. This paper establishes an integrated scientific framework to inform evidence-based policies and reshape societal perceptions. It argues that recognizing orchards as multifunctional landscapes, rather than mere resource consumers, is critical for environmental resilience, supporting their fair valuation as essential components of a sustainable bioeconomy.