Aphids affect citrus by causing leaf deformations and reducing fruit production. Additionally, aphids are a great concern due to their ability to transmit Citrus tristeza virus (CTV), the cause of tristeza, one of the main citrus diseases. In the last four years, citrus orchards in the south of Portugal (Algarve region) were sampled for aphid species identification and counting. Aphis spiraecola was the most abundant species, representing more than 80% of all identified aphids, and the damage (leaf deformation) it causes was directly proportional to its density. A. gossypii was the second most common species, followed by A. aurantii and Macrosiphum euphorbiae. The number of aphids in nymph stages was predominant over the adult stages (both wingless and winged) in all species. A. citricidus, the most efficient CTV vector, was not detected. The largest populations of A. spiraecola were observed in lemon and orange trees during spring (>100 individuals per shoot), with great damage observed in orange, lemon, and mandarin trees. A. gossypii was observed mainly in mandarin and tangor trees. There was a low activity of natural biological control agents, with the parasitism of A. spiraecola by Lysiphlebus spp. and Binodoxys spp. ranging from 0.3 to 1.5%. The numerical ratio ranged from 150 to 440 aphids per predator, and among these, syrphids were the most abundant, followed by lacewings and coccinellids (Scymnus).

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 occurrence of 71 species of Psylloidea in Portugal (mainland and islands) is documented based on a critical review of literature sources and the examination of recently collected and museum material. The following 17 species are reported from Portugal for the first time: Acizzia acaciaebaileyanae, Aphalara polygoni, Arytaina genistae, Arytainilla delarbrei, Bactericera nigricornis, B. substriola, B. trisignata, Cacopsylla alaterni, C. perrieri, Colposcenia tamaricis, Livia mediterranea, Livilla maculipennis, Macrohomotoma gladiata, Psylla foersteri, Psyllopsis fraxinicola, Trioza centranthi and T. eugeniae. Among the literature records reviewed, four are questionably assigned to particular psyllid genera or species, two probably refer to psyllids and six probably do not concern psyllids. Five species records in the literature are erroneous even though some of the species may occur in Portugal. The following synonymies are proposed: Bactericera Puton, 1876, = Phylloplecta Riley, 1884, syn. nov., = Sinitrioza Yang & Li, in Li & Yang, 1984, syn. nov. These synonymies entail following new or revived combinations: Bactericera chunghsingica Lauterer, Yang & Fang, 1988, comb. rev.; B. occidentalis (Tuthill, 1939) comb. nov.; B. rubicola (Tuthill, 1943) comb. nov.; B. rubisuga (Yang & Li, in Li & Yang, 1984) comb. nov.; B. stylifera (Patch, 1912) comb. nov.; B. tripunctata (Fitch, 1851) comb. nov. and B. trisignata (Löw, 1886) comb. rev. While the fauna of Madeira is relatively well documented, this is not the case for that of the Azores and particularly of the mainland.

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.

The ‘Encore’ mandarin tree, cultivated in Portugal for long time, valued for its flavour and later ripening period, faces challenges due to a rind‐stain disorder affecting its external appearance. Despite its favourable attributes, the emergence of new cultivars such as ‘Nadorcott’, free from external appearance problems and with overlapping ripening periods, resulted in the marginalization of ‘Encore’ in the market. Major retailers, by prioritizing consumer preference for appearance, have contributed to the decline in ‘Encore’ cultivation. Despite this, the ‘Encore’ mandarin is still preferred by long‐standing consumers who remember its greater availability in previous decades and value its characteristic taste. Currently, its distribution is mainly restricted to local markets and small‐scale fruit retailers. To gauge consumer preference, we conducted a tasting and questionnaire survey with 131 randomly chosen participants, comparing ‘Encore’ and ‘Nadorcott’. The findings revealed a clear consumer preference for the external appearance of ‘Nadorcott’, leading to a preference for purchasing it based on this criterion alone. Conversely, when evaluating internal fruit quality, consumers distinctly favoured ‘Encore’ for its aroma, sweetness, acidity and overall taste. They expressed a preference for purchasing it based solely on internal quality. However, when participants learnt that less visually appealing fruits were equivalent to the more desirable ones internally, their purchase intentions became indifferent towards both cultivars, with no significant difference observed. This highlights the complex interplay between perceptions of external appearance and internal organoleptic quality among consumers, challenging the assumption that appearance alone dictates purchasing decisions.

PD Dr Daniel H. Burckhardt (Figs 1–4) turned 70 on 26 July 2023. His extensive body of work on the taxonomy of insects, initiated even before his doctoral thesis on Western Palaearctic Aphalaridae in 1983, has since expanded to encompass all major psyllid groups (Hemiptera: Sternorrhyncha: Psylloidea), both extant and extinct, but also moss bugs (Hemiptera: Coleorrhyncha) and several families of beetles (Coleoptera, mainly Passandridae, but also Jacobsoniidae, Pterogeniidae and Staphylinidae). These contributions have had a profound and lasting impact on our global understanding of these relatively small and often overlooked groups of insects. The biographical details of Daniel Burckhardt’s career and life will not be revisited here, as they have already been thoroughly documented elsewhere. In terms of his tireless dedication and remarkable productivity, the comprehensive list of his publications at the end of this article speaks for itself. Another telling measure of his influence within entomology is the number of PhD students he has mentored, formally or informally, many of whom have gone on to establish successful careers in leading research institutions and natural history museums across Europe and beyond. At a time when taxonomic expertise is rapidly declining, with serious implications for biodiversity research, agriculture and conservation, his intellectual legacy, marked by rigour, precision, and clarity, has been effectively passed on to the next generation. This tribute aims above all to highlight the personal and professional impact Daniel Burckhardt has had on so many colleagues and collaborators. Rather than a conventional biography, it offers a space for those who have worked with him to share their experiences and anecdotes, and to reflect on the influence he has had on their scientific journeys.