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Green spaces in urban areas, such as parks and gardens, provide recreational, social, and health benefits for more than half of the world's inhabitants. Arthropods in urban vegetation may cause some disruption to humans but also provide vital ecological services such as biological control and pollination. However, little is known about the ecology of urban pests, their natural enemies, and how to manage them in an ecofriendly manner, especially in Southern Europe. In this review article, we consider the information available concerning the biological control of aphids in the urban green areas of Spain, mainly focusing on the different aphid species, their natural enemies (and how to enhance them), and the sampling methods used to study them. A wide range of aphid species is found in Spain, but only a few are responsible for the majority of damage (so-called k-aphids, most of which are holocyclic species), and these show two distinct injury profiles (short and long) that determine monitoring and control strategies. Urban aphids have numerous natural enemies, including more than 20 species of ladybeetles, as well as predatory hoverflies, midges, lacewings, bugs, and other groups. More than 40 species of aphid parasitoids and their tritrophic aphid plant associations have been reported. The availability and usefulness of commercially reared aphid natural enemies is discussed, and two methods to enhance natural enemies are described. We also review aphid sampling methods developed for urban green spaces. The studies provide basic information on the ecology of aphids to support conservation biological control as a reliable strategy in the urban green areas of Spain. [ABSTRACT FROM AUTHOR]

The alfalfa virome has been understudied. Existing research dealing with viral incidences within the crop primarily concentrate on local factors, rather than considering a broader perspective. In this comprehensive 2‐year study, we define the alfalfa virome and the main local and landscape factors affecting the incidence and annual increase of the Alfalfa mosaic virus (AMV), the most prevalent virus in alfalfa. The study was conducted in commercial alfalfa fields located along the highly productive northeast region of the Iberian Peninsula. For the first time in Europe, next‐generation sequencing revealed the presence of 14 different viruses representing the genera Cytorhabdovirus, Alphapartitivirus, Amalgavirus, Alfamovirus, Luteovirus, Enamovirus and Flavivirus. AMV was the most prevalent species, accounting for 89% of the identified viral contigs. Enzyme‐linked immunosorbent assays showed that the incidence of AMV varied between fields, with the average incidence doubling from 34% in 2019 to 65% in 2020. To assess the effect of local and landscape characteristics on the incidence of AMV and the observed annual increase, we selected different local variables and recorded landscape structure at three different buffer radii (250, 500 and 1000 m) from the centre of each field. Both the incidence and annual increase in AMV were driven mainly by local characteristics. The incidence of AMV showed a significant relationship with crop age and field area, whereas the annual increase was mainly influenced by crop age and the cumulative number of alate morphs of the aphid Acyrthosiphon pisum. Only one landscape composition variable, the percentage of alfalfa, showed a significant relationship with AMV incidence at the 250‐m scale. These results confirm the effect of local variables on the population structure of generalist viruses. [ABSTRACT FROM AUTHOR]