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<i>Xylella fastidiosa</i> (<i>Xf</i>) is a vascular plant pathogen native to the Americas. In 2013, it was first reported in Europe, implicated in a massive die-off of olive trees in Apulia, Italy. This finding prompted mandatory surveys across Europe, successively revealing that the bacterium was already established in some distant areas of the western Mediterranean. To date, the Balearic Islands (Spain) hold the major known genetic diversity of <i>Xf</i> in Europe. Since October 2016, four sequence types (ST) belonging to the subspecies <i>fastidiosa</i> (ST1), <i>multiplex</i> (ST7, ST81), and <i>pauca</i> (ST80) have been identified infecting 28 host species, including grapevines, almond, olive, and fig trees. ST1 causes Pierce’s disease (PD) and together with ST81 are responsible for almond leaf scorch disease (ALSD) in California, from where they were introduced into Mallorca in around 1993, very likely via infected almond scions brought for grafting. To date, almond leaf scorch disease affects over 81% of almond trees and Pierce’s disease is widespread in vineyards across Mallorca, although producing on average little economic impact. In this perspective, we present and analyze a large <i>Xf</i>-hosts database accumulated over four years of field surveys, laboratory sample analyses, and research to understand the underlying causes of <i>Xf</i> emergence and spread among crops and wild plants in the Balearic Islands. The impact of <i>Xf</i> on the landscape is discussed.