A Historical Account of Viruses in Intensive Horticultural Crops in the Spanish Mediterranean Arc: New Challenges for a Sustainable Agriculture

The epidemiological dynamics followed by viruses in protected horticultural crops in the Mediterranean Arc of Spain has evolved from a majority of those transmitted by aphids to the predominance of whitefly-transmitted ones. Later, due to the shift towards an integrated control that has been quite successful in the control of aleyrodids, not so much in the control of aphids, aphid-borne viruses are having a significant revival in open field cultivation. Another threat is the continuous emergence of new species or variants of mechanically transmitted viruses. Thus, the number of viruses affecting these crops is constantly increasing and their control demands dynamic actions. The main measures that have managed to limit the damage of these diseases have been the improvement in the physical barriers that limit the spread of vectors and the introduction of resistances in the germplasm. Recently, the increased movement of plant materials and of people, the popularity of growing local crop varieties that lack natural resistances against pathogens, and the prospects of global climate change, may well have boosted the frequency of diseases and pests. Faced with this picture, strategies must be addressed from a multidisciplinary approach. The need for in-field diagnostics tools, easy access to information, novel breeding technologies and alternatives to control of these viruses are discussed.