Seed-borne fungal pathogens of leafy vegetable crops

Abstract

Leafy vegetables are economically important crops, with a relevant role in the diet all over the world, grown worldwide under intensive cultivation systems. In the past few years, in coincidence with the intensification of such cultivations, many new pathogens emerged, causing severe losses. Many of them are seed-borne and their transmission through infected seeds guarantees their rapid spread in different geographic areas. A relatively small percent of contaminated seeds is often sufficient to cause high disease incidence. The leafy vegetable sector is particularly exposed to the risk of the emergence of new diseases as a consequence of its dynamism, the wide range of products, continual innovation in procedures or in products and the use of intensive cultivation techniques that characterize it. Italy, with its very intensive vegetable production, represents indeed a very interesting case study. This chapter will review the situation observed in different production areas, with special reference to Italy. The crops considered are lettuce, wild and cultivated rocket, lamb's lettuce, chicory, endive, basil and spinach with particular regard to the Fusarium and Verticillium wilt agents as well as emerging leaf pathogens (Alternaria spp., Plectosphaerella cucumerina, downy mildew agents, Cladosporium variabile and Stemphylium botryosum).