## 2 Fusarium Head Blight (FHB)
### FHB in the US  
_Fusarium graminearum_ literally 'fusarium of the grasses' [26] has been named among the most threatening plant pathogenic fungus in the world because of its aggressiveness and its economic importance [47; 48]. It threatens some of the major global producers of wheat that are coincidentally in some of the most FHB prone areas. In these regions severe FHB epidemics occur at a minimum of every fourth or fifth year [49] resulting in great losses. A concise history of major epidemics in North America is shown in (Figure 1). Dating back to the early 20 th century, the US saw a steady increase in FHB epidemics that was mostly concentrated in the Eastern, Northern, and Central Midwest states of Iowa, Ohio, Indiana, and Illinois [28; 29; 33]; however, the swift spread of FHB epidemics of 1917 and 1919 did not serve to many as a harbinger of the indomitable and imperceptible nature of this disease. At the turn of the new decade, in the 1920s, the disease then quickly raced its way into many wheat fields of the Upper Midwest states of Minnesota, North and South Dakota, and the East South-Central state of Kentucky before resting comfortably but disastrously in the Midwest [33]. The mid of the 20 th century saw a well needed repriere from the devastating epidemics of the last decades; however, this repriere was short lived and frequent FHB epidemics returned in the 1970s and extended its grip into the Northeastern and South Atlantic provinces of Pennsylvania, Maryland, and Virginia [33]. Figure 1. A timeline of the major Fusarium Head Blight (FHB) epidemics in the USA over the last 100 years. A brief description of the major FHB epidemics in the USA covering a period of 107 years. The diagram above is a condensed version showing FHB epidemics from 1917 to 2007. By the 1980s FHB epidemics were reported in as far as New York. The epidemic of 1982 resulted in a 4% reduction in the total US wheat production equivalent to 2.72 million metric tonnes or 100 million bushels [28]. This was by far the worst epidemic the US had experienced since the epidemics of 1919 and 1928, the latter of which mostly affected barley crop resulting in significant international trade disturbances [28; 33]. As the curtains closed on the 20 th century the frequent outbreaks and epidemics had scarcely left any wheat-producing states unscathed. FHB in the 1990s would go on record to be some of the worst epidemic years both in terms of crop damage and economic losses in North America and the global wheat industry [26; 28; 29; 32]. By this time FHB outbreaks had touched most if not all the cereal crop producing states in the US. The unparalleled and social impacts caused by the 1993 epidemic has been described and documented in numerous articles [26; 28; 33; 50] to mention a few. The 1993 epidemic resulted in an estimated $1 billion USD loss to producers in the tri-state areas of Minnesota, North and South Dakota, making it the greatest loss compared to any other plant disease in North America in a single year [28]. From then on at the close of the 20 th century, FHB wreaked havoc on wheat, durum wheat and barley in the US which also extended to the Canadian prairie province of Manitoba. At the end of this prolonged epidemic period, it was estimated that over 500 million bushels or 13.6 million metric tonnes of wheat valued at $2.5 billion was lost [28], which at present is approximately equivalent to 4 years supply for food and industrial use, based on the 2015-2019 consumption data from Statistics Canada and Agriculture and Agri-Food Canada [51]. The economic significance and cataclysmic loss caused by this disease overshadowed the disastrous epidemics just a decade earlier in 1982, in which it was estimated that 100 million bushels or 2.72 million metric tonnes of wheat was lost due to FHB [50; 52]. Losses resulting from the 1991-1996 FHB epidemics were estimated to be around 7.67 billion USD, the most expensive loss to date [9; 29]. At the dawn of the 21 st century the science of plant pathology was better prepared to deal with FHB.