## 3 Mycotoxicigenic Fusarium Pathogens  
In Canada and North America as well as many other regions in the world, _F. graminarium_ is the predominant pathogenic species that causes FHB in wheat and barley [33; 47; 55]. _F. graminearum_ is a highly virulent hemibiotrophic pathogen that produces type B trichothecenes, deoxynivalenol (DON) and its acetylated derivatives 3 ADON and 15 ADON, nivalenol (NIV), and zearaleno (ZEN) [56; 63; 64; 65; 66]. These are some of the most important fungal toxins that have been known to contaminate cereal grains and other crops that are prepared for human and animal consumption. DON also known as vomitoxin, is the most observed toxin in Canadian grain [60; 67]. Several studies have described the adverse health effects experienced by humans and animals upon exposure to varying levels of DON [33; 48; 55]. DON has been linked to feed refusal and weight loss in pigs [33; 67]. In humans, DON has been identified as the causal agent in vomiting, diarrhea, neural disturbances [27], liver and kidney damage, immune and nervous system impairment [27] after the consumption of contaminated food. In addition to its adverse effects on mammals, DON has been reported to increase the virulence of _F. graminearum_ on wheat and durum [67; 68; 69]. Canadian prairies, studies on wheat and durum showed that there was a significant relationship between DON levels and visible _Fusarium Damage_ (FUS DMG) in Canadian Western Amber durum (CWAD) and most Canadian Western Red Spring (CWRS) [61]. The FUS DMG and DON relationship is currently used as grading factor for grains produced in Canada as implemented by the Canadian Grain Commission (CGC) [61; 70]. However, conclusions on the FUS DMGand DON relationship as a gold standard grading factor for harvested grains remain equivocal, since different studies have shown that the relationship is not always linear [71]. In the same study carried out in the Canadian prairies, [PERSON] et al. (2019) reported that the relationship between FUS DMG and DON was at times variable [60]. In one of the wheat districts, the low concentration of DON measured did not correspond to the high level of FUS DMG seen in CWRS of that district. Additional data showed that a variation in _Fusarium_ species resulted in a variation of mycotoxins detected at any given time. This variation was attributed to prevailing environmental conditions such as precipitation and high temperature in the growing year which was ideal for the growth of some _Fusarium_ species over others. Indeed, visible FUS DMG is not always correlated to DON concentration, signifying that species other than _F. graminearum_ and _F. culmorum_ can produce visible FUS DMG [61]. These findings suggest that to effectively combat or implement integrated strategies to manage FHB and _Fusarium_ mycotoxins, there is a necessity for a more centralised reporting on mycotoxin surveillance in Canada [72]. Numerous reports will be able to give a clearer picture of the correlation, if any, between the diversity and abundance of _Fusarium_ species across the prairies and the mycotoxins produced and their concentration in wheat and durum. This information can then be used to establish a range for the concentration of _Fusarium_ toxins that can be tolerated or can be detrimental to animal and human health. In addition to type B trichothecenes such as DON, a plethora of other mycotoxins including Type A trichothecenes and Fumonisins are prevalent _Fusarium_ species mycotoxins that are observed in infected cereal grains. Deoxynivalenol- DON is mostly commonly produced secondary metabolite of (_F. graminearum_ and _F. culmorum_), Fumonisins--FUM of (_F.verticilloides_ and _F. proliferatum_), aurofusarin -AUS (_F. graminearum_, _F. poae_ and _F. sporotrichoides_), type A- trichothecenes, T-2 and HT-2 are commonly produced by (_F. poae_), beauvericin and enniatins (_F. aventaceum_, _F. poae_ and _F. sporotrichoides_), and moniliform (_F. proliferatum_ and _F. subgluitunians_) [2; 9; 27; 73].