No abstract

Summary Several Fusarium species cause harmful cereal diseases, such as fusarium head blight and crown rot, which, during pathogenesis, may result in significant grain yield and quality losses. Several species of agricultural weed are believed to be alternative and reservoir hosts for Fusarium spp.; however, studies have not comprehensively evaluated those weed species in cropping systems that may harbour these fungi. The objective of this study was to determine weed species in cereal‐based crop rotations that are asymptomatically colonised by Fusarium spp. We sampled all species of weed present in fields that were managed under six different crop sequences in 2015 and 2016. The study yielded 2326 single‐spore isolates of Fusarium spp. derived from various organs of asymptomatic weeds. Isolates were identified morphologically and then confirmed using PCR with species‐specific primers and/or sequencing of tef1α gene fragments. Isolates of nine Fusarium spp. were obtained from 689 of the 744 individuals collected that represented 56 weed species. Each weed species harboured at least one species of Fusarium, and >80% were colonised by 3–9 Fusarium spp. In total, we identified 27 dicotyledonous weed species that were previously undocumented as Fusarium hosts and 251 new weed × Fusarium species combinations were revealed. Consequently, there is a greater risk of negative Fusarium impacts on cereal crops than was previously thought. We suggest effective weed management and inversion soil tillage may help mitigate these impacts.

The Fusarium head blight emerged as the main disease of wheat in Lithuania in 2012. The chemotype diversity of FHB pathogens was not investigated prior that time. In this study chemotype determination of pure F. graminearum cultures, the main cause of FHB in wheat, isolated from grain and chemotype detection rates in homogenized grain were compared. A total of 105 pure culture F. graminearum isolates from 2013 and 144 homogenized wheat grain samples from 2013 and 2014 were analysed for presence and quantification of 15ADON, 3ADON and NIV chemotype DNA. Results show that 15ADON chemotype was clearly dominant in pure culture isolates, but not in homogenized grain, where 3ADON incidence was almost as high. Also the results allow dismissal of other toxigenic Fusarium species, F. culmorum, as either a source of NIV or the main source of 3ADON chemotype DNA in grain.

No abstract

Changes in Fusarium species composition from naturally contaminated spring and winter wheat grain from the years