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Root rot is a concern in the pea growing areas of Canada and elsewhere in the world, since it can cause significant yield loss. Fusarium spp. are considered major pea root rot pathogens. In this study, the pathogenicity and host range of Fusarium species collected from earlier surveys of commercial pea fields in Alberta were evaluated. Forty-five isolates belonging to six Fusarium species were selected for pathogenicity testing under greenhouse conditions. Fusarium solani f. sp. pisi and F. avenaceum were the most aggressive species, followed by F. oxysporum, F. culmorum and F. redolens. Due to their ability to cause severe disease on pea, F. solani f. sp. pisi and F. avenaceum were chosen for further testing on other common rotational crops grown in Alberta, and 10 cereal, oilseed and pulse crops were inoculated with isolates of those species. Both F. solani f. sp. pisi and F. avenaceum caused significant disease symptoms on pea, chickpea, dry bean and faba bean, but not on cereal crops, soybean, green lentil or canola when compared with their respective non-inoculated controls. Fusarium avenaceum, but not F. solani f. sp. pisi, caused significant root rot symptoms on red lentil, although disease severity was low. New information on the host range of these root rot pathogens will be valuable for choosing appropriate disease management strategies. [ABSTRACT FROM AUTHOR]

Abstract Soybean (Glycine max (L.) Merr.) has been a commercial oilseed crop in Canada since the 1920s. The production of soybean rapidly increased from 2004 to 2016 in Alberta and Manitoba. Root rot disease caused by the oomycete genus Pythium was observed from 105 fields in 2015 and 2016 in southern Alberta and Manitoba. In the present study, a total of 97 isolates of Pythium were recovered from the root tissues of soybean seedling collected from those fields. Identification of the Pythium species was achieved by examining their morphological features and sequences analysis of internal transcribed spacers (ITS) and cytochrome oxidase subunit 2 gene (Cox II). Nine species of Pythium were identified, with Pythium violae as the predominant species (27 out of 97, 27.8%), followed by P. intermedium (21), P. irregulare (16), P. sylvaticum (12), P. recalcitrans (8), P. ultimum (8), P. heterothallicum (3), P. conidiophorum (1) and P. macrosporum (1). This is the first report of P. conidiophorum , P. recalcitrans and P. violae on soybean in Canada. All the Pythium isolates except three isolates (S2d of P. violae , S29a and S29b of P. heterothallicum) were highly virulent on soybean, causing root rot disease symptoms. Highlights • Obtained 97 Pythium isolates from soybean in Alberta and Manitoba from 2015 to 2016. • Pythium violae was predominant within nine identified Pythium species. • First report of P. conidiophorum , P. recalcitrans and P. violae in soybean in Canada. • All of the Pythium isolates were able to infect soybean with varied aggressiveness. [ABSTRACT FROM AUTHOR]

Soybean ( Glycine max (L.) Merr.) has excellent potential as an alternative crop to canola in southern Alberta farming systems. However, soybean is susceptible to Fusarium root rot, which usually results in the occurrence of dead or dying plants in mid-to-late summer and severe reductions in yield. A total of 102 isolates identified as Fusarium were recovered from diseased soybean root samples collected from central and southern Alberta from 2011 to 2013. Ten species of Fusarium were identified, with F. acuminatum as the predominant species (31 out of 102 isolates, 30.39%), followed by F. equiseti (16.67%), F. culmorum (13.73%), F. avenaceum (10.78%), F. oxysporum (8.82%), F. redolens (7.84%), F. torulosum (4.90%), F. tricinctum (2.94%), F. commune (1.96%) and F. proliferatum (0.98%). This is the first report of F. commune , F. redolens and F. torulosum causing root rot in soybean in Canada. Phylogenetic analyses based on sequence data from the translation elongation factor 1-α (EF-1α) and the internal transcribed spacer (ITS) region were used to evaluate genetic variation and, in conjunction with morphological characters, for species identification. All of the Fusarium isolates were able to infect soybean, although some exhibited varying levels of aggressiveness. [ABSTRACT FROM AUTHOR]

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Abstract: Ascochyta blight, caused by a complex of Mycosphaerella pinodes, Phoma pinodella, Ascochyta pisi, and/or Phoma koolunga, is a devastating disease of field pea. In order to understand the composition of fungi associated with ascochyta blight in Alberta, Canada, a total of 157 single-pycnidiospore fungal isolates were obtained from diseased pea samples collected from central and northern Alberta in 2011. These isolates were characterized for species identity, aggressiveness, DNA sequence variation in the internal transcribed spacer (ITS) region, and random amplification of polymorphic DNA (RAPD) patterns. The ITS sequences obtained from 142 fungal isolates were all identical to the ITS sequences from M. pinodes and/or P. pinodella. Inoculation of the 157 isolates on a susceptible pea cultivar Midas indicated that most of the isolates were moderately to highly aggressive. Phylogenetic analysis based on the RAPD data revealed two main groups and six sub-groups, with one main group comprising 78% of the 157 isolates. Distinct RAPD patterns were associated with isolates from particular geographic locations, but were not generally associated with isolate aggressiveness. [Copyright &y& Elsevier]

Isolates of Fusarium spp. were recovered from the roots of field pea ( Pisum sativum) collected from 15 commercial fields in Alberta, Canada. Most of the isolates (75 out of 96) were identified as F. avenaceum, based on morphology, phylogeny and species-specific PCR amplification. Molecular differences in the F. avenaceum isolates were detected based on putative mating type, and on ITS and CPN60 sequences. MAT-1 and MAT-2 were equally distributed among the isolates. Phylogenetic analysis based on ITS and CPN60 sequences clustered most of the F. avenaceum isolates into a single group. In some cases, isolates with low aggressiveness clustered together in additional groups. There was no correlation between phylogenetic profile and either mating type or geographic origin. This population of F. avenaceum has a low level of genetic variation and consists of isolates derived from the two mating types. Isolates with low aggressiveness are also retained in the population. [ABSTRACT FROM AUTHOR]