Wheat grains are inhabited by different fungi, including plant pathogens and fungi -mycotoxin producers. The composition of seed mycobiota can be influenced by different factors, including agronomic practices, but the results are still contradictory. The aim of this study was to evaluate the mycobiota of wheat grains depending on agroecological conditions. Wheat grains were obtained from a two-factorial field trial: A -tillage system (A1 -ploughing at a depth of 22-24 cm; A2 -harrowing at a depth of up to 10 cm); B -crop rotation (B1 -continuous wheat; B2 -oilseed rape and wheat; B3 -crop rotation). The mycobiota of grain were determined by mycological and molecular methods. The most abundant and widespread of the mycobiota were Pyrenophora tritici-repentis, Alternaria spp., Arthrinium spp., and Fusarium avenaceum. Higher amounts of precipitation increased the infection of grains with Fusarium fungi. Seven species of Fusarium were identified in the grain samples: F. avenaceum, F. poae, F. graminearum, F. culmorum, F. acuminatum, F. sporotrichioides, and F. tricinctum. The soil tillage method and crop rotation did not influence the total incidence of Fusarium spp., but the abundance of a particular species differed depending on agronomic practice. The research suggests that continuous wheat sowing under conditions of reduced soil tillage can increase the level of risk of grain infection with F. graminearum and, consequently, the accumulation of mycotoxins.

Abstract. Maize is becoming more and more important crop for dairy farming as forage and as substrate for biogas production. The mycotoxin producing fungi can spoil feed, reduce cattle productivity and cause health problems. The aim of this research was to study the mycoflora of maize grains in order to clarify the fungal composition and verify the presence of potential mycotoxin producing fungi. The grain samples were collected from different maize hybrid performance trial in Research and Study farm "Vecauce" of Latvia University of Agriculture in 2014. The fungi from 14 genera were isolated from surface sterilized grains. The most abundant were Alternaria, Fusarium and Penicillium spp. Mycotoxin producing fungi are present in maize grain mycoflora, and there is a risk that maize production can contain mycotoxins.

Faba bean (Vicia faba L.) is gaining importance as a crop in northern Europe. In this region, the most important disease of faba bean is chocolate spot disease, attributed to the pathogen Botrytis fabae. However, other Botrytis species have been found to contribute to the disease. Hence, it was decided to isolate fungi from faba bean plants showing symptoms of chocolate spot disease in Latvia, identify the Botrytis species using the DNA sequences of three definitive genes, evaluate the morphological diversity of the isolates in vitro and, finally, to determine the pathogenicity of the isolates in a detached-leaf test. In addition to B. fabae, B. cinerea, B. pseudocinerea and B. fabiopsis were all identified. Phylogenetic analysis of the DNA sequences put all the obtained 44 isolates unequivocally into clusters with known examples of each species. Every species showed wide diversity in its in vitro colour, texture and growing pattern of mycelium, production of sclerotia and pigmentation of the growing medium with much overlap between species showing that this method is not adequate for species discrimination. B. fabae produced the largest lesions on infected leaves, followed closely by B. pseudocinerea and B. cinerea, while B. fabiopsis produced much smaller lesions. The results show that chocolate spot disease of faba bean is attributable to Botrytis four species in northern Europe. This knowledge needs to be considered when controlling the disease by genetic or agronomic means.

Fungi of genus Botrytis are important pathogens of legumes, causing gray mold and chocolate spot diseases. The use of molecular methods to identify pathogens has resulted in the discovery of several new Botrytis species and new associations of pathogens with diseases. Thus, chocolate spot of faba bean is now associated with at least four species: B. fabae, B. cinerea, B. pseudocinerea and B. fabiopsis. Species of Botrytis differ in host plant, pathogenicity, fungicide resistance and other relevant properties that affect disease control. The aim of this study was to identify the species of Botrytis isolated from different legume crops and to evaluate their in vitro pathogenicity. Between 2014 and 2019, 278 isolates of Botrytis were obtained from infected legumes in Latvia. A phylogenetic analysis was carried out by sequencing three nuclear genes, RPB2, HSP60, and G3PDH, considered to be diagnostic for species in this genus. A set of 21 representative isolates was selected for pathogenicity tests on detached leaves of faba bean, field pea, lupin and soybean using 5-mm mycelium-agar plugs. The diameter of the formed lesions under the inoculated plug was measured crosswise each day. The datasets were subjected to analysis of variance with the split-plot design of the experiment and repeated-measures model. Six species were identified: B. cinerea, B. fabae, B. pseudocinerea, B. fabiopsis, B. euroamericana and B. medusae. In addition to the expected combinations of host and pathogen, naturally occurring infections of B. fabiopsis were found on chickpea, B. euroamericana on faba bean and B. medusae in lupin seeds. Species and isolate had significant effects on pathogenicity on all crops tested. Several isolates were pathogenic on two or more host species: two of B. pseudocinerea, two of B. cinerea, two of B. fabiopsis and the one of B. medusae. One isolate of B. pseudocinerea and two of B. fabiopsis caused primary lesions on all five host species. The results show that these Botrytis species have a broad host range that should be borne in mind when planning crop sequences and rotations.

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