The effect of fungicidal treatment on selected quality parameters of barley and malt.

Protection of barley grain against contamination by fungi such as Fusarium spp., particularly by those producing mycotoxins, secondary metabolites with adverse health effects, is of principal importance. Fungicides applied immediately after full heading of spring barley is one method of direct protection. In this work, extensive two-year field experiments combined with a detailed chemical laboratory analysis (barley and malt) were performed with the aim to study the effect of previous crops, different fungicides, and other conditions on the selected barley and malt quality parameters (content of beta-glucans, pentosans, oxalic acid, deoxynivalenol, and gushing), while the main task was to follow the effect of the fungicide (used as a treatment to protect against pathogens, mostly Fusarium) on changes of the chemical composition in barley and malt, and gushing. It was found that the relationship between the studied factors and the parameters usually applied to the evaluation of barley and malt quality is quite complex and not straightforward. The responses show typical features of a multifactorial influence with both positive and negative correlations resulting in a decrease or increase in grain quality (concentrations of beta-glucans, pentosans, deoxynivalenol, and other studied parameters). The role of previous crops was also found to be important. The fungicides should be applied at the time of heading but not at the very beginning of this period.

Mites as selective fungal carriers in stored grain habitats.

Mites are well documented as vectors of micromycetes in stored products. Since their vectoring capacity is low due to their small size, they can be serious vectors only where there is selective transfer of a high load of specific fungal species. Therefore the aim of our work was to find out whether the transfer of fungi is selective. Four kinds of stored seeds (wheat, poppy, lettuce, mustard) infested by storage mites were subjected to mycological analysis. We compared the spectrum of micromycete species isolated from different species of mites (Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, Caloglyphus rhizoglyphoides and Cheyletus malaccensis) and various kinds of stored seeds. Fungi were separately isolated from (a) the surface of mites, (b) the mites' digestive tract (= faeces), and (c) stored seeds and were then cultivated and determined. The fungal transport via mites is selective. This conclusion is supported by (i) lower numbers of isolated fungal species from mites than from seeds; (ii) lower Shannon-Weaver diversity index in the fungal communities isolated from mites than from seeds; (iii) significant effect of mites/seeds as environmental variables on fungal presence in a redundancy analysis (RDA); (iv) differences in composition of isolated fungi between mite species shown by RDA. The results of our work support the hypothesis that mite-fungal interactions are dependent on mite species. The fungi attractive to mites seem to be dispersed more than others. The selectivity of fungal transport via mites enhances their pest importance.