The effect of pesticide contamination of the littoral zone on the population of bacteria and fungi was analyzed using the example of a eutrophic water reservoir exposed for >30 years to the influence of expired crop-protection chemicals, mainly DDT. For three consecutive years, quantity analyses of bacteria and fungi were conducted and the composition of the microorganism population analyzed against seasonal dynamics. Mold and yeast-like fungi were also isolated and identified. Within the Bacteria domain, in addition to the large groups of microorganisms (Alphaprotobacteria, Betaprobacteria, and Gammaproteobacteria, Actinobacteria, and Cytophaga-Flavobacterium), the analysis also involved the presence of bacteria predisposed to degraded pesticides in natural environments: Pseudomonas spp. and Alcaligenes spp. The quantity dynamics of aquatic microorganisms indicated that bacteria and fungi under the influence of long-term exposure to DDT can adapt to the presence of this pesticide in water. No modifying effect of DDT was observed on the quantity of microorganisms or the pattern of seasonal relationships in the eutrophic lake. Changes were shown in the percentage share of large groups of bacteria in the community of microorganisms as was an effect of contamination on the species diversity of fungi. The data show the effectiveness of aquatic microorganism–community analyses as a tool for indicating changes in the water environment caused by pesticide contamination.

The study aimed to compare the yeast species diversity in the specific environment of dishwashers, taking into account the potential risk for users. Yeasts were isolated from ten dishwashers and from tap water supplied to the appliances. Samples were collected for mycological analyses at the beginning of each month, from February to May 2016. Four dishwasher sites (rubber seals, detergent dispensers, sprinklers, and water drains) were analyzed. The microfungi were identified by the standard procedures applied in mycological diagnostics. To confirm species identification, molecular analysis was performed based on the sequences of the D1/D2 region. The presence of microfungi was detected in 70% of the investigated appliances. Rubber seals, detergent dispensers, and water drains were the most frequently colonized elements. Thirty-five yeast strains were isolated in this study, of which twenty-seven were obtained from dishwashers and eight from tap water. The strains belonged to six genera and six species (Candida parapsilosis, Clavispora lusitaniae, Dipodascus capitatus, Exophiala dermatitidis, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa). Most of the strains came from rubber seals. In this way, it was demonstrated that the dishwashers’ condition is sufficient as an ecological niche for microfungi.

The study is part of hydromycological investigations of man-affected water bodies in Olsztyn. Our results show that yeast-like fungi are permanent components in three selected lakes (lakes Tursko, Długie and Skanda). Their abundance and species composition depend on the trophic state of each lake.

Fungi of the genus Ampelomyces are the major antagonists of Erysiphales fungi being a significant group of phytopathogens. The hyperparasites attack various developmental stages of powdery mildews. As a result the infested ascomata do not reach the stage of maturity, do not form appendages nor ascospores, which is linked with a reduction of the source of primary infections. Studies conducted so far have mainly been devoted to Ampelomyces fungi application in the biological control of powdery mildews on crops, whilst a few only have been focused on the ecology of these mycoparasites on Erysiphales fungi infecting plants, especially in the urban environment. The present study addresses the natural occurrence and effect of Ampelomyces fungi on the development of ascomata of powdery mildews species. The material was collected in 2005–2009 in several cities of the northeastern Poland. First time ever Ampelomyces spores are reported in mature ascomata of Erysiphales with fully developed appendages. This phenomenon has been observed in the case of two species, viz.: Erysiphe flexuosa on Aesculus spp. and E. vanbruntiana var. sambuci-racemosae on Sambucus racemosa and is presumably linked with improved implementation, propagation and probably better survival during winter months.