Random amplified polymorphic DNA (RAPD) markers were used to estimate genetic relationship and diversity of Fusarium species associated with pink ear rot of maize. Three Fusarium species – F. verticillioides, F. temperatum and F. subglutinans sensu stricto were collected from contaminated corn kernels. A collection of 41 randomly selected Fusarium isolates (16 F. verticillioides, 16 F. temperatum and nine F. subglutinans sensu stricto) was screened for polymorphism with thirty decamer primers. Seventeen primers that had generated a high number of polymorphic loci were used for the analysis of genetic diversity. The primers yielded a total of 146 polymorphic loci, an average of 8.59 polymorphic bands per primer. The percentage of polymorphic bands (%P) was 46.1%. The RAPD-based UPGMA analysis demonstrated that although F. temperatum and F. subglutinans s.s. form two distinct groups they are more similar to each other than to F. verticillioides. Fusarium verticillioides was the most heterogenous species (Nei’s genetic diversity 0.180), while the least heterogenous one was F. subglutinans s.s. whose genetic diversity was 0.098. The analysis of the translation elongation factor 1-α and β-tubulin gene sequences as well as the mating type ratio were employed to support the RAPD data.

Key message Comprehensive management of urban greenery is a key approach to control fungal diseases of trees and shrubs to avoid the deterioration in their health status. Abstract Preliminary investigations on the health status related to fungal diseases of trees and shrubs growing in four green squares in Warsaw were conducted in 2017–2019. The examined plants were affected by diseases that are commonly identified in urban greenery, e.g., powdery mildew (causal agents: Sawadaea tulasnei, S. bicornis, Podosphaera leucotricha, Podosphaera sp., Erysiphe alphitoides, E. magnifica, E. berberidis, E. flexuosa and E. adunca), rusts (Gymnosporangium sabinae, Melampsora laricis-populina), apple scab (Venturia inaequalis), tar spot of maple (Rhytisma acerinum), and oyster mushroom (Pleurotus ostreatus). The causal agents of the diseases were identified based on their morphological (macro- and microscopic) features. Preventing and managing fungal plant diseases and reduction of their effects are the key tasks in conscious management of urban greenery. To address this issue, the study presents basic guidelines based on the application of various recommended actions and good practices, which constitute a comprehensive and sustainable strategy for integrated protection of trees and shrubs against these diseases. The implementation of the strategy for complex management of urban greenery is a crucial measure aimed at maintenance of a high health status of urban plants.

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv. syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. syringae.

Phlebiopsis gigantea (Fr.) Jülich has been successfully used as a biological control fungus for Heterobasidion annosum (Fr.) Bref., an important pathogen of pine and spruce trees. The P. gigantea species has been known for many years, but our understanding of the relationship between various isolates of this fungus has been substantially improved through the application of DNA sequence comparisons. In this study, relationships between P. gigantea and selected Basidiomycota species was determined, based on elongation factor 1-alpha (EF1α) partial DNA sequence and in silico data. A total of 12 isolates, representing the most representatives of P. gigantea, with diverse geographic distributions and hosts, were included in this study. Phylogenetic trees generated for sequences obtained in this research, grouped the European taxa of P. gigantea and partial sequence of the genome deposed in NCBI database, in a strongly supported clade, basal to the rest of the strains included in the study. P. gigantea isolates originating from Poland, Finland, Sweden, Great Britain and partial sequence of genome formed a monophyletic group. Within this group, isolates of P. gigantea constituted two subclades, showing their partial difference like the two SNPs (single nucleotide polymorphisms) between one and the rest of isolates. The intron and exon relationships among P. gigantea isolates were moreover resolved. The results obtained using the EF1α region should be useful in the selection of more efficient P. gigantea isolates for limiting forest tree root pathogens.

S u m m a r yThe aim of the work was to study the development of pseudothecia of M. graminicola. The experiment was carried out in 2002/2003. Wheat leaves collected at Koñczewice (near Toruñ), S³upia Wielka (near Poznañ) and Kromìøí• (Czech Republic) were kept on an experimental field in Warsaw. The pseudothecia were observed under the light and transmission electron microscopy.The first pseudothecia were observed on the dead leaves at the end of July. The largest number of fruiting bodies were noted in October.During the whole period of observation fruiting bodies contained asci in several stages of development. Most of them were immature. In spring the pseudothecia were not found.