Species of the genus Ampelomyces Ces. ex Schltdl. are wide-spread hyperparasites found on more than 65 Erysiphales species [1]. Their hyphae penetrate the vegetative mycelium as well as conidiophores and conidia of the host fungus, thus forming inside them the spore-forming structures, i.e. pycnidia [2]. Hyperparasites may also colonize ascogonia and antheridia as well as young, immature chasmothecia of powdery mildews, transforming them into their own reproductive structures. Infested ascomata do not reach the stage of maturity, do not form appendages nor ascospores, which is linked with the reduction of the source of primary infections [3][4][5][6][7].The capability of hyperparasites to infest different Erysiphales species, to suppress their sporulation as well as to inhibit the formation and development of chasmothecia has contributed to the advance of research addressing mainly the aspect of the application of Ampelomyces fungi in the biological control of powdery mildews [1,[8][9][10][11]. From the economic point of view, Erysiphales species constitute a significant group of phytopathogens of multiple fruit plants and crops. Of high interest to researchers world-wide is also the problem of the genetic diversity of fungi of the genus Ampelomyces, which is still little known and requires in-depth examinations [12][13][14][15][16].World and Polish literature provides a lot of information about presence Ampelomyces fungi on different Erysiphales species in natural condition ([11,17-24]. Relatively few investigations were focused on the ecology of these hyperparasites and their natural occurrence on various Erysiphales species under urban condition [25][26][27]. Therefore, the Department of Mycology of University of Warmia and Mazury in Olsztyn began studies on the occurrence of fungi from the genus Ampelomyces and their impact on the development Erysiphales in urban environment [28][29][30]. Data is also lacking on the effect of Ampelomyces fungi on the development of fruiting bodies of different species of powdery mildews infecting non-farming plants [29]. Works addressing this issue are devoted almost exclusively to a dangerous pathogen of grapevine -Erysiphe necator (Uncinula necator) - [3,5,6,31].An analysis of the colonization of Erysiphales ascomata by Ampelomyces as well as the effect of mycoparasites on their development seems to be crucial in understanding the role of such antagonists in the natural dynamics of a powdery mildew population in its natural environment.The objective of the study was to evaluate the occurrence of fungi of the genus Ampelomyces and their effect on the development of ascomata of species of powdery mildews in the urban environment.
AbstractFungi 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 ...