MYCOFLORA OF STRAWBERRY PLANTS

Goal. To identify fungi associated with the tissues of strawberry plants and evaluate the frequency of their isolation at different stages of plant growth. 
Methods. The research was conducted in the Right Bank Forest Steppe of Ukraine (Cherkasy Region) in 2021—2023, cv. ‘Clery’. Plant samples were taken in the phases of rosette formation (April), budding-flowering (May), fruit ripening (June) and in the post-harvest period (July-August). The analysis was carried out in laboratory conditions using macroscopic and biological methods. 
Results. During the research period, fungi belonging to 27 genera were isolated from strawberry tissues. In general, they can be divided into three groups: pathogens of leaves, which is the most numerous, berries, roots and crown. Representatives of the genera Alternaria, which were isolated from 57—100% of samples, and Fusarium (40—88%) occurred most often. Less often, but also during the entire growing season, Penicillium spp. (36—69%), Podosphaera aphanis (11—80%), Botrytis cinerea (27—67%), Paraphomopsis obscurans (24—77%) were isolated. Among the leaf diseases powdery mildew was recorded during all growing season, with a maximum in the fruit ripening phase. White leaf spot was observed starting from the budding-flowering phase, and leaf scorch was found from the fruit ripening phase. Gray rot was the most common fruit disease. The root system was more often affected by Fusarium spp. 
Conclusions. The obtained results demonstrate that during the entire growing season fungi of the genera Alternaria, Fusarium, Penicillium, as well as Podosphaera aphanis, Botrytis cinerea and Paraphomopsis obscurans were most often isolated from strawberry tissues. R.grevilleana was isolated starting from the budding-flowering phase, and D. earlianum from the fruit ripening phase. Species from the genera Podosphaera, Ramularia, Diplocarpon, Colletotrichum, Pestalotiopsis, Verticillium, Sclerotinia, Gnomoniopsis, Rhizoctonia, Coniella, Rhizopus, Septoria, Cylindrocarpon require constant control of their spread. Under favorable conditions for their development, they can cause damage to plants and a significant lack of harvest. The seasonal monitoring of fungi on strawberry provides a means for establishing the optimal periods for their control and developing effective disease protection system.

ments (potassium, phosphorus, calcium, sodium, magnesium, iron, iodine).Berries are consumed fresh and processed.The yield and quality depend on the place where strawberries are grown, the weather conditions of the year, the cultivar, the special cultural practices.
In Ukraine, root rot, leaf scorch, white spot, powdery mildew, verticillium wilt and gray rot are considered the main diseases of strawberries [6,7,9,10,11].At the same time, when studying pathogens of strawberry diseases, the main atten-tion was focused on their harmfulness, plant resistance, and the impact of protective measures.Little attention was paid to the processes of formation of mycoflora complexes on strawberry.A wider study of this issue will be important for the improvement of protective measures, may become the basis for their rational selection and increase the effectiveness of their appli cation.
The goal of the research was to identify fungi associated with the tissues of strawberry plants and to estimate the frequency of their isolation in different periods of the growing season.
Methods of investigation.Surveys of fruit-bearing strawberry crops were carried out under conditions of the Right Bank Forest Steppe of Ukraine (Cherkasy Region) in 2021-2023 on the cv.'Clary'.Plant samples were taken in the phases of rosette formation (April), budding-flowering (May), fruit ripening (June) and in the post-harvest period (July-August).Samples were labeled and delivered in paper bags to the laboratory, where they were analyzed using macroscopic and biological methods.At the first stage, microscopic methods were used to detect the sporulation of fungi.In order to stimulate mycelial growth and improve sporulation, a moist chamber and nutrient medium were used.The tissue segments were washed with tap water, sterilized with 96% ethanol and washed twice with sterile water.Then they were placed in a humid chamber and in Petri dishes with potato-glucose agar (PDA) and kept at temperature 24°C.Pathogens were identified by cultural and morphological characteristics of colonies and morphometrics of sporulation [12].
The frequency of isolation (IF, %) was calculated according to the formula: where m is the number of samples from which this genus or species was isolated; M is the total number of samples.
Results and discussion.Du ring the research period, fungi belonging to 27 genera were isolated from strawberry tissues (Table 1).Alternaria spp.are known as pathogens of strawberry leaf spot, which is considered an economically significant disease.It was found in many Asian countries and in Europe [13,14].In addition, fungi of this genus can occur as a secondary infection, i.e. they colonize tissues damaged by hail, pests, or have other physical or biological injuries [15].They are also included in the complex of pathogens that cause mold and rotting of berries during the fruiting period of strawberries [13].
Fusarium spp.can cause significant damage to strawberry plants.The complex of fungi of this genus (Fusarium oxysporum Schlecht., F. commune K. Skovg., F. equiseti  Botrytis cinerea (Fig. 1) causes gray mold -a commercially harmful disease of strawberries.This pathogen infects fruits in the field, during storage, and transportation [16].The fungus can develop as a parasite and as a saprophyte [7].

The frequency of isolation of fungi during the growing season (Cherkasy region, cv. 'Clery', average for 2021-2023), %
Fruit rot can also be caused by Rhizopus spp.and Mucor spp.In the field, symptoms appear on mature or nearly mature fruits.At the same time, damage to the fruit surface is necessary for infection.The process develops very intensively, the mycelium of the fungus can completely cover the fruit in almost a day.Pathogens can continue to grow on harvested infected but still asymptomatic berries, as well as on healthy fruits that have been exposed to spores, causing fruit losses during processing and storage [7,15,17].
Penicillium fruit rot (mostly Penicillium expansum Link and some other species of this genus), can also cause significant post-harvest losses [17].However, endophytic Penicillium spp.have a wide spectrum of antimicrobial activity.Investigations of Zargar et al [18] showed that P. hordei Stolk and P. polonicum K.W. Zaleski isolated from the leaves and shoots of strawberries have antagonistic properties against the causative agent of anthracnose.
Powdery milde w (Podosphaera aphanis) was the first to appear among strawberry leaf diseases.Its symptoms were recorded starting from the phase of rosette formation with an average isolation frequency of 11% over the years of research.Over time, the damage by the disease increased and reached a maximum during the ripening period of the fruits.
The pathogens of the most common strawberry leaf spots -white spot (R. grevilleana) and leaf scorch (D. earlianum) (Fig. 2) were found mainly in the second half of the growing season.The frequency of their isolation reached 93.3 and 76.7%, respectively.
It is necessary to pay attention to the rather high frequency of detection of the fungi Paraphomopsis ob-scurans and Pestalotiopsis sp.Fungi of the genus Pestalotiopsis (Fig. 3) can cause necrotic spots on leaves and flowers, as well as affect fruits [19,20].There are also reports that they are pathogens of root and collar rot [21,22].
Black spot can appear on leaves, stems, shoots, fruits and collar of Gnomoniopsis comari (Fig. 4) transfers with planting material and appears mainly at the beginning of the season.It can exist as a systemic infection in shoots that does not become apparent until favorable conditions occur and the fungus begins to infect leaves and calyxes [28].
Rhizoctonia sp. (Fig. 5) was isolated from strawberry roots in the post-harvest period.This fungus is considered as one of the main pathogens of strawberry root rot and is often found in combination with other pathogens, in particular Fusarium spp.[15,28].

CONCLUSIONS
The obtained results demonstrate that during the entire growing season fungi of the genera Alternaria, Fusarium, Penicillium, as well as Podosphaera aphanis, Botrytis cinerea and Paraphomopsis obscurans were most often isolated from strawberry tissues.R.grevilleana was isolated starting from the budding-flowering phase, and D.earlianum -from the fruit ripening phase.
Monitoring of strawberry mycoflora during the growing season provides an opportunity to establish optimal periods for disease control and the development of effective protection systems.
Funding.The research was carried out as part of the project 24.01.02.08.P «Research of the main diseases of fungal etiology of strawberries and measures to limit their development.»Conflict of interest.The authors declare no conflict of interest.