Diversity of fungi colonizing and damaging leaves of pontic azalea Azalea pontica MARIA KOWALIK Department of Plant Protection, University of Agriculture in Kraków 29 Listopada 54, PL-31-425 Kraków, m.kowalik@ogr.ur.krakow.pl Kowalik M.: Diversity of fungi colonizing and damaging leaves of pontic azalea Azalea pontica. Acta Mycol. 48 (2): 227–236, 2013. The research aimed at verification of fungi species colonizing phyllosphere of pontic azalea Azalea pontica L. and at comparison of the fungi species composition: – in the natural stand in the Kołacznia nature reserve, – in arboretum collections at Bolestraszyce and Rogów. 600 fragments of healthy, infected and fallen leaves of pontic azalea were collected for mycological analyses. The species forming the largest number of colonies identified from the healthy leaves were: A. alternata, Ph. cyclaminis, E. nigrum, Ph. medicaginis and B. cinerea, from infected leaves: A. alternata, E. nigrum, Ph. cyclaminis, S. fimicola, T. viride and A. phaeospermum, whereas: E. nigrum, A. alternata, S. fimicola, Ph. cyclaminis and B. cinerea were isolated from the fallen leaves, which indicates that a majority of fungi persistently colonize the leaves during vegetation period and damage them, which leads to defoliation. Colonization of pontic azalea phyllosphere in arboreta by more numerous fungi colonies and species than under conditions of natural sites evidences their increased pressure in the arboreta environment. Key words: pontic azalea, arboretum, reserve, health status, leaves INTRODUCTION Pontic azalea Azalea pontica L., i.e. yellow rhododendron [Rhododendron luteum Sweet, syn. R. flavum G. Don (Anioł-Kwiatkowska 2003)] is a critically endangered species included in The Polish Red Book of Plants (Kaźmierczakowa, Zarzycki 2001). Its only natural stand in Poland is located in the Kołacznia nature reserve at Wola Zarzycka near Leżajsk. The seeds collected on the natural site were used to cultivate the specimens which are growing in the collection of Arboretum and Department of Physiography in Bolestraszyce and in the Arboretum of the War- saw University of Life Sciences (SGGW) in Rogów (Piórecki, Dubiel 2009; Piórecki, Zarzycki 2010). ACTA MYCOLOGICA Vol. 48 (2): 227–236 2013 DOI: 10.5586/am.2013.024 Dedicated to Professor Maria Ławrynowicz on the occasion of the 45th anniversary of her scientific activity 228 M. Kowalik Health status of azalea shrubs is affected by cultivation conditions resulting from the specific site requirements and disease agents. Identification of the organisms colonizing phyllosphere of pontic azalea, including pathogens causing health distur- bances, is a comparative study comprising plants under conditions of natural sites and in arboreta. Identification of the population and species diversity of fungi in pontic azalea phyllosphere makes possible following the results of colonization and damaging of leaves. The aim of the research was verification of fungi species colonizing the phyllo- sphere of Azalea pontica and comparison of fungi species composition on the natural site and in the arboreta. MATERIALS AND METHODS Observations of the of pontic azalea health status were conducted in the third dec- ade of May, July, August and September 2011 on a site in the Kołacznia nature reserve, on the collection of the Arboretum in Bolestraszyce (SE Poland) and on the collection of Arboretum in Rogów (Central Poland). On each date 10 healthy leaves (green, without obvious disease symptoms), infected leaves (showing necrotic symp- toms) and fallen leaves were collected from the three sites. A total of 1800 leaf frag- ments were collected for mycological analyses. The leaf fragments were disinfected in 70% ethanol. Isolation and cultivation of mycobiota were conducted according to standard methods applied in mycology (Kowalik 2008). For taxonomic identification of the mycobiota the following keys were used: Guba (1961); Domsch et al. (1980); Sutton (1980); Ellis, Ellis (1987) and Rifai (1987). The basis of classification was the system of Kirk et al. (2008) and the authors’ epithets by fungal species names were verified according to Index Fungorum (2012). On the basis of fungi specification considering the share of individual species in the total fungi community, they were classified to the group of dominants (constitut- ing >5% of the entire community), influents (1-5%) and accessory fungi (<1%). Similarity coefficient (Sőrensen index) was calculated for the analysed sites, com- prising the number of fungi species (Kowalik 1993). RESULTS Altogether 2120 fungi colonies belonging to 64 species were isolated from the plant material: healthy, infected and fallen leaves of Azalea pontica collected on the natural site in the Kołacznia nature reserve, on the collection of the Arboretum in Bolestraszyce and on the collection of Arboretum in Rogów. There were 568 colonies comprising 39 species isolated from healthy green leaves (Tab. 1), 657 colonies and 40 species from infected leaves (with necrotic symptoms) (Tab. 2) and 895 colonies and 52 species from fallen leaves (Tab. 3). The largest number of fungi colonies and species existed on healthy azalea leaves in the Kołacznia nature reserve, whereas the least number in the arboretum in Bolestraszyce. These leaves were in the first place colonized by: Alternaria alternata, Diversity of fungi colonizing and damaging leaves of pontic azalea 229 Phialophora cyclaminis, Epicoccum nigrum, Phoma medicaginis and Botrytis cinerea. These fungi were classified to the dominant group. Cladosporium sphaerospermum, Trichoderma viride, Pestalotiopsis sydowiana, Isaria fumorosea, Mortierella alpina, M. parvispora, Khuskia oryzae, Trichoderma koningii, Sordaria fimicola, Mammaria echi- nobotryoides, Penicillim expansum, P. waksmanii, Truncatella truncata and other were classified to the influent group, whereas the other 10 species were identified as ac- cessory fungi (Tab. 1). Table 1 Fungi colonizing healthy leaves of pontic azalea Azalea pontica Fungus K oł ac zn ia re se rv e B ol es tr as zy ce ar bo re tu m R og ów ar bo re tu m To ta l Pe rc en ta ge [% ] Alternaria alternata (Fr.) Keissl. 8 28 23 59 10.39 Apiospora montagnei Sacc. 12 12 2.11 Arthrinium euphorbiae M.B. Ellis 9 9 1.58 Arthrinium phaeospermum (Corda) M.B. Ellis 3 3 0.53 Aspergillus versicolor (Vuill.) Tirab. 1 1 0.18 Aureobasidium pullulans (de Bary) G. Arnaud 1 7 8 1.41 Botrytis cinerea Pers 31 1 32 5.63 Chaetomim globosum Kunze 2 2 0.35 Cladosporium cladosporioides (Fresen.) G.A. de Vries 1 1 9 11 1.94 Cladosporium herbarum (Pers.) Link 5 4 9 1.58 Cladosporium sphaerospermum Penz. 8 5 11 24 4.23 Coleophoma rhododendri Syd. 1 1 0.18 Davidiella macrocarpa Crous, K. Schub. & U. Braun 9 3 12 2.11 Epicoccum nigrum Link 6 27 11 44 7.75 Giberella pulicaris (Fr.) Sacc. 2 2 0.35 Ilionectria radicicola (Gerlach & L. Nilson) P. Chaverri & Salgado 1 1 0.18 Isaria fumorosea Wize 3 7 12 22 3.87 Khuskia oryzae H.J. Hadson 7 12 19 3.34 Mammaria echinobotryoides Ces. 14 14 2.46 Mortierella alpina Peyronel 14 6 20 3.52 Mortierella parvispora Linnem. 14 7 21 3.70 Mucor hiemalis f. hiemalis Wehmer 1 1 2 0.35 Parahoma chrysanthemicola (Hollós) Gruyter, Aveskamp & Verkley 1 1 2 0.35 Penicillium expansum Link 13 13 2.29 Penicillium waksmanii K.M. Zalessky 5 8 13 2.29 Pestalotiopsis sydowiana (Bres.) B. Sutton 20 3 23 4.05 Phialophora cyclaminis J.F.H. Beyma 35 13 1 49 8.63 Phoma eupyrena Sacc. 2 4 6 1.06 Phoma exigua (Desm.) Gruyter, Aveskamp & Verkley 1 1 2 0.35 Phoma medicaginis Malbr. & Roum. 11 26 37 6.51 Sordaria fimicola (Roberge ex Desm.) Ces. & De Not 11 11 1.94 Thanatephorus cucumeris (A.B.Frank) Donk 3 3 0.53 Trichoderma koningii Oudem. 17 17 2.99 Trichoderma pseudokoningii Rifai 11 11 1.94 Trichoderma viride Pers. 9 4 14 27 4.75 Truncatella truncata (Lev.) Steyaert 4 8 12 2.11 Umbelopsis isabellina (Oudem.) W. Gams 9 9 1.58 Umbelopsis ramanniana (Möller) W. Gams 2 2 0.35 Umbelopsis vinacea (Dixon-Stew.) Arx 2 1 3 0.53 Total 206 174 188 568 100.00 230 M. Kowalik Table 2 Fungi colonizing infected leaves of pontic azalea Azalea pontica Fungus K oł ac zn ia re se rv e B ol es tr as zy ce ar bo re tu m R og ów ar bo re tu m To ta l Pe rc en ta ge [% ] Alternaria alternata (Fr.) Keissl. 21 85 56 162 24.65 Arthrinium euphorbiae M.B. Ellis 2 2 0.30 Arthrinium phaeospermum (Corda) M.B. Ellis 16 11 7 34 5.17 Arthrinium sphaerospermum Fuckel 2 2 0.30 Aureobasidium pullulans (de Bary) G. Arnaud 1 3 4 0.60 Botrytis cinerea Pers. 11 7 18 2.74 Chaetomim globosum Kunze 2 12 14 2.13 Cladosporium cladosporioides (Fresen) G.A. de Vries 2 8 3 13 1.98 Cladosporium herbarum (Pers.) Link 4 6 10 1.52 Cladosporium sphaerospermum Penz. 1 15 8 24 3.65 Davidiella macrocarpa Crous, K. Schub. & U. Baun 2 2 0.30 Epicoccum nigrum Link 14 32 47 93 14.16 Fusarium culmorum (W.G. Sm.) Sacc. 2 1 3 0.46 Fusarium oxysporum Schltdl. 2 3 5 0.77 Fusarium poae (Peck) Wollenw. 4 4 0.60 Giberella pulicaris (Fr.) Sacc. 7 7 1.07 Ilionectria radicicola (Gerlach & L. Nilson) P. Chaverri & Salgado 4 4 0.60 Khuskia oryzae H.J. Hads. 2 2 0.30 Mammaria echinobotryoides Ces. 6 1 7 1.07 Mortierella alpina Peyronel 6 7 13 1.98 Mortierella parvispora Linnem. 7 3 10 1.52 Mucor hiemalis f. hiemalis Wehmer 1 1 0.15 Paraconiothyrium minitans (W.A. Campb.) Verkley 4 4 0.60 Paraphoma chrysanthemicola (Hollós) Gruyter, Aveskamp & Verkley 3 3 0.46 Paraphoma fimeti (Brunaud) Gruyter, Aveskamp & Verkley 5 5 0.77 Penicillium expansum Link 1 1 0.15 Penicillium waksmanii K.M. Zalessky 9 7 16 2.44 Pestalotiopsis sydowiana (Bres) B. Sutton 17 17 2.59 Phialophora cyclaminis J.F.H. Beyma 16 18 16 50 7.61 Phoma exigua (Desm.) Aveskamp, Gruyter & Verkley 1 4 5 0.77 Phoma medicaginis Malbr. & Roum. 7 7 1.07 Phoma putaminum Speg. 4 4 0.60 Pleurostomophora richardsiae (Nannf.) L. Mostert, W. Gams & Crous 1 4 5 0.77 Rhizopus stolonifer (Ehrenb.) Vuill. 6 6 0.92 Sordaria fimicola (Roberge ex Desm.) Ces & De Not 23 8 11 42 6.40 Talaromyces wortmannii C.R. Benj. 2 2 0.30 Thanatephorus cucumeris (A.B. Frank) Donk 7 7 1.07 Trichoderma viride Pers. 29 4 2 35 5.33 Umbelopsis isabellina (Oudem.) W. Gams 1 8 1 10 1.52 Umbelopsis ramanniana (Möller) W. Gams 4 4 0.60 Total 184 237 236 657 100.00 Diversity of fungi colonizing and damaging leaves of pontic azalea 231 Table 3 Fungi colonizing fallen leaves of pontic azalea Azalea pontica Fungus K oł ac zn ia re se rv e B ol es tr as zy ce ar bo re tu m R og ów ar bo re tu m To ta l Pe rc en ta ge [% ] Actinomucor elegans (Eidam) C.R. Benj. et Hesselt 3 3 0.34 Alternaria alternata (Fr.) Keissl. 21 47 51 119 13.29 Apiospora montagnei Sacc. 2 2 0.22 Arthrinium euphorbiae M.B. Ellis 1 1 0.11 Arthrinium phaeospermum (Corda) M.B. Ellis 1 1 0.11 Arthrinium sphaerospermum Fuckel 1 1 0.11 Aspergillus ustus (Bainier) Thom et Church 2 2 0.22 Botrytis cinerea Pers. 32 28 60 6.70 Cadophora malorum (Kidd et Beaumont) W. Gams 5 5 0.56 Calonectria morganii Crous, Alfenas & M.J. Wingf. 1 1 2 0.22 Chaetomim globosum Kunze 6 6 0.67 Cladosporium cladosporioides (Fresen.) G.A. de Vries 2 4 3 9 1.01 Cladosporium sphaerospermum Penz. 7 7 0.78 Epicoccum nigrum Link 72 72 67 211 23.57 Fusarium culmorum (W.G. Sm.) Sacc. 2 3 5 0.56 Fusarium flocciferum Corda 2 2 0.22 Fusarium oxysporum Schltdl. 4 4 0.45 Giberella pulicaris (Fr.) Sacc. 2 2 0.22 Giberella tricincta El-Gohll, McRitchie, Schoult. et Ridings 5 5 0.56 Humicola fuscoatra var. fuscoatra Traaen 4 4 0.45 Humicola grisea Traaen 7 3 10 1.12 Ilionectria radicicola (Gerlach & L. Nilson) P. Chaverri & Salgado 2 5 7 0.78 Isaria fumosorosea Wize 2 2 0.22 Mammaria echinobotryoides Ces. 5 5 0.56 Mortierella alpina Peyronel 2 16 18 2.01 Mucor hiemalis f. hiemalis Wehmer 5 7 12 1.34 Oidiodendron griseum Robak 1 1 0.11 Oidiodendron tenuissimum (Peck) S. Huges 1 4 5 0.56 Paraphoma chrysanthemicola (Hollós) Gruyter, Aveskamp, Gruyter & Verkley 1 2 3 0.34 Penicillium citrinum Thom 1 2 3 0.34 Penicillium expansum Link 3 3 0.34 Pestalotiopsis sydowiana (Bres.) B. Sutton 1 7 8 0.89 Phialophora cyclaminis J.F.M. Beyma 42 14 11 67 7.49 Phoma destructiva Plowr. 1 1 0.11 Phoma eupyrena Sacc. 9 9 1.01 Phoma exigua (Desm.) Aveskamp, Gruyter & Verkley 4 28 32 3.58 Phoma herbarum Westend. 11 11 1.23 Phoma medicaginis Malbr. & Roum. 18 16 34 3.80 Phoma putaminum Speg. 1 3 4 0.45 Pleospora azalea (Voglino) Priest 13 13 1.45 Pleurostomophora richardsiae (Nannf.) L. Mostert, W. Gams & Crous 1 1 0.11 Rhizopus stolonifer (Ehrenb.) Vuill. 16 11 27 3.02 Scopulariopsis brumptii Salv.-Duval 6 6 0.67 Scopulariopsis chartarum (G. Sm.) F.J. Morton et G.Sm. 11 11 1.23 Sordaria fimicola (Roberge ex Desm.) Ces. et De Not 30 28 22 80 8.94 Talaromyces wortmannii C.R. Benj. 3 3 0.34 Trichoderma koningii Oudem. 6 6 0.67 Trichoderma pseudokoningii Rifai 2 2 0.22 Trichoderma viride Pers. 9 5 14 1.56 Truncatella truncata (Lév.) Steyaert 3 15 18 2.01 Umbelopsis isabellina (Oudem.) W. Gams 12 5 7 24 2.68 Umbelopsis ramanniana (Möller) W. Gams 4 4 0.45 Total 244 315 336 895 100.00 232 M. Kowalik Infected leaves, showing symptoms of necrosis collected in arboreta were colo- nized by a comparable number of fungi colonies, while leaves in Bolestraszyce and on the natural site in Kołacznia by a similar number of fungi species (Tab. 2). Domi- nant colonies: A. alternata, E. nigrum, Ph. cyclaminis, S. fimicola, T. viride and Ar- thrinium sphaerospermum were isolated from these leaves in a prevailing number. 14 species which were classified to the influents included: C. sphaerospermum, B. cinerea, Chaetomium globosum, P. sydowiana, M. alpina and P. waksmanii. The least numerous fungi colonies and species existed on the fallen leaves gath- ered in the Kołacznia reserve, whereas the largest number was found in the Rogów arboretum (Tab. 3). Epicoccum nigrum, A. alternata, S. fimicola, Ph. cyclaminis i B. cinerea colonies dominated in fungi community isolated from the fallen azalea leaves. In the influent group the most numerous were: Ph. medicaginis, Ph. exigua and Rhizopus stolonifer. A total of 634 colonies comprising 37 species were identified on the leaves in three analyzed sites in the Kołacznia reserve, 726 colonies and 43 species in the Bolestraszyce arboretum and 28 species within 760 colonies in the arboretum in Rogów. Similarity indices between individual sites of pontic azalea sites, computed for the communities of fungi species (Tab. 4), evidence the greatest number of com- mon species (50-56%) occurring on infected and healthy leaves in the arboreta in Bolestraszyce and Rogów. The same high similarity index (over 48%) was computed for infected leaves collected in the Kołacznia reserve and in both arboreta. Fungi communities isolated from fallen leaves differed considerably by their species com- position, the least number of common species (28%) occurred in the fungi commu- nity isolated from leaves in the Kołacznia reserve and Rogów arboretum. DISCUSSION Azalea shrubs growing on natural sites, in collections of arboreta or botanical gar- dens, but also in city green areas or in household gardens are under pressure of vari- ous pathogenic organisms, most frequently fungi and fungus-like organisms (Kita, Mazurek 2003; Kowalik 2008; Kowalik et al. 2012). The importance of phyllosphere, in which a competition exists between pathogens and saprotrophs resulting in dis- eases leading to premature plant defoliation, is emphasized in discussion on plant health status. Table 4 Similarity coefficient for fungi communities isolated from leaves of pontic azalea Azalea pontica on three sites Leaves Similarity coefficient [%] Kołacznia - Bolestraszyce Kołacznia - Rogów Bolestraszyce - Rogów Healthy 39.13 45.83 50.00 Infected 48.88 48.97 56.52 Fallen 44.44 28.57 31.03 Total 47.79 40.79 44.59 Diversity of fungi colonizing and damaging leaves of pontic azalea 233 Generally, fungi species colonizing healthy pontic azalea leaves were sapro- trophs from the genera of Apiospora, Arthrinium, Isaria, Khuskia, Mammaria, Mor- tierella, Trichoderma and Umbellopsis. The share of necrotrophs, such as A. alternata, E. nigrum and S. fimicola in the total fungi community isolated from azalea leaves on the natural site in the Kołacznia reserve was small, whereas S. fimicola did not colonize azalea leaves in the arboreta at all. While comparing fungi communities isolated from pontic azalea leaves and evergreen rhododendron leaves (Kowalik 2009), it was noticed that also numerous saprotrophs from the Acremonium, Asper- gillus, Chaetomium and Humicola genera colonized azalea leaf blades. Asymptomatic colonization of pontic azalea by B. cinerea in the Kołacznia re- serve in May during the vegetation period resulted in the occurrence of grey mould on the bushes with visible symptoms of necrosis on the edges of leaf blades. The number of fungi in the community colonizing healthy laves of azalea growing on the natural site in the Kołacznia reserve was much higher than in the arboreta in Bolestraszyce or Rogów, however, the number of pathogen colonies in this com- munity was low. A similar relationship was described by Kita and Mazurek (2003) who compared azalea health status in the arboretum in Wojsławice and Botanical Garden in Wrocław (SW Poland), however ascribing the effect of polluted air on reduction of pathogenic fungi seems unfounded. Diversified similarity indices for fungi communities isolated from healthy leaves indicate a species diversity of fungi colonizing azalea leaves on natural sites and in arboreta. Alternaria alternata and E. nigrum dominated on infected, necrotic azalea leaves collected in the arboreta in Bolestraszyce and Rogów, which confirms previous re- search results (Kowalik 2009; Kowalik et al. 2011). The same fungi, but also Coe- lophoma empetri, Humicola fuscoatra, H. grisea, P. expansum, Penicillium verrucosum, P. sydowiana, Septoria azalea, S. fimicola, Umbelopsis isabellina, as well as fungi from Cylindrocarpon, Fusarium, Mortierella, Phialophora, Phoma, Trichoderma and other genera were found on necrotic evergreen rhododendron and azalea leaves (Kowalik, Muras 2007; Kowalik 2008; Kowalik et al. 2010a; 2010b; 2012). The results obtained confirm the pathogenicity and aggressiveness of many of these fungi species, previ- ously registered on rhododendron leaves. Leaf damage due to Thanatephorus cuc- umeris, a pathogen only sporadically isolated from rhododendron leaves (Kowalik et al. 2010b) is visible in the presented investigations. High similarity indices for fungi communities isolated from infected leaves indi- cate that necrosis of azalea leaves on three analyzed sites was caused by a group of pathogenic species, including necrotrophs. Numerous investigations (Kita, Mazurek 2003; Kowalik, Muras 2007; Kowalik et al. 2010 a; 2011) documented the presence and role of necrotrophs in the process of causing necrotic blots, dieback and intensi- fied, premature falling of leaves. It was demonstrated that toxic fungus A. alternata played the dominant role. Presented investigations draw attention to a low number of this species on healthy and infected leaves on the natural site in Kołacznia in com- parison with the arboreta in Bolestraszyce and Rogów. This situation may be due to vicinity of other species from Ericaceae family – a reservoir of pathogenic fungi (Kowalik, Sagan 2005; Kowalik, Wandzel 2005). Isolation of almost twice larger number of fungi colonies and species from pre- maturely fallen leaves, in comparison with healthy leaves, evidences an intensified 234 M. Kowalik colonization and damaging of leaf blade by various fungi species. Species, which earlier caused leaf necroses, among others E. nigrum, A. alternata, S. fimicola, Ph. cyclaminis i B. cinerea played the main role. These fungi constituted almost 60% of the identified isolates. Equally big share of A. alternata, E. nigrum, S. fimicola and P. expansum was registered in previous papers by Kowalik et al. (2011, 2012). Presence of fungi from Actinomucor, Mucor, Rhizopus, Trichoderma, Mortierella and Umbel- opsis genera on fallen leaves may be connected with the plant age, represented by senile specimens with rotten, moist shoots. Presence of over a dozen fungi species of between once and thrice frequency is noticeable in the fungi communities isolated from fallen leaves, which may evidence an accidental colonizing of fallen leaves by the species living in soil. Isolation of pathogenic Fusarium, Giberella, Ilionectria, Phoma fungi from infect- ed and fallen pontic azalea leaves was corroborated in the literature of the subject (Kita, Mazurek 2003; Kowalik, Muras 2007; Kowalik 2008; Kowalik et al. 2010a; 2010b; 2011; 2012). A comparison of P. sydowiana (syn. Pestalotia sydowiana) and Truncatella truncata (syn. Pestalotia truncata) in causing necrotic symptoms on the leaves of azalea and evergreen rhododendron leaves (Kowalik 2008, 2009; Kowalik et al. 2010a, 2010b, 2012) revealed that these fungi were more often colonizing healthy leaves of pontic azalea, than infected or fallen leaves. The highest percentage differences between similarity indices for fallen azalea leaves evidence a considerable diversity of mycobiota colonizing this kind of leaves. CONCLUSIONS 1. Fungi communities existing in pontic azalea phyllosphere on the natural site in the Kołacznia nature reserve and on the collection of the Arboretum and Depart- ment of Physiography in Bolestraszyce, as well as on the Warsaw University of Life Sciences (SGGW) Arboretum collection in Rogów differed with the species composition and number of colonies. 2. The species whose colonies were isolated in largest numbers from healthy leaves of pontic azalea comprised: A. alternata, Ph. cyclaminis, E. nigrum, Ph. medicagi- nis and B. cinerea, from infected leaves: A. alternata, E. nigrum, Ph. cyclaminis, S. fimicola, T. viride and A. phaeospermum, and from fallen leaves: E. nigrum, A. alternata, S. fimicola, Ph. cyclaminis and B. cinerea, indicating that majority of them persistently colonized and damage leaves during vegetation period leading to their premature falling. 3. 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Volynian Polesia – main source of the Yellow Azalea (Rhododendron luteum Sweet) in European garden and parks. Rocznik Polskiego Towarzystwa Dendrologicznego 57: 29-32. Piórecki J., Zarzycki K. 2010. Arboretum Bolestraszyce. Przewodnik. Bolestraszyce. Rifai M. A. 1987. A revision of genus Trichoderma. Mycol. Papers 116: 1-56. Sutton B. C. 1980. The Coelomycetes. CMI, Kew, Surrey. 236 M. Kowalik Różnorodność grzybów zasiedlających i uszkadzających liście azalii pontyjskiej Azalea pontica Streszczenie Obserwacje stanu zdrowotnego azalii pontyjskiej Azalea pontica przeprowadzono w 2011 roku na stanowisku naturalnym w rezerwacie Kołacznia, w kolekcji Arboretum i Zakładu Fizjogra- fii w Bolestraszycach oraz w kolekcji Arboretum SGGW w Rogowie. Celem badań była wery- fikacja gatunków grzybów zasiedlających fyllosferę azalii pontyjskiej oraz porównanie składu gatunkowego grzybów na naturalnym stanowisku i w arboretach. Analizie mykologicznej poddano liście zdrowe, porażone i opadłe. Stwierdzono, że zbio- rowiska grzybów bytujących w fyllosferze azalii pontyjskiej na stanowisku naturalnym i w ar- boretach różniły się składem gatunkowym i liczbą kolonii. Gatunkami wyodrębnionymi w naj- większej liczbie kolonii ze zdrowych liści azalii pontyjskiej były: A. alternata, Ph. cyclaminis, E. nigrum, Ph. medicaginis i B. cinera, z liści porażonych: A. alternata, E. nigrum, Ph. cyclaminis, S. fimicola, T. viride i A. phaeospermum, a z liści opadłych: E. nigrum, A. alternata, S. fimicola, Ph. cyclaminis i B. cinerea, co wskazuje, że większość z nich w okresie wegetacji stale zasiedla liście i uszkadza je, co prowadzi do ich przedwczesnego opadania. Zasiedlenie porażonych liści azalii w arboretach przez porównywalną liczbę kolonii i gatunków grzybów (w tym pa- togenów), znacznie większą niż w rezerwacie, może świadczyć o wpływie sąsiadujących roślin żywicielskich na ich stan zdrowotny. Kolonizacja fyllosfery azalii pontyjskiej w arboretach w Bolestraszycach i Rogowie przez dużo większą liczbę kolonii i gatunków grzybów, niż w wa- runkach naturalnego stanowiska w Kołacznii, świadczy o wzmożonej presji grzybów w środo- wiskach arboretów. 2013-12-20T14:47:50+0100 Polish Botanical Society