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Symptoms of Cytospora canker on apple trees in the Semirom region. (A and B) Dieback of a 25-yr-old Golden Delicious cultivar of apple tree following the entire girdling of the trunk by a canker. (C) Diffuse resinous twig cankers on Golden Delicious cultivar (D & E) Conidiomata of a Cytospora species on Red Delicious cultivar.
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Context 1
... trees ( Malus pumila Mill.) are widely planted in the Semirom region of Isfahan Province in Iran. Unfortunately, decline of mature apple trees in this region is generally caused by fungal disease, especially Cytospora canker. Cytospora canker is characterized by diffuse resinous branch cankers, with fruiting bodies of the causal fungi usually forming on infected parts. Cankers first occur on the lower branches, and then affect limbs progressively higher up the tree ( Fig. 1). The damage caused by this disease has attracted attention from orchardists as well as plant pathologists. Species of the genus Cytospora Ehrenb., and their related teleomorphs, are among the major causal agents of annual and perennial canker diseases and sudden death of many hardwood and coniferous trees, rarely herbaceous plants and monocots (Adams et al. , 2005). Members of Cytospora are associated with cankers and dieback on a wide range of trees and shrubs (Farr et al. , 1989; Speilman, 1985). Cytospora canker, caused by species of the genus Cytospora Ehrenb., is a worldwide problem and affects more than 70 species of woody shrubs and trees. The genus Cytospora was first described by Ehrenberg (1818). Cytospora refers to the anamorphic (asexual) stage of the causal fungi commonly found forming cankers. Numerous species of Cytospora are listed as causal agents of Cytospora cankers. However, species identification is difficult, because Cytospora fruiting and vegetative structures, as well as spore size, vary greatly even in the isolates of the same species (Spielman, 1985). The species of Cytospora is the anamorphs of Valsa Fr., Leucostoma (Nitschke) Höhn., Valsella Fuckel and Valseutypella Höhn. (Adams et al ., 2005). Fruiting bodies consist of stromata that usually contain either labyrinthine chambers, having filamentous conidiophores and allantoid hyaline conidia. In moist conditions, the conidia exude from the fruiting bodies in gelatinous matrices, usually as yellow, orange, red or pallid droplets or tendrils (Adams et al ., 2006; Sutton, 1980). Kobayashi (1970) in Japan, Gvritishvili (1982) and Vasilyeva (1994) in the former Union of Soviet Socialist Republics (USSR), Spielman (1983, 1985) for North American species on hardwoods and Adams et al . (2005, 2006) in South Africa, described the numerous species of genus of Cytospora . The first report on species of genus Cytospora in Iran was published by Fragozo (1918) to introduce Cytospora silenes Gonz. Frag. on Silene boryi Boiss. Thereafter, other researchers such as Petrak and Esfandiari (1941), Esfandiari (1946, 1948), Steyeart (1953), Ershad (1995), Ashkan (1979), Fotouhifar (2007) and Fotouhifar et al. (2007, 2008) introduced many other species of the genus Cytospora in Iran. These taxa have however, not been extensively investigated. Thus, awareness of existing species is essential for effective disease management. The main objective of the present study was to identify Cytospora species associated with canker diseases on apple trees in Semirom region of Iran. The apple orchards with dieback and canker symptoms were obesreved during spring and autumn of year 2007 that cankered twigs showed fruiting bodies of Cytospora spp. and their related teleomorphs were collected. A total of 170 infected twigs were collected from apple orchards almost all regions of the Semirom. The geographic origins of the collected isolates are listed in Table 1. Of these, 114 fungal specimens belonging to different anamorphic and teleomorphic species of this group of fungi were selected using morphological characteristics of sexual and asexual fruiting bodies (Fig. 1). Single spore isolation of fungi from infected host tissues with fruiting bodies was carried out by removing a mass of conidia from the surface of the specimens and spreading the suspension on the surface of agar plates. Single germinating spores were picked off and placed on fresh plates. Alternatively, plant tissues were cut in almost 5 mm diameter discs and placed in 70% ethanol for 1min and then surface sterilized by brief flaming. Masses of conidia from fruting bodies were discharged by placing the treated tissues in a moist chamber for 1hr at 25oC. Small amount of conidial mass from a single fruiting body was streaked on water agar medium using sterile needle and then the plates were incubated at 25oC for 24hr. If perithecia were presented in infected tissues, the contents of a single perithecium were similarly transferred to an agar plate. Single-spore isolates were obtained by transferring 3-10 germinated conidia or ascospores to PDA plates separately (Fotouhifar, 2007). Colors of the surface and reverse parts of the pure fungal colonies were compared using a color chart of (Rayner, 1970). Identification of species were based on morphological features of the sexual and asexual fruiting bodies produced on infected plant tissues. For this purpose, thin cross sections were prepared by hand from fruiting bodies. Morphological characteristics of the fruiting bodies including; size and arrangement of stromata, presence or absence of conceptacle in stromata, number and diameter of ostioles per disc, color, shape and size of discs, arrangement type of locules and perythecia, size and number of perithecia, size and shape of conidiophores and asci, size of conidia and ascospores were determined using a dissecting microscope. Microscopic measurements were made with a calibrated microscope. For each isolate, over 30 conidiomata were sectioned and diameters of 50 conidia were measured under an Olympus light microscope (SZH10) . If the perithecia were presented, over 50 perithecia were sectioned and then over 100 ascospores were measured under an Olympus microscope. For other morphological features, at least 50 specimens were measured. Representative isolates and samples were deposited at the Iranian Research Institute of Plant Protection (IRAN, Tehran, Iran). Isolates were placed in three genera based on their morphological features including; Cytospora , Valsa and Leucostoma . In the genus Cytospora , the following species were identified; Cytospora cincta, C. schulzeri, C. leucostoma and C. chrysosperma . In the genus Valsa only Valsa malicola was identified and in the genus Leucostoma also a single species, Leucostoma cinctum was identified. Out of 107 isolates studied, 50 isolates belonged to Valsa malicola (anamorph: Cytospora schulzeri ), 51 isolates belonged to Leucostoma cinctum (anamorph ; Cytospora cincta ), three isolates belonged to C. leucostoma , and finally, three isolates belonged to C. chrysosperma . The distinctive features of the identified species are shown as ...
Context 2
... trees ( Malus pumila Mill.) are widely planted in the Semirom region of Isfahan Province in Iran. Unfortunately, decline of mature apple trees in this region is generally caused by fungal disease, especially Cytospora canker. Cytospora canker is characterized by diffuse resinous branch cankers, with fruiting bodies of the causal fungi usually forming on infected parts. Cankers first occur on the lower branches, and then affect limbs progressively higher up the tree ( Fig. 1). The damage caused by this disease has attracted attention from orchardists as well as plant pathologists. Species of the genus Cytospora Ehrenb., and their related teleomorphs, are among the major causal agents of annual and perennial canker diseases and sudden death of many hardwood and coniferous trees, rarely herbaceous plants and monocots (Adams et al. , 2005). Members of Cytospora are associated with cankers and dieback on a wide range of trees and shrubs (Farr et al. , 1989; Speilman, 1985). Cytospora canker, caused by species of the genus Cytospora Ehrenb., is a worldwide problem and affects more than 70 species of woody shrubs and trees. The genus Cytospora was first described by Ehrenberg (1818). Cytospora refers to the anamorphic (asexual) stage of the causal fungi commonly found forming cankers. Numerous species of Cytospora are listed as causal agents of Cytospora cankers. However, species identification is difficult, because Cytospora fruiting and vegetative structures, as well as spore size, vary greatly even in the isolates of the same species (Spielman, 1985). The species of Cytospora is the anamorphs of Valsa Fr., Leucostoma (Nitschke) Höhn., Valsella Fuckel and Valseutypella Höhn. (Adams et al ., 2005). Fruiting bodies consist of stromata that usually contain either labyrinthine chambers, having filamentous conidiophores and allantoid hyaline conidia. In moist conditions, the conidia exude from the fruiting bodies in gelatinous matrices, usually as yellow, orange, red or pallid droplets or tendrils (Adams et al ., 2006; Sutton, 1980). Kobayashi (1970) in Japan, Gvritishvili (1982) and Vasilyeva (1994) in the former Union of Soviet Socialist Republics (USSR), Spielman (1983, 1985) for North American species on hardwoods and Adams et al . (2005, 2006) in South Africa, described the numerous species of genus of Cytospora . The first report on species of genus Cytospora in Iran was published by Fragozo (1918) to introduce Cytospora silenes Gonz. Frag. on Silene boryi Boiss. Thereafter, other researchers such as Petrak and Esfandiari (1941), Esfandiari (1946, 1948), Steyeart (1953), Ershad (1995), Ashkan (1979), Fotouhifar (2007) and Fotouhifar et al. (2007, 2008) introduced many other species of the genus Cytospora in Iran. These taxa have however, not been extensively investigated. Thus, awareness of existing species is essential for effective disease management. The main objective of the present study was to identify Cytospora species associated with canker diseases on apple trees in Semirom region of Iran. The apple orchards with dieback and canker symptoms were obesreved during spring and autumn of year 2007 that cankered twigs showed fruiting bodies of Cytospora spp. and their related teleomorphs were collected. A total of 170 infected twigs were collected from apple orchards almost all regions of the Semirom. The geographic origins of the collected isolates are listed in Table 1. Of these, 114 fungal specimens belonging to different anamorphic and teleomorphic species of this group of fungi were selected using morphological characteristics of sexual and asexual fruiting bodies (Fig. 1). Single spore isolation of fungi from infected host tissues with fruiting bodies was carried out by removing a mass of conidia from the surface of the specimens and spreading the suspension on the surface of agar plates. Single germinating spores were picked off and placed on fresh plates. Alternatively, plant tissues were cut in almost 5 mm diameter discs and placed in 70% ethanol for 1min and then surface sterilized by brief flaming. Masses of conidia from fruting bodies were discharged by placing the treated tissues in a moist chamber for 1hr at 25oC. Small amount of conidial mass from a single fruiting body was streaked on water agar medium using sterile needle and then the plates were incubated at 25oC for 24hr. If perithecia were presented in infected tissues, the contents of a single perithecium were similarly transferred to an agar plate. Single-spore isolates were obtained by transferring 3-10 germinated conidia or ascospores to PDA plates separately (Fotouhifar, 2007). Colors of the surface and reverse parts of the pure fungal colonies were compared using a color chart of (Rayner, 1970). Identification of species were based on morphological features of the sexual and asexual fruiting bodies produced on infected plant tissues. For this purpose, thin cross sections were prepared by hand from fruiting bodies. Morphological characteristics of the fruiting bodies including; size and arrangement of stromata, presence or absence of conceptacle in stromata, number and diameter of ostioles per disc, color, shape and size of discs, arrangement type of locules and perythecia, size and number of perithecia, size and shape of conidiophores and asci, size of conidia and ascospores were determined using a dissecting microscope. Microscopic measurements were made with a calibrated microscope. For each isolate, over 30 conidiomata were sectioned and diameters of 50 conidia were measured under an Olympus light microscope (SZH10) . If the perithecia were presented, over 50 perithecia were sectioned and then over 100 ascospores were measured under an Olympus microscope. For other morphological features, at least 50 specimens were measured. Representative isolates and samples were deposited at the Iranian Research Institute of Plant Protection (IRAN, Tehran, Iran). Isolates were placed in three genera based on their morphological features including; Cytospora , Valsa and Leucostoma . In the genus Cytospora , the following species were identified; Cytospora cincta, C. schulzeri, C. leucostoma and C. chrysosperma . In the genus Valsa only Valsa malicola was identified and in the genus Leucostoma also a single species, Leucostoma cinctum was identified. Out of 107 isolates studied, 50 isolates belonged to Valsa malicola (anamorph: Cytospora schulzeri ), 51 isolates belonged to Leucostoma cinctum (anamorph ; Cytospora cincta ), three isolates belonged to C. leucostoma , and finally, three isolates belonged to C. chrysosperma . The distinctive features of the identified species are shown as ...
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Citations
... Apple canker disease is caused usually by the species in Botryosphaeriaceae and Valsaceae families in Iran (Ashkan 1994;Mehrabi et al. 2011;Arzanlou and Bakhshi 2012;Nourian et al. 2021) and in other regions of the world (Brown and Britton 1986;Proffer and Jones 1989;Adams et al. 2006;Phillips et al. 2012;Nabi et al. 2020). D. bulgarica was first reported from apple trees displaying canker symptoms in Bulgaria (Phillips et al. 2012), and thereafter, in Iran (Arzanlou and Bakhshi 2012;Nourian et al. 2021). ...
Apple (Malus domestica Borkh) is one of the most consumed and nutritious fruits. Iran is one of the main producers of the apple in the world. Diplodia bulgarica is the major causal agent of apple tree decline in Iran. Biological control is a nature-friendly approach to plant disease management. Trichoderma zelobreve was isolated from apple trees infected with Diplodia bulgarica in West Azarbaijan province of Iran. The results showed that T. zelobreve strongly inhibited the colony growth of D. bulgarica. In vivo assay on detached branches of apple tree cv. Golden Delicious using T. zelobreve mycelial plug showed that canker length/stem length (CL/SL) and canker perimeter/stem perimeter (CP/SP) indices decreased by 76 and 69%, respectively, 21 days after inoculation. Additionally, wettable powder formulation (WPF) containing the antagonistic fungus "T. zelobreve" decreased CL and CP/SP by 75 and 67%, respectively, 6 months after inoculation. Moreover, canker progress curves and the area under the disease progress curve (AUDPC) supported these findings. The growth temperatures of the antagonist and pathogen were similar, indicating the adaptation of T. zelobreve for biocontrol of apple canker caused by D. bulgarica. The results also showed that T. zelobreve-based WPF stored at 25 °C assure excellent shelf life at least 4 months, allowing the bioproduct to be stored at room temperature, which is a great advantage and cost-effective option.
... However, recent studies employing molecular phylogeny revealed many cryptic species with similar morphology on the same host of known species of this genus [11][12][13][14][15]. For example, up to 28 Cytospora species were discovered from Eucalyptus spp. in South Africa with the help of DNA sequence evidence [2], eight from willow (Salix spp.) trees in China [16], six from Castanea mollissima in China [17], six from Populus hosts in China [18] and six from apple trees in Iran [19]. The taxonomy of Cytospora is currently more dependent on combined evidence of DNA sequence data, morphological features and ecology than species morphology and host associations [1,20]. ...
Cytospora (Cytosporaceae, Diaporthales) is a fungal genus that usually inhabits plants as endophytes, saprobes, as well as pathogens. Species of this genus are characterized by possessing allantoid hyaline conidia and ascospores. Samples with typical Cytospora canker symptoms on Prunus davidiana, P. padus and Salix sp. were collected in Tibet and Xinjiang, China. Species were identified using both morphological and molecular approaches of combined loci of internal transcribed spacer region rDNA (ITS), the partial actin (act) region, RNA polymerase II second largest subunit (rpb2), the translation elongation factor 1-alpha (tef1) gene and the partial be-ta-tubulin (tub2) gene. Six isolates in the present study formed three distinct clades from previously known species. Cytospora hejingensis sp. nov. from Salix sp., C. jilongensis sp. nov. from P. davidiana and C. kunsensis from P. padus were proposed herein. The current study improves the understanding of species concept in Cytospora.
... Cytospora species and their related teleomorphs are considered to be among the main causal agents of annual and perennial canker diseases and sudden decline of diverse coniferous and hardwood trees, hardly monocots and herbaceous plants (Adams et al., 2004). Six species C. leucostoma, C. cincta, C. chrysosperma, C. schulzeri, Leucostoma cinctum and Valsa malicola of three genera were causal agents of cytospora canker disease of apple trees in Semirom region, Isfahan province, Iran (Mehrabi et al., 2011). Also, C. cincta was reported as the most widespread and aggressive canker causal species in apple production hubs of Iran (Nourian et al., 2021). ...
Fungal stem cankers are common and destructive diseases in apple orchards. Cytospora cincta and Neoscytalidium dimidiatum are the apple canker causal agents in Iran. Formulated biocontrol agents of plant diseases are considered alternatives to synthetic pesticides in sustainable agriculture. The results showed that Trichoderma zelobreve T20 strongly inhibited the in vitro growth of C. cincta and N. dimidiatum . Wettable powder formulation (WPF) based on T. zelobreve T20 was developed to control apple canker caused by C. cincta and N. dimidiatum . The dual culture test showed that T20 inhibited C. cincta and N. dimidiatum growth by 55.19% and 44.07% respectively. T20 culture filtrate reduced the mycelial growth of C. cincta (72.22%) but showed no activity against N. dimidiatum . T20‐based WPF inhibited C. cincta (94.62%) and N. dimidiatum (14.71%) growth on detached branches of 2‐year‐old apple trees (golden delicious cultivar). Also, T20‐based WPF inhibited apple tree canker caused by C. cincta and N. dimidiatum by 82.8% and 60% respectively. The performance of T20‐based WPF on apple trees was significantly better than detached branches. The spore count of T20‐based WPF was about 71.54% of the original count after 4 months, marking its suitable shelf life. T20‐based WPF could be considered a promising control measure against apple canker pathogens.
... are well-known opportunistic fungi, having a cosmopolitan distribution and commonly occurring in healthy woody plants as asymptomatic endophytes. However, they can also cause diseases in various woody plants, usually under conditions of stress (Adams et al. 2005, Mehrabi et al. 2011, Zhang et al. 2012, Du et al. 2013, Palavouzis et al. 2015). An extensive study by Adams et al. (2006) identified 14 Cytospora spp. ...
Euphorbia mauritanica is a succulent shrub that is indigenous to South Africa and widely distributed throughout the country. Dying plants have been observed in their natural habitat in the Northern and Western Cape Provinces of South Africa in recent years. Stems displaying lesions were collected and the emerging cultures were identified based on ITS, LSU, ACT , RPB2 , TEF1 and/or TUB2 sequence data. Four filamentous fungi were consistently observed and isolated. One was identified as Alanphillipsia ( Ala .) aloes , and the other three were new to science and are described here as Cytospora euphorbiicola sp. nov. , Nothomicrosphaeropsis namakwaensis sp. nov. and Austrophoma ( Aus .) euphorbiae gen. et sp. nov. These new species and Ala. aloes were the most commonly encountered, and their pathogenicity was tested on E. mauritanica plants in a greenhouse trial. All four species gave rise to lesions that were significantly larger than those associated with the controls, but they were not significantly different to each other. Although the lesions associated with the inoculations were well-developed, they did not give rise to plant death, suggesting that they are not responsible for the large-scale die-off of E. mauritanica in the field. The primary cause of the death of E. mauritanica in the studied area remains unknown and could be due to environmental factors such as has been found with the die-off of Euphorbia ingens in South Africa.
... It is indicated that Cytospora spp., which is among fungal disease factors, causes canker and retrospective death disease in more than 100 plant species, including apple trees worldwide (Adams et al. 2005(Adams et al. , 2006Pan et al. 2018). In many studies, the species that cause canker disease in apple trees; C. cincta, C. schulzeri, C. leucostoma, C. chrysosperma, C. nivea, C. sacculus, C. melnikii, C. mali, C. carphosperma, C. parasitica, C. rubescens, C. microspora, C. calvillae, C. personata, C. leucosticta, Valsa americana, V. ceratosperma, V. malicola, V. papyriferae and V. melastoma (Proffer and 1989;Ashkan and Hedjaroude 1993;Surve-Iyer et al. 1995;Wang et al. 2007Wang et al. , 2011Wang et al. , 2014Suzaki 2008;Fotouhifar et al. 2010;Mehrabi et al. 2011;Norphanphoun et al. 2017;Lawrence et al. 2018;Ma et al. 2018). This disease causes significant crop losses worldwide (Adams et al. 2005(Adams et al. , 2006. ...
Cytospora spp. is a cause of canker and dieback disease in many plant species, including apple trees worldwide, and causes significant crop losses worldwide. In this study, samples of Cytospora were collected from symptomatic branches in apple trees in the Eğirdir district of Isparta province, Türkiye. Cytospora isolates identification were determined by internal transcribed spacer (ITS), ef1‑α (translation elongation factor 1-alpha) and large subunit (LSU) sequence analysis. In molecular analyses, the species isolated from apple trees were identified as Cytospora parasitica and C. sorbicola. nrITS sequence lengths between 456 and 655 base pairs, ef1‑α sequence lengths between 538 and 647 base pairs and nrLSU sequence lengths between 1015 and 1314 base pairs were determined. In addition, π = nucleotide diversity, 0.021220 for ITS sequence, π = 0.021220, for ef1‑α sequence π = 0.085317 and for LSU sequence π = 0.009499 were determined. Also, in phylogenetic trees constructed using ITS, ef1‑α and LSU sequences C. parasitica and C. sorbicola species appeared in separate branches. As a result, nrITS, ef1‑α and nrLSU sequences were efficient in the identification and phylogenetic analysis of Cytospora species. Cytospora sorbicola is recorded as being associated with apple canker disease in Türkiye for the first time.
... There are diseases in all parts of agriculture of ornamental flowers [1], apple trees [2], walnut trees [3], and cherry trees [4], even in vineyards. These diseases appear on the leaves of tree trunks and even the fruit of these trees. ...
Due to the damage that various tree diseases cause to agricultural fields, there are always different methods to deal with them. This paper proposes a new algorithm to identify three common grapevine diseases: Downey Mildew, Anthracnose, and Powdery Mildew. This new algorithm is based on the Faster Region-based Convolutional Neural Networks (R-CNN) with an Enhanced VGG16 model. The proposed Enhanced VGG16 model can diagnose better these three types of diseases. Experimental results show that the proposed algorithm has 0.53%, 0.912%, 2.759%, and 7.268% improvement in the mean Average Precision (mAP) criterion compared to ResNet50, VGG16, GoogLeNet, and AlexNet networks, respectively. The precision of the proposed method is better than other methods, and the number of layers used in it is acceptable compared to other methods.
... Even though Cytospora species are principally known as weak pathogens, they negatively affect the longevity and productivity of fruit trees worldwide and cause chronic wood infections on fruit trees such as Malus spp. (Adams et al., 2005(Adams et al., , 2006Azizi et al., 2020a;Biggs 1989;Bills 1996;Christensen 1940;Fan et al., 2014aFan et al., , 2014bFan et al., , 2015aFan et al., , 2015bGonz alez and Tello 2011;Lawrence et al., 2018;Mehrabi et al., 2011;Pan et al., 2020;Sinclair et al., 1987;Wang et al., 2011Wang et al., , 2020Zhu et al., 2018). Disease symptoms initially appear on trunk and branches as slightly sunken areas on bark with brown discoloration in the wood that might result in cracking and scaling-off of the bark with disease progress. ...
... To date, 24 Cytospora species have been reported as the causal agent of apple canker disease worldwide, among which Cytospora ambiens, C. chrysosperma, C. cincta, C. germanica, C. leucostoma, C. paratranslucens, C. rubescens, C. salicina, and C. schulzeri have been recorded on apple trees in Iran (Ashkan 1994;Ashkan and Hedjaroude 1993;Azizi et al., 2020a;Fotouhifar et al., 2010;Ma et al., 2018;Mehrabi et al., 2011;Wang et al., 2011Wang et al., , 2020. As consequences of global climate change during last two decades in the mainland of Iran (including drought stress and high temperatures), canker and die-back diseases have become a major threat for Iranian apple industry. ...
... Notes: Cytospora chrysosperma is the type species of the genus Cytospora and has been reported as canker disease with a wide host range in the world (Adams et al., 2006;Fan et al., 2014b;Tai 1979;Teng 1963;Zhuang 2005). According to earlier studies, several plant genera including Armeniaca, Crataegus, Ficus, Fraxinus, Juglans, Ligustrum, Malus, Morus, Olea, Persica, Platanus, Populus, Prunus, Robinia, Salix, Tamarix, Thuja, and Vitis are hosts to C. chrysosperma in Iran (Arzanlou and Narmani 2015;Azizi et al., 2020a;Bagherabadi et al., 2017;Fotouhifar et al., 2010;Mehrabi et al., 2011). In this study, the morphology of IRAN 4196C isolate is similar to C. chrysosperma in having multilocular conidiomata and hyaline, unicellular, elongate-allantoid, eguttulate, 4e5 Â 1 mm conidia (Adams et al., 2006). ...
In recent years, canker and die-back diseases have become a growing threat for the productivity and longevity of apple orchards in Iran. In this study, 131 Cytospora isolates were recovered from symptomatic tissues of apple trees in apple orchards of Iran. Multigene phylogenetic inference based on combined sequence data of ITS, act, rpb2, and tef1-α loci, supplemented with morphological characteristics and pathogenicity assay revealed four novel Cytospora species which were described as C. avicennae, C. azerbaijanica, C. ershadii, and C. iranica, and four known species, namely C. chrysosperma, C. parasitica, C. paratranslucens, and C. sorbicola. Also, C. sorbicola is newly reported on apple trees worldwide. Koch's postulates were fulfilled to confirm that all eight species in this study were pathogenic on apple trees in Iran, among which C. sorbicola was the most intensive species. The results of this study further highlight rich diversity among Cytospora species occurring on apple trees, revealing several novel Cytospora species on this host. The host range, geographical distribution, and economic significance of novel species on apple industry remains to be studied.
... Thus far, about 24 species of Cytospora and their sexual allies have been reported from Malus spp. Worldwide [30][31][32][33] , of which 14 species recognized in Iran 32,34,35 . However, taxonomic status of most of these species has not been approved through molecular approaches. ...
... Apple is one of the main hosts that suffer severe damage from the Cytospora canker disease 31,55,56 . At present, 24 Cytospora species have been reported as causal agents of canker disease in apple trees worldwide and 14 species have been recorded in Iran 30,32,33,35 . The results of our study indicated that more extensive pathogen surveys of apple production regions should be undertaken. ...
Apple is the most important fruit tree in West Azarbaijan province of Iran. However, a disease with crown and collar canker and necrosis was observed in three young apple orchards in Urmia, affected 15% and 1% of ‘Red Delicious’ and ‘Golden Delicious’ cultivars, respectively. A fungus with typical characteristics of the asexual morph of Cytospora was regularly isolated from the diseased tissues. Morphological characteristics and phylogenetic analysis inferred from the combined dataset of the ITS–rDNA, parts of LSU, tef1-α, rpb2 and act1 genes revealed that the isolates represent a new species of Cytospora, described herein as Cytospora balanejica sp. nov.. Pathogenicity of all isolates was confirmed on the cv. ‘Red Delicious’ based on Koch’s postulates. Also, the reaction of 12 apple cultivars was assessed against five selected isolates with higher virulence. Results showed that except cv. ‘Braeburn’ which did not produce any symptoms of infection, the other 11 cultivars showed characteristic symptoms including sunken and discolored bark and wood. The mean length of discolored area was different among the 11 so-called susceptible cultivars, hence cvs. ‘M4’ and ‘Golden delicious’ had the highest and the lowest lesion length, respectively. Moreover, the aggressiveness of five tested isolates was varied and the isolates BA 2–4 and BA 3–1 had the highest and lowest aggressiveness, respectively. Based on our observations on the potential ability of the fungus in causing the disease on young and actively growing apple trees, it will be a serious threat to apple cultivation and industry.
... regular tracking operations, these harmful factors should be identified and implemented with a practical and managed program with the minimum consumption of pesticides. There are diseases in all parts of agriculture of ornamental flowers [1], apple trees [2], walnut trees [3], and cherry trees [4], even in vineyards. These diseases appear on the leaves of tree trunks and even the fruit of these trees. ...
Diseases of grape leaves are destructive because they spread very quickly. Therefore, they should be detected and tackled fast. This study proposes a novel Enhanced VGG16 model for detecting, identifying, and classifying three widespread diseases in grape leaves. These diseases include Downey Mildew, Anthracnose, and Powdery Mildew. The data are automatically gathered with the assistance of photos taken with a quadcopter from the grapevine garden. The main central system analyzes the images received from the quadcopter to identify diseases. If it finds any of the three diseases, it sends the command to the hexacopter to spray pesticide into the grapevine garden location where the disease is found. The proposed method using the Enhanced VGG16 model with Faster Region-based Convolutional Neural Networks (R-CNN) is compared with different networks, including VGG16, GoogLeNet, ResNet50, and AlexNet. The experimental results on the grape leaf diseases demonstrated that the proposed method achieves the mean Average Precision) mAP (criterion improvements of 0.53%, 0.912%, 2.759%, and 7.268% compared with the ResNet50, VGG16, GoogLeNet, and AlexNet networks, respectively. Also, the average accuracy of the proposed Enhanced VGG16 model is 99.6%, which is 0.437–1.91% higher than other models. The Enhanced VGG16 has the best precision, and the number of layers is acceptable, although it is not less.
... Cytospora canker is devastating for forest as well as urban trees causing mortality and dieback of these woody hosts. A number of studies have been carried out for isolation and characterization of this fungus from various plants for understanding of its host range, geographical relationships (Kepley, 2000;Adams et al., 2006), genetic diversity (Abbasi et al., 2011), physiology to reduce the damage (Mehrabi et al., 2011), morphological and phylogenetic studies (Fan et al., 2014), etc. ...
