scholarly journals First Report of Oidium anamorph of Erysiphe hypophylla Causing Powdery Mildew on Leafy Lespedeza (Lespedeza cyrtobotrya) in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 287-287 ◽  
Author(s):  
H. B. Lee
Keyword(s):  
Sequence Analysis ◽  
Powdery Mildew ◽  
Far East ◽  
Its Region ◽  
Agricultural Science ◽  
First Report ◽  
Rdna Its ◽  
Sand Control ◽  
Quercus Species ◽  
The World

Leafy lespedeza (Lespedeza cyrtobotrya Miq.) is a deciduous shrub in the pea family (Fabaceae) that occurs in areas of East Asia including Korea, China, and Japan. It has been commonly used as a fence plant and for sand control in Korea. In late October 2011, a powdery mildew disease was observed on leafy lespedeza in several areas near Gwangju River, Gwangju, Korea. Symptoms appeared late in October when temperature fluctuation was high. Major symptoms included scattered white powdery to cottony colonies on both surfaces of the leaves which spread to stems, causing a minor chlorosis and distortion. Conidia were formed singly on conidiophores with 2 to 4 (commonly 3) septa including basal septum, primary conidia ellipsoid, apex rounded to subtruncate, base truncate; and secondary conidia subcylindrical to oblong when mature, and ends truncate. The size was 26.4 to 43.2 (av. 35.1) × 11.2 to 13.2 (av. 11.3) μm. Conidiophores were erect, cylindrical, wider at apex than foot cell, and straight or slightly flexuous in foot cells. The size was 60.1 to 81.3 (av. 78.1) × 6.2 to 12.1 (av. 8.3) μm. Chasmothecia were not observed. Morphologically, the conidia and conidiophores of our strain (EML-LCPW1) were very similar to those of Erysiphe hypophylla (syn. Microsphaera hypophylla) (4). From extracted genomic DNA, the internal transcribed spacer (ITS) region inclusive of 5.8S and 28S rDNA were amplified with ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′), LR5F (5′-GCTATCCTGAGGGAAAC-3′), LROR (5′-ACCCGCTGAACTTAAGC-3′), and LR5F primer sets, respectively. Based on the morphology and ITS rDNA sequence analysis, the fungus was identified as E. hypophylla. rDNA ITS and 28S homologies of the fungus (EML-LCPW1, GenBank Accession Nos. JX512557 and JX512558) represented 100% (771/771) and 100% (775/775) identity values with E. hypophylla (AB292712 and AB292716, respectively) via NCBI BLASTn search of each isolate. The rDNA ITS (JX512557) and 28S (JX512558) sequence analysis revealed that the causal fungus matched E. hypophylla, forming a HypophyllaAlphitoides clade as Takamatsu et al. suggested that E. hypophylla is conspecific to E. alphitoides (3). So far, it has been known that E. communis, E. glycines var. lespedezae, and E. lespedezae cause powdery mildews on Lespedeza plants in the world (1). In Korea, only one Erysiphe species, E. lespedezae (= E. pisi), has been reported to cause powdery mildew on Lespedeza plants including L. bicolor and L. cyrtobotrya (2). In addition, 10 records with respect to Oidium sp. have been found on Lespedeza spp., including L. cyrtobotrya from Japan and L. chinensis from China (1). However, powdery mildew on Lespedeza plants, including leafy lespedeza caused by E. hypophylla, has not been reported in Korea or elsewhere in the world. This fungus has been reported in association with numerous oak (Quercus) species in nearby countries such as China and Russia (Far East), showing that it may be a potential source of inoculum in Korea as well. To our knowledge, this is the first report of Oidium anamorph of E. hypophylla on leafy lespedeza (L. cyrtobotrya) in Korea. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , October 9, 2012. (2) H. D. Shin. Page 320 in: Erysiphaceae of Korea. National Institute of Agricultural Science & Technology, Suwon, Korea, 2000. (3) S. Takamatsu et al. Mycoscience 47:367, 2006. (4) S. Takamatsu et al. Mycol. Res. 111:809, 2007.

scholarly journals First Report of Powdery Mildew Caused by Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii on Papaya in Taiwan

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1188-1188 ◽  
Author(s):  
J.-G. Tsay ◽  
R.-S. Chen ◽  
H.-L. Wang ◽  
W.-L. Wang ◽  
B.-C. Weng
Keyword(s):  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Its Region ◽  
Podosphaera Xanthii ◽  
Oidium Neolycopersici ◽  
First Report ◽  
Plastic Bags ◽  
The World ◽  
Golovinomyces Cichoracearum ◽  
Powdery Mildew Fungi

Powdery mildew can be found in most papaya (Carica papaya L.) fields during the winter and spring seasons in Taiwan. It usually causes severe yellowing of the leaf lamina and petiole and serious defoliation. Three types of powdery mildew fungi were isolated from papaya leaves in Chiayi City (23.28°N, 120.28°E) at the beginning of 2008. Conidia of the first one were single, globose, hyaline, and 24 to 36 × 14 to 18 μm (average 30.2 × 15.6 μm) without fibrosin bodies and with straight or occasionally flexuous conidiophores at the base. The second one had short pseudo-chains of two to four conidia which were ellipsoidal to ovoid, hyaline, and 24 to 40 × 12 to 16 μm (average 29.7 × 13.4 μm) without fibrosin bodies. The third type had chains of ellipsoidal conidia that were hyaline, 24 to 28 × 12 to 16 μm (average 26.3 × 14.4 μm) and contained fibrosin bodies. To confirm the identity of the three fungi, the internal transcribed spacer (ITS) region of rDNA was amplified using the primer pairs G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/Ed2 (5′-CGC GTA GAG CCC ACG TCG GA-3′), G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/On2 (5′-TGT GAT CCA TGT GAC TGG AA-3′), and S1 (5′-GGA TCA TTA CTG AGC GCG AGG CCC CG-3′)/S2 (5′-CGC CGC CCT GGC GCG AGA TAC A-3′). The alignment of obtained sequences (GenBank Accession Nos. GU358452, 507 bp; GU358451, 580 bp; and GU358450, 455 bp) showed a sequence identity of 100, 99, and 99% with the ITS sequences of Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii (GenBank Accession Nos. FJ378880, EU909694, and GQ927254), respectively. On the basis of morphological characteristics and ITS sequence similarities, these fungi were identified as E. diffusa (Cooke & Peck) U. Braun & S. Takam., O. neolycopersici L. Kiss, and P. xanthii (Castagne) U. Braun & S. Takam., respectively (1,3). Single colonies on papaya leaves infected with powdery mildew were identified in the laboratory and maintained on papaya leaves as inoculum. Pathogenicity was confirmed through inoculations by gently pressing a single colony of each fungus onto leaves of healthy papaya seedlings (cv. Horng-Fe). Five seedlings were inoculated for each fungus and then covered with plastic bags for 2 days. Five noninoculated seedlings served as control. After inoculation, treated plants were maintained separately from the control in different rooms of a greenhouse at 25°C under natural daylight conditions. Seven days after inoculation, typical symptoms of powdery mildew were observed on inoculated plants, but not on noninoculated plants. The same species from diseased lesions following artificial inoculation with each fungus were identified with light microscopy. Papaya was previously described as a host to O. caricae Noack in many tropical and subtropical areas of the world including Taiwan (2). However E. cruciferarum, Golovinomyces cichoracearum, Oidiopsis sicula, O. caricae, O. caricae-papayae, O. caricicola, O. indicum, O. papayae, Ovulariopsis papayae, P. caricae-papayae, P. macularis, P. xanthii, and Streptopodium caricae were reported to infect papaya (4). To our knowledge, this is the first report of papaya powdery mildew caused by E. diffusa and O. neolycopersici in the world and the first report of the three fungi found on papaya in Taiwan. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) H. S. Chien and H. L. Wang. J. Agric. Res. China 33:320, 1984. (3) L. Kiss et al. Mycol. Res. 105:684, 2001. (4) J. R. Liberato et al. Mycol. Res. 108:1185, 2004.

scholarly journals First Report of Powdery Mildew on Spanish Needles (Bidens bipinnata) Caused by Podosphaera xanthii in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (10) ◽  
pp. 1385-1385
Author(s):  
H. B. Lee ◽  
C. J. Kim ◽  
H. Y. Mun
Keyword(s):  
Powdery Mildew ◽  
Its Region ◽  
Broad Host Range ◽  
Pathogenicity Test ◽  
Podosphaera Xanthii ◽  
Tropical Regions ◽  
First Report ◽  
Rdna Its ◽  
Humid Condition ◽  
Primer Sets

Spanish needles (Bidens bipinnata L.) is an annual herb that belongs to a genus of flowering plants in family Asteraceae native to United States, and tropical regions around world. The plant produces important flavonoid compounds quercitin and hyperoside that function as anti-allergens, anti-inflammatories, anti-microbials, and anti-cancer agents. Between July and October 2011 and 2012, white superficial mycelia were observed initially on leaf and stem portions, but later progressed to the flower head. Surveys showed that the disease was widespread in Gwangju and most areas of South Korea. Abundant, necrotic, dark brown spots showing chasmothecia were frequently observed in October and were abundant on the adaxial surface of leaves. Chasmothecia were blackish brown to yellow without typical appendages. They ranged from 51.2 to 71.1 (mean 66.8) μm in diameter. Conidia were formed singly and the primary conidia were ellipsoid, rounded at the apex, truncated base, and ranged from 25.4 to 33.2 (mean 27.3) μm long × 10.2 to 12.2 (mean 11.3) μm wide. Conidiophores were erect, 60.1 to 101.3 (mean 98.3) μm long × 6.2 to 9.2 (mean 7.3) μm wide. From extracted genomic DNA, the internal transcribed spacer (ITS) region inclusive of 5.8S and 28S rDNA was amplified with ITS1F (5′-TCCGTAGGTGAACCTGCGG-3′) and LR5F (5′-GCTATCCTGAGGGAAAC-3′), and LROR (5′-ACCCGCTGAACTTAAGC-3′) and LR5F primer sets, respectively. rDNA ITS (GenBank Accession No. JX512555) and 28S (JX512556) homologies of the fungus (EML-BBPW1) represented 99.6% (532/534) and 100% (661/661) identity values with Podosphaera xanthii (syn. P. fusca) AB040349 and P. xanthii (syn. P. fusca) AB462798, respectively. The rDNA sequence analysis revealed that the causal fungus matched P. xanthii (syn. P. fusca), forming a xanthii/fusca group (3,4). A pathogenicity test was performed on three plants in a greenhouse. The treated leaves were sealed in vinyl pack in humid condition for 2 days. Seven days after inoculation, similar symptoms were observed on the inoculated Spanish needles plant leaves. No symptoms were observed on control plants treated with distilled water. Koch's postulates were fulfilled by re-observing the fungal pathogen on the inoculated leaves. Podosphaera (syn. Sphaerotheca) xanthii (or fusca) has been known as an ubiquitous species with a broad host range. So far, five records regarding P. xanthii (=P. fusca) have been found in plants of genus Bidens. P. xanthii has been reported to occur on B. cernua in Belarus and Switzerland. In addition, the powdery mildew species was reported to occur on B. frondosa and B. tripartita in Korea, Russia, and Switzerland (2). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on Spanish needles (B. bipinnata) in Korea. References: (1) U. Braun et al. Schlechtendalia 10:91, 2003. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 2012. (3) H. B. Lee. J. Microbiol. 51:1075, 2012. (4) S. Takamatsu, et al. Persoonia 24:38, 2010.

scholarly journals First Report of Powdery Mildew Caused by Podosphaera xanthii (syn. P. fusca) on Cocklebur in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 842-842 ◽  
Author(s):  
H. B. Lee
Keyword(s):  
Powdery Mildew ◽  
Natural Infection ◽  
Morphological Characteristics ◽  
Its Region ◽  
Xanthium Strumarium ◽  
Podosphaera Xanthii ◽  
First Report ◽  
Rdna Its ◽  
Causal Fungus ◽  
Powdery Mildew Pathogen

Cocklebur (Xanthium strumarium L., Asteraceae) is an annual broadleaf weed native to the Americas and eastern Asia. The plant is known as one of the worst competitive weeds in soybean fields and also is known to have some phytopharmacological or toxicological properties. In October 2011, a powdery mildew disease was observed on cocklebur growing in a natural landscape at Geomun Oreum located in Jeju Island, South Korea. Initial signs appeared as thin white colonies, which subsequently developed abundant growth on adaxial leaf surfaces. As the disease progressed, brown discoloration extended down infected leaves which withered. Conidia were formed singly and terminally on conidiophores. Primary conidia (20.3 to 28.6 [average 25.1] μm long × 11.1 to 15.2 [14.3] μm wide, n = 30) were ellipsoid with a round apex and truncate base. Conidiophores were straight or slightly curved and 60.1 to 101.7 (97.3) μm long × 8.2 to 13.2 (11.3) μm wide. Chasmothecia were not observed. No fibrosin bodies were observed in the conidia. Morphological characteristics were consistent with descriptions of Podosphaera xanthii (syn. P. fusca) (2,4). To confirm the identity of the causal fungus, the internal transcribed spacer (ITS) region inclusive of 5.8S and 28S rDNA was amplified from white patches consisting of mycelia and conidia on one leaf using ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and LR5F (5′-GCTATCCTGAGGGAAAC-3′), and LROR (5′-ACCCGCTGAACTTAAGC-3′) and LR5F primer sets, respectively. The resulting sequences were deposited in GenBank (Accession Nos. JX502022 and JX964999). A NCBI BLASTn search revealed that the rDNA ITS (JX502022) and 28S (JX964999) homologies of isolate EML-XSPW1 represented 99.6% (512/514) and 100% (803/803) identity values with those of P. xanthii (AB040330 and AB462792, respectively). The rDNA ITS and 28S sequence analysis revealed that the causal fungus clustered with P. xanthii (syn. P. fusca), falling into the Xanthii/Fusca phylogenetic group (2,4). Pathogenicity was confirmed through inoculations made by gently pressing infected leaves onto mature leaves of healthy cocklebur plants in the field in August. The six inoculated leaves were sealed in sterilized vinyl bags to maintain humid conditions for 2 days. Seven days after inoculation, symptoms similar to those observed under natural infection were observed on the inoculated plant leaves. No symptoms developed on the uninoculated control plants. A fungal pathogen that was morphologically identical to the fungus originally observed on diseased plants was also observed on inoculated plants. Erysiphe cichoracearum, E. communis, Oidium asteris-punicei, O. xanthimi, P. xanthii, and P. fuliginea have all been reported to cause powdery mildew on cocklebur (1). P. xanthii was first reported on X. strumarium in Russia (3). To our knowledge, this is the first report of powdery mildew on cocklebur caused by P. xanthii in Korea. The powdery mildew pathogen may represent an option for biocontrol of the noxious weed in the near future. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases , December 11, 2012. (2) H. B. Lee. J. Microbiol. 51:1075, 2012. (3) V. A. Rusanov and T. S. Bulgakov. Mikol. Fitopatol. 42:314, 2008. (4) S. Takamatsu et al. Persoonia 24:38, 2010.

scholarly journals First Report of Powdery Mildew Caused by Erysiphe arcuata on Lanceleaf Coreopsis (Coreopsis lanceolata) in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1827-1827 ◽  
Author(s):  
H. B. Lee
Keyword(s):  
Powdery Mildew ◽  
Invasive Plant ◽  
Signs And Symptoms ◽  
Morphological Data ◽  
Powdery Mildew Fungus ◽  
First Report ◽  
Rdna Its ◽  
The World ◽  
The Usa ◽  
Cut Foliage

Lanceleaf coreopsis (Coreopsis lanceolata L.) is a plant species of the genus Coreopsis in Asteraceae native to the USA. This plant is a bushy perennial species with finely cut foliage and showy round flowers and is increasing as plants used in landscaping in the world. The invasive plant is also planted very commonly along roadsides in Korea. In late October 2011 and August 2012, signs and symptoms of a powdery mildew disease were observed on lanceleaf coreopsis in several land areas near Gwangju-river, Gwangju, Korea. Symptoms included typical white superficial mycelia. The conidia of the powdery mildew fungus occurred on adaxial and abaxial surfaces. Chasmothecia were not observed. Single conidia formed terminally on conidiophores. Conidial morphology was subcylindrical to oblong. Dimension of conidia was 23.6 to 41.4 (avg. 35.1) μm long × 11.3 to 18.2 (avg. 14.8) μm wide. Conidiophores were composed of five to six (up to seven) cells, ranged from 45.7 to 131.2 (avg. 98.1) μm long × 8.2 to 11.1 (avg. 8.3) μm wide with foot-cells straight to slightly flexuous. Oidium anamorph of this fungus matched that of E. arcuata U. Braun, Heluta and S. Takam. described by Pastircakova et al. (3). From extracted genomic DNA, the rDNA ITS was amplified with ITS1F (5′-CTTGGTCATTTAGAGGAAGT-3′) and LR5F (5′-GCTATCCTGAGGGAAAC-3′) primer set. The rDNA ITS homology of the fungus (EML-CDPW1, GenBank Accession No. JX485650) showed 100% (590/590) identity value with E. arcuata (GenBank Accession No. AB252459). The identification of the fungus as E. arcuata was based on morphological data combined with the results of sequence analysis. Until recently, E. arcuata has been known to widespread on Carpinus species of the family Betulaceae including European hornbeam (C. betulus L.) and Chonowski's hornbeam (C. tschonoskii Maxim.) in Asia and Europe since Braun et al. first reported it as a new species in 2006 (1). In Korea, Podosphaera fusca (= Sphaerotheca fusca) and P. fuliginea (= S. fuliginea) were reported to cause powdery mildews on Coreopsis lanceolata. E. cichoracearum (= Golovinomyces cichoracearum), Leveillula taurica, P. fusca (= S. fusca), and Oidium spp. have been reported on Coreopsis spp. in the world (3). To our knowledge, this is the first report of powdery mildew caused by Oidium anamorph of E. arcuata on lanceleaf coreopsis (C. lanceolata) in Korea or elsewhere in the world. References: (1) U. Braun et al. Mycol. Prog. 5:139, 2006. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. http://nt.ars-grin.gov/fungaldatabases/ , 2012. (3) K. Pastircakova et al. J. Phytopathol. 156:597, 2008.

scholarly journals First Report of Powdery Mildew Caused by Golovinomyces artemisiae on Artemisia annua in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1010-1010
Author(s):  
J. K. Choi ◽  
B. S. Kim ◽  
I. Y. Choi ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
Powdery Mildew ◽  
Artemisia Annua ◽  
Russian Far East ◽  
Far East ◽  
Its Region ◽  
Hyphal Growth ◽  
Width Ratio ◽  
First Report ◽  
Powdery Mildews ◽  
Sweet Wormwood

Artemisia annua L., known as sweet wormwood or sweet annie, is native to temperate Asia, but is naturalized throughout the world. It produces artemisinin, a potent antimalarial drug that is also effective in treating other parasitic diseases (4). In August 2013, hundreds of plants showing typical symptoms of powdery mildew were found in Seoul (37°36′29.4″ N 127°02′38.3″ E), Korea. Powdery mildew colonies first appeared as thin white patches, which progressed to abundant hyphal growth on both sides of the leaves, stems, and inflorescence. As symptoms continued to develop, the leaves became distorted and turned purplish-gray. Severe infections caused leaf withering and premature senescence. The same symptoms were found on sweet wormwoods in Nonsan (36°09′55.3″ N 127°01′07.1″ E) and Chuncheon (37°52′27.4″ N 127°43′10.0″ E), Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were nipple-shaped or occasionally lobed. Conidiophores were cylindrical, measured 120 to 230 × 10 to 12.5 μm, and produced 2 to 4 immature conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells of conidiophores were straight, cylindrical, and 54 to 100 μm long. Conidia were hyaline, ellipsoid to barrel-shaped, measured 30 to 40 × 15 to 20 μm (length/width ratio of 1.5 to 2.1), lacked distinct fibrosin bodies, and showed reticulate wrinkling of the outer walls. Germ tubes were produced on the perihilar position of conidia. Primary conidia were apically rounded, basally subtruncate, and generally smaller than the secondary conidia. No chasmothecia were observed. The structures described above were typical of the powdery mildew Euoidium anamorph of the genus Golovinomyces, and the fungus measurements were similar to those of G. artemisiae (Grev.) V.P. Heluta (3). The complete internal transcribed spacer (ITS) region of rDNA from KUS-F27763 was amplified with primers ITS1/ITS4 and sequenced. The resulting sequence of 624 bp was deposited in GenBank (Accession No. KJ136112). The obtained ITS sequence shared >99% similarity with G. artemisiae on A. princeps and A. montana from Japan (AB077659 and AB077649) and A. argyi from China (KF056818). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy potted plants. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 5 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Powdery mildews of A. annua caused by G. artemisiae have been reported in Japan, China, the Russian Far East, and Romania (1,2). To our knowledge, this is the first report of powdery mildew caused by G. artemisiae on A. annua in Korea. Since sweet wormwood production was only recently started on a commercial scale in Korea, powdery mildew infections pose a serious threat to the production of this plant, especially in organic farming where chemical control options are limited. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. G. Fischer Verlag, Jena, 1995. (3) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (4) P. J. Weathers et al. Phytochem. Rev. 10:173, 2011.

scholarly journals First Report of Powdery Mildew on Trident Maple Caused by Sawadaea nankinensis in Korea

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1348-1348
Author(s):  
H. B. Lee ◽  
C. J. Kim ◽  
H. Y. Mun ◽  
J. P. Hong ◽  
D. A. Glawe
Keyword(s):  
Powdery Mildew ◽  
Its Region ◽  
Agricultural Science ◽  
Morphological Data ◽  
First Report ◽  
5.8S Rdna ◽  
Rdna Sequences ◽  
National University ◽  
Causal Fungus ◽  
Pathogenicity Tests

Trident maple (Acer buergerianum Miq.) is widely grown in Korea as an ornamental tree as well as for the art of bonsai. During 2008 and 2009, a powdery mildew was observed on trident maple plants at the campus of Chonnam National University, Gwangju, Korea. Further surveys revealed the disease to be widespread on this species in other areas including Jeonbuk and Chungnam provinces in Korea. White, superficial mycelia were observed on young shoots and leaves early in spring. Both macroconidia and microconidia were produced beginning in May and conidial production continued through the summer into September and October. Production of chasmothecia was observed starting in September and continued into October. Macroconidia were produced in chains that were sinuate in outline. Individual macroconidia were barrel shaped and 23.4 to 30.0 (26.6) × 15.6 to 21.1 (18.1) μm. Foot cells of macroconidial conidiophores were 26.7 to 110.7 (48) × 7.1 to 11.2 (8.8) μm with one to five following cells. Microconidia were broadly ellipsoidal to subglobose and 8.9 to 12.5 (10.5) × 4.3 to 5.8 (5.1) μm. Chasmothecia typically were formed on adaxial leaf surfaces and 193.2 to 238.1 (216.8) μm in diameter. Appendages bore uncinate to circinate apices and were 176.8 to 267.7 (211.5) × 4.3 to 8.0 (6.2) μm. From extracted genomic DNA, internal transcribed spacer (ITS) region inclusive of 5.8S rDNA was amplified with ITS1F (5′-CTTGGTCATTTAGAGGAAGT-3′) and LR5F (5′-GCTATCCTGAGGGAAAC-3′) primers. The causal fungus was determined to be Sawadaea nankinensis (F.L. Tai) S. Takam. & U. Braun (2) on the basis of morphological data and ITS rDNA sequences. A BLAST search of GenBank with an ITS sequence from this fungus determined that the five sequences exhibiting the highest max score values (1,811 to 2,004) were from S. nankinensis; these sequences produced max ident values from 94% to 99%. In contrast, max score and max ident values from sequences of other Sawadaea spp. were lower, including scores of 1,063 and 98% similarity for S. polyfida var. japonica, 915 and 97% for S. tulasnei, and 913 and 97% for S. bicornis. Pathogenicity tests were conducted on field-grown plants in two replicates. These plants were inoculated with a paintbrush to apply conidia (~5 × 106/ml) collected from powdery-mildew-infected leaves. Inoculated plants developed powdery mildew symptoms within 5 days of inoculation and resembled those observed on naturally infected plants. S. nankinensis (synonym Uncinula nankinensis) was first reported on A. buergerianum from China in 1930 (2). Recently, S. nankinensis (F.L. Tai) S. Takam & U. Braun was reported to occur on A. buergerianum in Japan (3). Until now, three Sawadaea spp. (S. bicornis (Wallr.) Homma, S. negundinis Homma, and S. tulasnei (Fuckel) Homma) have been reported to cause powdery mildew on A. ginnala, but only S. bicornis (= U. circinata Cooke & Peck) has been reported to cause powdery mildew on A. ginnala in Korea (1). However, no Sawadaea sp. previously was reported to cause powdery mildew on A. buergerianum. To our knowledge, this is the first report of powdery mildew on trident maple (A. buergerianum) caused by S. nankinensis in Korea. References: (1) H. D. Shin. Erysiphaceae of Korea. National Institute of Agricultural Science and Technology, 2000. (2) F. L. Tai. Page 1517 in: Sylloge Fungorum Sinicorum. Science Press, Academia Sinica, Peking, 1979. (3) S. Takamatsu et al. Mycoscience 49:161, 2008.

scholarly journals Trichothecium roseum Causes Fruit Rot of Tomato, Orange, and Apple in Pakistan

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1271-1271 ◽  
Author(s):  
M. I. Hamid ◽  
M. Hussain ◽  
M. U. Ghazanfar ◽  
M. Raza ◽  
X. Z. Liu
Keyword(s):  
Sequence Analysis ◽  
Its Region ◽  
Molecular Techniques ◽  
Fruit Rot ◽  
Control Treatment ◽  
Distilled Water ◽  
Trichothecium Roseum ◽  
Fruit Samples ◽  
The World ◽  
Stereo Microscope

During a field survey of greenhouses and fresh markets in 2013, fruits of tomato, oranges, and apples exhibited rot symptoms with white mycelial growth and salmon-color sporulation in the vicinity of Sargodha city (32°5′1″ N, 72°40′16″ E), Pakistan. Diseased fruit samples were collected in plastic bags and taken to laboratory on ice for further diagnosis. Diseased fruits were observed under a stereo microscope and single spores were removed using an inoculating needle. Isolation from single spores showed pink to white colonies on potato dextrose agar (PDA) containing hyaline, 2-celled, ellipsoid to pyriform conidia (17 to 24 × 7 to 11 μm) with slanting and truncate basal mark and produced in clusters. Conidiophores were branched (105 to 254 × 2 to 4 μm) and hyphae were hyaline (3 to 5 μm in diameter). These characteristics of the fungus were similar to Trichothecium roseum (Pers.) as reported by Inácio et al. (1). Genomic DNA was extracted by using CTAB buffer from a single pure colony of one isolate of the fungus and PCR analysis was performed for ITS region and part of the 5′ end of the beta tubulin (TUB) gene (2,3). Single fragments of 550 bp and 1.5 kb length from ITS and TUB gene were amplified and sequenced (GenBank Accession Nos. KF975702 and KJ607590, respectively). Sequence analysis showed 99% similarity with T. roseum isolates from different regions of the world. Phylogenetic analysis (MEGA version 5.2 with WAG model) showed the close relatedness to the isolates of T. roseum from Pakistan and isolates from other parts of the world that revealed the low genetic variability of ITS region. TUB gene sequence analysis indicated 100% homology with isolates of T. roseum and to the other species in Hypocreales. Pathogenicity tests were performed on tomato cvs. Nova Mech and Rio Grande, orange cv. Kinnow, and on apple cv. Golden Delicious by inoculating five fruits from each cultivar. Spore suspensions (105 conidia/ml of sterilized distilled water) were inoculated into all wounded fruits (9 wounds/fruit) of each cultivar and incubated at 25°C for the development of symptoms. Five wounded fruits of each cultivar were inoculated with sterilized distilled water as a control treatment. The fruits were kept in plastic boxes and incubated in humid chambers for 5 days. The symptoms on apples were observed as brown rot with pinkish spores on rotted tissue. The cross section of apple fruits also showed the brown rotted tissues internally. The fungus developed mycelium and spores on the surface and caused severe rotting inside the tomato and citrus fruits. T. roseum was re-isolated by picking a single spore from rotted tissues of fruits under a stereo microscope, and culturing on PDA. The re-isolated fungus was confirmed morphologically and by molecular techniques. Tomato and apple has been reported as a host for T. roseum (1,4,5) but oranges have not. To our knowledge, this is the first record of T. roseum infecting tomato, oranges, and apples in Pakistan. References: (1) C. A. Inácio et al. Plant Dis. 95:1318. 2011. (2) K. O'Donnell, and E. Cigelnik. Mol. Phylogenet. Evol. 7:103, 1997. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (4) Y. H. Yun et al. Afr. J. Microbiol. Res. 7:1128, 2013. (5) M. Žabka et al. Mycopathologia. 162:65, 2006.

scholarly journals First Report of Powdery Mildew Caused by Podosphaera xanthii on Cucurbita argyrosperma in Mexico

Plant Disease ◽  
2021 ◽  
Author(s):  
José Francisco Díaz-Nájera ◽  
Sergio Ayvar-Serna ◽  
Antonio Mena-Bahena ◽  
Guadalupe Arlene Mora-Romero ◽  
Karla Yeriana Leyva-Madrigal ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Microscopic Examination ◽  
Disease Incidence ◽  
Phylogenetic Analyses ◽  
Its Region ◽  
Likelihood Method ◽  
28S Rrna ◽  
Podosphaera Xanthii ◽  
Voucher Specimen ◽  
First Report

Cucurbita argyrosperma, commonly named as winter or cushaw squash, is highly sought for its seeds, which have important uses in culinary arts. During the autumn 2021, powdery mildew-like signs and symptoms were observed on cushaw squash in several commercial fields located in Cocula, Guerrero, Mexico. Signs were initially appeared as whitish powdery patches on both sides of leaves and then covering entire leaves and causing premature senescence. The disease incidence was estimated to be 80% in about 1000 plants in two fields. The mycelium was amphigenous, persistent, white in color, and occurred in dense patches. A voucher specimen was deposited in the Herbarium of the Colegio Superior Agropecuario del Estado de Guerrero under the accession number CSAEG22. For the morphological characterization by light microscopy, fungal structures were mounted in a drop of lactic acid on a glass slide. Microscopic examination showed nipple-shaped hyphal appressoria. Conidiophores (n = 30) were straight, 100 to 190 × 10 to 12 μm and produced 2 to 6 conidia in chains. Foot-cells were cylindrical, 41 to 78 μm long, followed by 1 to 2 shorter cells. Conidia (n = 100) were ellipsoid-ovoid to barrel-shaped, 29.5 to 39.1 × 19.4 to 22.7 μm, and contained conspicuous fibrosin bodies. Germ tubes were produced from a lateral position on conidia. Chasmothecia were not observed during the growing season. The morphological characters were consistent with those of the anamorphic state of Podosphaera xanthii (Braun and Cook 2012). For further confirmation, total DNA was extracted from conidia and mycelia following the CTAB method (Doyle and Doyle 1990), and the internal transcribed spacer (ITS) region and part of the 28S gene were amplified by PCR, and sequenced. The ITS region of rDNA was amplified using the primers ITS5/ITS4 (White et al. 1990). For amplification of the 28S rRNA partial gene, a nested PCR was performed using the primer sets PM3 (Takamatsu and Kano 2001)/TW14 (Mori et al. 2000) and NL1/TW14 (Mori et al. 2000) for the first and second reactions, respectively. Phylogenetic analyses using the Maximum Likelihood method, including ITS and 28S sequences of isolates of Podosphaera spp. were performed and confirmed the results obtained in the morphological analysis. The isolate CSAEG22 grouped in a clade with isolates of Podosphaera xanthii. The ITS and 28S sequences were deposited in GenBank under accession numbers OL423329 and OL423343, respectively. Pathogenicity was confirmed by gently dusting conidia from infected leaves onto ten leaves of healthy C. argyrosperma plants. Five non-inoculated leaves served as controls. The plants were maintained in a greenhouse at 25 to 35 ºC, and relative humidity of 60 to 70%. All inoculated leaves developed similar signs to the original observation after 10 days, whereas control leaves remained symptomless. Microscopic examination of the fungus on inoculated leaves showed that it was morphologically identical to that originally observed on diseased plants, fulfilling Koch’s postulates. Podosphaera xanthii has been previously reported on C. maxima, C. moschata, and C. pepo in Mexico (Yañez-Morales et al. 2009; Farr and Rossman 2021). To our knowledge, this is the first report of P. xanthii causing powdery mildew on C. argyrosperma in Mexico. This pathogen is a serious threat to C. argyrosperma production in Mexico and disease management strategies should be developed.

scholarly journals First Report of Powdery Mildew Caused by Erysiphe macleayae on Macleaya microcarpa in Poland

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1376-1376 ◽  
Author(s):  
M. J. Park ◽  
S. E. Cho ◽  
M. Piątek ◽  
H. D. Shin
Keyword(s):  
Powdery Mildew ◽  
Sequence Similarity ◽  
Signs And Symptoms ◽  
Its Region ◽  
Botanical Garden ◽  
Central China ◽  
Perennial Herb ◽  
Width Ratio ◽  
First Report ◽  
Potted Plants

Macleaya microcarpa (Maxim.) Fedde, also known as smallfruit plume poppy, is a perennial herb belonging to the family Papaveraceae. The plant, together with the better-known species M. cordata (Willd.) R. Br., is native to central China and is now planted worldwide for medicinal purposes. In October 2008 and August 2009, dozens of smallfruit plume poppy planted in the Kraków Botanical Garden, Poland, were found to be severely infected with a powdery mildew. White colonies with abundant sporulation developed on both sides of leaves and young stems, forming circular to irregular patches. Infections caused leaf yellowing and premature defoliation. The damage has been observed every year since 2009. Representative voucher specimens were deposited in the fungal herbarium of the W. Szafer Institute of Botany of the Polish Academy of Sciences (KRAM) and the Korea University herbarium (KUS). Appressoria on the mycelia were lobed, often in pairs. Conidiophores composed of three to four cells arose from the upper part of creeping hyphae, 65 to 120 × 7 to 10 μm, attenuated toward the base, sub-straight or slightly flexuous in foot-cells, and produced conidia singly. Conidia were hyaline, oblong-elliptical to doliiform, 25 to 38 × 12 to 18 μm with a length/width ratio of 1.8 to 2.6; lacked fibrosin bodies; and produced germ tubes on the subterminal position with club-shaped or lobed appressoria. The conidial surface was wrinkled to irregularly reticulate. No chasmothecia were found. The structures described above match well with the anamorph of Erysiphe macleayae R.Y. Zheng & G.Q. Chen (3). To confirm the identity of the causal fungus, the internal transcribed spacer (ITS) region of rDNA from KUS-F24459 was amplified using primers ITS5 and P3 (4) and directly sequenced. The resulting sequence of 553 bp was deposited in GenBank (Accession No. JQ681217). A GenBank BLAST search using the present data revealed >99% sequence similarity of the isolate with E. macleayae on M. cordata from Japan (AB016048). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants. Three noninoculated plants served as controls. Plants were maintained in a greenhouse at 25°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants. The powdery mildew infections of M. cordata associated with E. macleayae have been recorded in China and Japan (2), and more recently in Germany (1,3). To our knowledge, this is the first report of E. macleayae on M. microcarpa globally as well as in Poland. This mildew species was described in China and is endemic to Asia, where chasmothecia of the fungus were found. Only recently have powdery mildews been found on M. cordata in Germany (1,3) and now on M. microcarpa in Poland, indicating the fungus is spreading in Europe. References: (1) N. Ale-Agha et al. Schlechtendalia 17:39, 2008. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , February 7, 2012. (3) A. Schmidt and M. Scholler. Mycotaxon 115:287, 2011. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

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