First Report of Anthracnose on Cinnamomum camphora (Camphor tree) Caused by Colletotrichum fioriniae and Colletotrichum siamense in China

Camphor tree (Cinnamomum camphora) is native to east Asia, which could produce pharmaceutical metabolites, such as camphor, linalool, and so on (Chen, Tang et al. 2020). In September 2020, severe anthracnose symptoms were observed on the leaves of camphor trees in Nanchang, and estimated incidences ranged from 30% to 80%, which could inhibit leaf growth and reduce their biomass. The lesions were appeared on the leaves of annual branchlets, which the irregular dead areas appeared on leaf tips or margins (Figure 1 A and B), sometimes moving onto the shoots and small twigs. For pathogen isolation, fifteen leaves with typical symptom were randomly collected in Jiangxi Agricultural University (N28°45'38", E115°50'0.006") and the fungi were isolated from the symptomatic-asymptomatic junction and cultured on potato dextrose agar (PDA) at 25℃ in darkness. A total of 40 isolates were obtained from tissue samples, in which 32 isolates were identified as belonging to Colletotrichum spp. following the published works (Damm, Cannon et al. 2012, Damm, Cannon et al. 2012, Weir, Johnston et al. 2012). Based on the morphologies of conidia, all the 32 isolates were classified into two categories. For further precise identification, the represented isolate YK1 and YK18 were selected to analyzed using morphological characters after 7 days of incubation, and multiple genes including ITS (White, Bruns et al. 1990), ACT, GAPDH, TUB (Damm, Woudenberg et al. 2009) and RPB2 (Réblová, Gams et al. 2011). Sequences were deposited in GenBank with accession numbers from MZ229311 to MZ229326. Conidia of isolate YK1 were aseptate, primarily fusiform and measured 14.07-21.21 µm × 4.99-6.79 µm (n = 51) (Figure 1 L) and acervulus were 60.24 to 113.56 µm × 44.24 to 102.63 µm (n = 6) (Figure 1 K), while that of YK18 were one-celled, cylindric with obtuse ends (Figure 1 N) and measured 13.28-16.51 µm × 4.10-5.82 µm (n = 52) and acervulus were 73.85 to 131.70 µm × 63.93 to 105.66 µm (n = 6) (Figure 1 M). Acervulus of isolate YK1 and YK18 were produced on alfalfa stems 40 days after inoculation and dark brown to black in color. For all the genes showed greater than 99% similarity to multiple C. fioriniae and C. siamense accessions, respectively. The phylogram reconstructed from the combined dataset using W-IQ-TREE (Trifinopoulos, Nguyen et al. 2016) showed that isolate YK1 and YK18 clustered with C. fioriniae and C. siamense, respectively. Pathogenicity of both species was tested in the field by ten inoculating surface-sterilized mature leaves with puncture wound (Figure 1 C and D) and ten non-wounded young leaves with 20 µL of a conidial suspension (105 conidia ml-1) (Figure F and G). Leaves treated with sterilized water under the same conditions served as controls. After 4 to 7 days, the inoculated leaves of camphor tree developed typical dark brown to black lesions, similar to symptoms observed in the field, whereas controls remained symptomless. To fill the Koch’s postulates, C. fioriniae and C. siamense were consistently re-isolated, and confirmed morphologically and molecularly. C. siamense have been found to cause anthracnose on Cinnamomum camphora in China (Xu, 2017). To our knowledge, this is the first report of anthracnose on Cinnamomum camphora with C. fioriniae in China. In addition, this is an indication to the complexes about pathogens to anthracnose on camphor tree, which can pose serious threat to the production of Cinnamomum camphora in China.

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First Report of Leaf Spot Disease on Cinnamomum camphora (Camphor tree) Caused by Epicoccum poaceicola in China

Plant Disease ◽

10.1094/pdis-04-21-0683-pdn ◽

2021 ◽

Author(s):

Da Li ◽

Tianning Zhang ◽

Qingni Song ◽

Jun Liu ◽

Haiyan Zhang ◽

...

Keyword(s):

Leaf Spot ◽

Leaf Growth ◽

Leaf Spot Disease ◽

Molecular Characteristics ◽

Post Inoculation ◽

Cinnamomum Camphora ◽

First Report ◽

Spot Disease ◽

Leaf Spots ◽

Camphor Tree

As an important industrial, pharmaceutical and evergreen shade tree (Singh and Jawaid 2012), the camphor tree (Cinnamomum camphora) has been coppiced in Jiangxi Province, China. From 2017 to 2020, we noticed many camphor trees with leaf spots, with an incidence estimated at 50 to 75%, which could severely inhibit leaf growth and reduce their biomass. A dark-green circle with a watery spot appeared on the infected leaves at the initial stage, and necrosis with forming shot-spots surrounded by yellow halos occurred (Figure 1 A). Five leaves with typical symptoms were sampled and washed with tap water for ca. 15 min. Isolation and morphological analysis were performed following the method of Bao et al. (2019). Among 61 fungal isolates, 49 showed the same culture characters. Colonies on PDA were villose and regular, the reverse was scarlet at the edge of the colony, which was ca. 8.75 cm after 7 days of inoculation (Figure 1 I). Chlamydospores were aseptate, dark brown, smooth, in chains or solitary, ellipsoidal to ovoid, 4.8–9.6 × 4.8–11.1 μm (Figure 1 J). The pycnidia were produced on PDA and varied from 47.4 to 85.8 µm (mean 60.2 µm) × 38.6 to 66.8 μm (mean 49.7 μm) (n = 17) (Figure 1 K). Conidia were hyaline, unicellular, elliptical to ovoid, 4.3-6.4 µm (mean 5.1 µm) × 2.3-3.3 µm (mean 2.8 µm) (n = 52) (Figure 1 L). Pathogenicity tests of isolate XW-9 was carried out in the field. Ten leaves were wounded with a sterilized insect needle and inoculated with mycelium plugs (7-mm diameter). Non-colonized PDA plugs served as the negative controlIn addition, conidial suspensions (105 conidia/mL) of isolate XW-9 were sprayed on surface-sterilized leaves with a further ten leaves being sprayed with sterile water as the control. Symptoms described in this study appeared in 100% of the mycelium-inoculated leaves and more than 80% of the conidium-inoculated leaves after 7 days post-inoculation (Figure 1 B-E). No symptoms were seen in the controls (Figure 1 C). Three days after inoculation, brown spots resembling those observed in the field developed on the inoculated leaves, and some lesions turned into shot holes on the infected leaves (Figure 1 G & H). However, no symptoms were observed on the controls (Figure 1 F). The fungus was re-isolated from the margins of the leaf spots and labelled P-XW-9A. The gene regions for ITS, LSU, tub2, RPB2 and ACT of isolates XW-9 and P-XW-9A were amplified and sequenced. The sequences of rDNA-ITS, LSU, tub2, RPB2 and ACT of XW-9 were GenBank MW142397, MW130844, MW165322, MW446945 and MW165324, respectively and those of P-XW-9A were GenBank MW142398, MW130845, MW165323, MW446946 and MW165325, respectively (Lumbsch, et al. 2000; Aveskamp, et al. 2009; Hou et al. 2020). Phylogenetic analysis using concatenated sequences of ITS, LSU, RPB2, and tub2 showed that isolates XW-9 and P-XW-9A formed a single clade with the reference strain of E. poaceicola CBS 987.95 (Figure 2). Thus, XW-9 was identified as E. poaceicola based on its morphological and molecular characteristics. Significantly, the recovered isolate P-XW-9A also aligned with E. poaceicola fulfilling the criteria for Koch's Postulates. E. poaceicola was only reported as a fungal pathogen of Phyllostachys viridis in China (Liu et al. 2020). To our knowledge, this is the first report of leaf spot disease on camphor trees caused by E. poaceicola in China and our findings will be useful for its management.

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First Report of Fusarium Blight on Majesty Palm Caused by Fusarium proliferatum in Italy

Plant Disease ◽

10.1094/pdis.2003.87.9.1149a ◽

2003 ◽

Vol 87 (9) ◽

pp. 1149-1149 ◽

Cited By ~ 6

Author(s):

G. Polizzi ◽

A. Vitale

Keyword(s):

Fusarium Proliferatum ◽

Conidial Suspension ◽

First Report ◽

Leaf Spots ◽

Initial Symptoms ◽

Mt Etna ◽

Young Leaves ◽

Pure Cultures ◽

Severe Infections ◽

Fusarium Sp

During spring 2002, a new disease of majesty palm (Ravenea rivularis Jumelle & H. Perrier) was observed on young, container-grown plants (3 to 4 years old with five to seven expanded leaves) in a nursery in eastern Sicily. Initial symptoms on the youngest, expanded leaves and especially on the unopened, spear leaves were small, reddish-brown necrotic lesions (2 to 4 mm in diameter) with a yellow halo. In high humidity, lesions increased in size and number, coalescing into large, irregular dead areas. These symptoms developed into blights of the youngest, unopened leaves. As a consequence, infected leaves would dieback and only a few plants recovered from these severe infections. On the surviving plants, reddish-brown necrotic lesions appeared on the rachis. From these lesions, 30 pieces of tissue were cut, surface sterilized (30 s in 1.2% wt/vol of NaOCl), washed with sterile water, and plated on potato dextrose agar supplemented with 1.1 μl/ml of lactic acid (stock 88 to 92%) (A-PDA). Conidia and conidiophores were collected directly from the tissue with a flamed needle and placed on A-PDA. Fusarium sp. was consistently isolated from the necrotic tissue, and after 3 days, single hyphal tips were transferred to pure cultures from which were obtained two single, conidial isolates. These fungal isolates were forwarded to the CABI Bioscience U.K. Centre, Bakeham Lane (Egham), Surrey, U.K., where both isolates were identified as Fusarium proliferatum (T. Matsushima) Nirenberg. A morpho-biometrical characterization was performed on carnation leaf agar with a photoperiod of 10 h. Macroconidia were slender, lightly falcate to almost straight, 3- to 5-septate, and ranged from 37 to 53 × 2.5 to 3 μm (average 44.1 × 2.8 μm). Microconidia, clavate or oval with a truncated base, were formed in chains from mono- or polyphialides. Chlamydospores were absent. Eight 2-year-old seedlings (three to five expanded leaves) of majesty palm had the unopened spear leaves needle-wounded and another eight were unwounded. All were sprayed with a conidial suspension (1.5 × 106 CFU/ml). An equal number of noninoculated plants were used as a control. All plants were covered with polyethylene bags and incubated in a greenhouse at 25 ± 2°C for 72 h. All wounded majesty palms showed brown areas on unopened spear leaves. When natural injures were present, reddish leaf spots appeared as early as 4 days after inoculation. Macroscopic observations revealed the presence of white mycelium on the necrotic areas and reddish spots. Koch's postulates were satisfied by reisolation of the fungus on A-PDA from artificially infected tissues. On the basis of 3 months of field observations in Sicily, spread of Fusarium blight on majesty palm was always greater when plants were injured on the tender and unopened leaves by volcanic cinders from Mt. Etna, which caused bruises on young leaves. The disease does not represent a major threat to nurseries, but it could cause loss in the cultivation of the majesty palm. F. proliferatum was previously recorded in Saudi Arabia as the causal agent of wilt and dieback of date palm (1). To our knowledge, this is the first report of F. proliferatum on palms in Italy and the first outbreak of the disease on majesty palm. Reference: (1)M. Y. Abdalla et al. Plant Dis. 84:321, 2000.

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First Report of Anthracnose Caused by Colletotrichum dematium on Statice (Goniolimon tataricum, Synonym Limonium tataricum) in Bulgaria

Plant Disease ◽

10.1094/pdis-93-5-0552c ◽

2009 ◽

Vol 93 (5) ◽

pp. 552-552 ◽

Cited By ~ 2

Author(s):

S. G. Bobev ◽

Z. J. Jelev ◽

A. Zveibil ◽

M. Maymon ◽

S. Freeman

Keyword(s):

Leaf Age ◽

Morphological Characters ◽

Field Conditions ◽

Conidial Suspension ◽

Internal Transcribed Spacer Region ◽

Factors Affecting ◽

First Report ◽

Colletotrichum Dematium ◽

Humidity Chamber ◽

Ornamental Species

German statice (Goniolimon tataricum, synonym Limonium tataricum) is a popular ornamental species, which is frequently used in bouquet arrangements. During a field survey of statice farms in the Plovdiv Region of Bulgaria (August 2007), lesions were observed predominantly on the peduncles and rarely on wilted leaves of 2- and 3-year-old plants. Symptoms appeared on the base of peduncles as irregular, brown necrotic lesions ranging from 30 to 40 mm that coalesced, whereas lesions on leaves were initially round to elliptical with dimensions from 5 to 15 mm and developed a necrosis that subsequently spread toward the petioles. Rounded and elongated setose acervuli were observed on the lesions of peduncles. Isolations on potato dextrose agar (PDA) produced fungal colonies that initially were whitish but turned gray 4 to 5 days after incubation at 25°C. Falcate, hyaline, and aseptate conidia with mean dimensions of 22.0 × 4.5 μm, ranging from 18.3 to 25.0 × 4.2 to 5.8 μm, were observed from acervuli of both naturally infected peduncles and PDA-cultured colonies. Pathogenicity of the fungus (three single-conidium representative isolates) was tested by spray inoculating 4-month-old intact plantlets (12 to 15 fully developed leaf stage) with a conidial suspension (106 conidia/ml, 15 ml/plant) and maintaining them in a humidity chamber for 30 h. Plants sprayed with sterile water served as controls. There were three replicates per treatment per isolate and the experiment was conducted twice at room temperature (22 to 26°C). After 10 to 12 days, the spray-inoculated plants exhibited light brown lesions mainly on the older leaves that gradually expanded and caused leaf mortality. The pathogen was reisolated from all inoculated samples but not from any of the control and symptomless treatments, thus fulfilling Koch's postulates. It should be noted that symptoms caused by the pathogen in artificially inoculated plants were seen as wilting of petioles and leaves, as opposed to necrotic lesions observed on leaves under field conditions. This may be related to the method of inoculation, leaf age, and texture, as well as environmental factors affecting symptomology under natural field conditions. Sequence analysis of the rDNA internal transcribed spacer region of three representative isolates (GenBank Accession Nos. FJ236461–FJ236463) showed the fungus to be 99% similar to an isolate of Colletotrichum dematium (GenBank Accession No. AJ301954), consistent with the observed morphological characters. On the basis of observed symptoms, morphology, and molecular characterization, it can be concluded that C. dematium is the causal agent of anthracnose of German statice in Bulgaria. To our knowledge, this is the first report of this pathogen on G. tataricum in Bulgaria, although it has been reported that C. dematium (1) and C. gloeosporioides (1–3) may attack other Limonium species. References: (1) C. F. Hong et al. Plant Pathol. Bull. 15:241, 2006. (2) T. Kagiwata. J. Agric. Sci. (Jpn.) 31:101, 1986. (3) M. Maymon et al. Phytopathology 96:542, 2006.

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First Report of Leaf Blight on Rubus brasiliensis Caused by Colletotrichum acutatum in Brazil

Plant Disease ◽

10.1094/pdis-06-10-0441 ◽

2010 ◽

Vol 94 (11) ◽

pp. 1378-1378 ◽

Cited By ~ 1

Author(s):

U. P. Lopes ◽

L. Zambolim ◽

H. S. S. Duarte ◽

P. G. C. Cabral ◽

O. L. Pereira ◽

...

Keyword(s):

Native Species ◽

Morphological Characteristics ◽

Minas Gerais ◽

Leaf Blight ◽

Colletotrichum Acutatum ◽

Conidial Suspension ◽

Specific Primer ◽

First Report ◽

Young Leaves ◽

Necrotic Spots

There are more than 300 blackberry (Rubus) species worldwide. Rubus brasiliensis Mart. is a native Brazilian species found in tropical forests. In January 2009, samples of R. brasiliensis with severe leaf blight were collected from an area of rain forest in the city of São Miguel do Anta, State of Minas Gerais, Brazil. Dark spots began developing in the young leaves and progressed to necrotic spots with occasional twig dieback. From the spots, a fungus was isolated with the following morphology: acervuli that were 20 to 50.0 × 50 to 125.0 μm and hyaline amerospores that were ellipsoid and fusiform and 7.5 to 23.75 × 2.5 to 5.0 μm. On the basis of these morphological characteristics, the fungus was identified as Colletotrichum acutatum. In Brazil, C. acutatum is reported in apple, citrus, strawberry, peach, plum, nectarine, olive, medlar, and yerba-mate, but it was not reported as the causal agent of leaf blight in R. brasiliensis. A sample was deposited in the herbarium at the Universidade Federal de Viçosa, Minas Gerais, Brazil (VIC 31210). One representative isolate, OLP 571, was used for pathogenicity testing and molecular studies. Identity was confirmed by amplifying the internal transcribed spacer (ITS) regions of the ribosomal RNA with primers ITS4 (3), CaInt2 (a specific primer for C. acutatum [2]) and CgInt (a specific primer for C. gloeosporioides [1]). Isolates of C. acutatum (DAR78874 and DAR78876) and C. gloeosporioides (DAR78875) obtained from Australian olive trees were used as positive controls. The primers ITS4 and CaInt2 amplified a single DNA product of 500 bp expected for C. acutatum. OLP 571 was grown for 7 days on potato dextrose agar. Young leaves of R. brasiliensis were inoculated with a conidial suspension (106 conidia/ml) on young leaves. Inoculated plants were maintained in a moist chamber for 2 days and subsequently in a greenhouse at 25°C. Necrotic spots similar to those described were detected on young leaves 3 days after the inoculation. Control leaves, on which only water was sprayed, remained healthy. The same fungus was reisolated from the inoculated symptomatic tissues. To our knowledge, this is the first report of C. acutatum causing leaf blight in the native species of R. brasiliensis in Brazil. References: (1) P. R. Mills et al. FEMS Microbiol. Lett. 98:137, 1999. (2) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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First report of Diaporthe eres causing branch canker on Cinnamomum camphora (camphor tree) in Jiangxi Province, China

Plant Disease ◽

10.1094/pdis-10-20-2306-pdn ◽

2021 ◽

Author(s):

Da Li ◽

Haiyan Zhang ◽

Qingni Song ◽

Jun Liu ◽

Qingpei Yang ◽

...

Keyword(s):

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Field Tests ◽

Jiangxi Province ◽

Pathogenicity Test ◽

Cinnamomum Camphora ◽

Phylogenetic Tree Analysis ◽

First Report ◽

Branch Dieback ◽

Camphor Tree

In September 2019, approximately 75 to 90% of camphor trees (Cinnamomum camphora) were observed with cankers and branch dieback symptoms in Anyi (N28°32’54’’, E115°37’52’’) and Xinyu (N27°37’38’’, E114°50’25’’) county (Jiangxi Province, China). The symptoms included dark brown to dark, oval-shaped canker lesions, sunken and cracked longitudinally, cracked and evenly swelling, or reddish brown (Figure 1 A-D). Samples were collected from symptomatic branches and were cut into small pieces (ca. 0.5 cm × 0.5 cm × 0.5 cm). Sections were surface sterilized as described by Zhang et al. (2020), then placed on potato dextrose agar amended with 0.01% penicillin and 0.015% streptomycin sulfate and incubated in the laboratory at 25℃ with darkness. After 3 to 5 days, mycelium growing out from tissues were transferred onto PDA medium. In total, 68 fungal isolates including 22 isolates of Diaporthe sp. were obtained from cankers and then were classified into five categories based on morphological characteristics and sequencing of the ITS for morphological representative strains. Pathogenicity tests were conducted in the greenhouse (Figure 1 E-M) and field (Figure 1 N-Q). Branches were surface sterilized and inoculated as described by Prencipe et al. (2017). In the greenhouse, a total of 13 representative isolates (including 6 isolates of Diaporthe sp., 2 isolates of Neofusicoccum sp., 2 isolates of Botryosphaeria sp. and 3 isolates of Colletotrichum sp.) were selected and evaluated using 2-year-old seedlings of camphor tree in pots with 5 replicates per isolate, in which 3 isolates of Collectotrichum sp. had no pathogenicity. Then, two isolates of Diaporthe sp. (Z4 and Z7) were selected for field experiment. In field tests, the same method was used as in the greenhouse. The inoculated and control branches were collected 40 days after inoculation and the fungi were isolated and placed on PDA plates to recover the inoculated fungi and complete Koch’s postulates. Both isolates of Diaporthe sp. produced canker symptoms on the branches. Isolate Z4 caused discoloration also on the branch without wounding. Both isolates produced pycnidia scattered in PDA plates supplemented with stems of alfalfa, were dark brown to black, globose to subglobose (Figure 1 T). Alpha conidia were cylindrical, 5.72-9.98 µm (mean 7.64 µm) × 2.15-3.13 µm (mean 2.69 µm) (n = 30) (Figure 1 S, red arrow), while beta conidia were biguttulate, one-celled, hyaline, non-septate, and 16.21-25.52 µm (mean 21.60 µm) × 0.76~1.65 µm (mean 1.14 µm) (n = 30, green arrow) (Figure 1 S). Five isolates (Z4, S-Z4, P-Z4, Z7 and S-Z7) including those used for pathogenicity test were selected for multi-locus phylogenetic analyses of ITS (White et al., 1990), TEF1-α and TUB2 (Glass et al. 1995) gene sequences, which the accession number was MW036358- MW036362 for ITS, MW052267- MW052271 for TEF1- α, MW052276-MW052280 for TUB2. Based on the phylogenetic tree analysis using IQ-TREE 2, all five isolates were identified as D. eres (Figure 2). D. eres has been reported to cause canker on many different woody plants, such as almond (Holland et al. 2020), peach (Prencipe et al. 2017), hazelnut (Wiman et al. 2019), and so on. However, this is the first report worldwide of D. eres causing disease on Cinnamomum camphora in China.

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First report of Mochi tree (Ilex integra) Anthracnose caused by Colletotrichum fioriniae in Korea

Plant Disease ◽

10.1094/pdis-07-20-1559-pdn ◽

2020 ◽

Author(s):

Jihye Woo ◽

Jeong Eun Kim ◽

Mikyeong Kim ◽

Byeongjin Cha

Keyword(s):

South Korea ◽

Seed Quality ◽

Pathogenicity Test ◽

Conidial Suspension ◽

First Report ◽

Mature Leaves ◽

Eastern Usa ◽

Young Leaves ◽

Symptomatic Tissue ◽

And Control

Ilex integra, also called Mochi tree, is an woody ornamental common in Asia, particularly in Korea, China, Japan, and Taiwan. Anthracnose, caused by Colletotrichum spp., is an economically important disease worldwide, affecting both fruit and seed quality. In April 2019, symptoms of Anthracnose were observed on leaves from several Mochi trees in an urban planting in Wando-gun, South Korea. Irregularly shaped, light-to-dark brown spots of 1-4mm were observed on young leaves. The lesions coalesced as each spot enlarged, flat and black fruiting bodies (acervuli) occurred on the brown lesions. Four symptomatic leaves were collected; fractions were cut from symptomatic tissue, including healthy tissue, then were disinfected with 1% sodium hypochlorite and 70% ethanol, and placed on potato dextrose agar (PDA). After dark-incubation at 25℃ for 7 days two isolates were obtained, the fungal colonies appeared as white to light gray mycelium, then becoming dark and orange to pink on the underside. After acervuli were produced on the plate, orange-red conidial masses erupted. Conidia observed from two isolates were hyaline, 1-celled, and oblong with round to acute apices, and measured 7 to 12 × 2 to 5 μm (mean ± SD: 9.29 ±2.26 × 3.68± 1.31 μm) (n=30). Genomic DNA was extracted and multi-locus sequencing was performed with one representative isolate using the internal transcribed spacer (ITS) (White et al. 1990), actin (ACT) genes, chitin synthase 1 gene (CHS-1) (Carbone and Kohn 1999), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Calmodulin (CAL) (Weir et al. 2012) and submitted. Blast search results showed that the isolate had 100%, 98.45%, 99.74%, 100%, and 100% nucleotide sequence identity with those of C. fioriniae (MT607651, MH717601, MG666441, MN895544, MN974144) respectively (Jamin and Mateu 2008). The five sequences were deposited in NCBI GenBank (Accession No: MT457472, MT465884, MT465885, MT465886, MT465887), which were assigned to ITS, ACT, CHS-1, GAPDH, and CAL regions, respectively. Based on the morphology (Shivas and Tan 2009) and molecular characterization (Guerber et al. 2003), the isolate was identified as C. fioriniae. To confirm pathogenicity, a conidial suspension (10⁶ conidia/ml) of the sequenced isolate was used to inoculated, young and mature leaves of a 4-year-old Mochi tree. Ten leaves of the seedling were disinfected with 70% ethanol, then were wounded with a toothpick. The conidial suspension (20 µl) was placed on the wound. The inoculated plant and control plants were tested with sterilized water and incubated at 25℃ in a moist chamber. The pathogenicity test was repeated three times. Typical spots were observed on the young leaves 2 days after inoculation, whereas they were observed on the mature leaves 7 days after inoculation. Acervuli developed on both young and mature leaves 5 and 20 days after treatment, respectively. The control plants did not show symptoms, and the fungus was re-isolated from the inoculated plant; thus, fulfilling Koch’s Postulates. In Korea, C. fioriniae has been recorded as a pathogen of fruit (apple, eggplant and peach), but this is the first report of the fungus causing anthracnose on Mochi tree. The pathogen has been reported on leaves of a different Ilex species in the eastern USA (Farr and Rossman 2020). Although this new disease of I. integra is limited occurrence, C. fioriniae may be able to infect other plant species in South Korea.

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First Report of Leaf Spot Caused by Corynespora cassiicola on Viburnum odoratissimum Ker-Gawl. var. awabuki (K. Koch) Zabel ex Rumpl. (sweet viburnum) in China

Plant Disease ◽

10.1094/pdis-04-21-0849-pdn ◽

2021 ◽

Author(s):

Tianning Zhang ◽

Huanhuan Liu ◽

Qingni Song ◽

Jun Liu ◽

Qingpei Yang ◽

...

Keyword(s):

Leaf Spot ◽

Leaf Spot Disease ◽

Conidial Suspension ◽

Puncture Wound ◽

First Report ◽

Leaf Spots ◽

Fungal Isolates ◽

Initial Symptoms ◽

Viburnum Odoratissimum ◽

Sweet Viburnum

Sweet viburnum [Viburnum odoratissimum Ker-Gawl. var. awabuki (K. Koch) Zabel ex Rumpl.] belonging to the family Adoxaceae, is a medical and landscape plant, native to Korea (Jeju Island), Taiwan, and Japan (Edita 1988). In June and September 2019, leaf spots were observed on approximately 65% to 80% of sweet viburnum plants in a hedgerow located in Fenghe Xincheng District (28°41'52.9"N 115°52'14.3"E) in Nanchang, China. Initial symptoms of disease appeared as dark brown spots surrounded by red halos (Figure 1 A), which expanded irregularly. Finally, the center of the lesions desiccated and became light-brown, surrounded by a deep-red halos (Figure 1 B). Ten leaf samples with typical symptoms were collected and washed with tap water for about 15 min. The tissue between the healthy and necrotic area (ca. 4 mm × 4 mm) was cut with a sterile scalpel and surface sterilized with 70% alcohol for 45 s, 2% NaClO for 2 min, washed in sterile deionized water three times, dried on sterilized filter paper, then placed in Petri dishes and incubated at 25℃ in the dark. After 3 to 5 days, the hyphal tips from the edges of growing colonies were transferred to fresh PDA dishes. Eventually, 54 fungal isolates were obtained and, of these, 39 isolates were identical in their morphological characteristics. Morphological analysis was performed according with Ellis (1971). The isolate S18, chosen as representative, formed a gray to grayish brown colony with concentric circleson PDA, and a diameter of 8.5 to 9 cm after 7 days incubation at 25℃ (Figure 1 G). Conidia were hyaline, straight or slightly curved, needle shaped, truncate at the base, and acuminate at the tip, with 2 to 6 pseudosepta, 18.90 to 38.38 µm (avg. = 27.51 µm) × 1.64 to 4.50 µm (avg. = 2.60 µm) (n = 36) (Figure 1 H). The genes of fungal isolates (i.e., ITS, tub2 and ACT) were amplified with ITS4/ITS5 for ITS (White, Bruns et al. 1990), Bt2a/Bt2b for tub2 (Glass and Donaldson 1995) and ACT783R/ACT512F for ACT (Carbone and Kohn 1999) and sequenced. The sequences were deposited in GenBank (MW165772 for ITS, MW175900 for ACT and MW168659 for tub2), which showing greater than 99.1% similarity to multiple C. cassiicola accessions, respectively. Pathogenicity tests were performed on healthy leaves in field by inoculating surface-sterilized mature leaves with puncture wound (Figure C) and non-wounded young leaves with 20 µL of a conidial suspension (105 conidia ml-1) (Figure F and G) at 26℃. After 4 to 7 days, all inoculated leaves reproduced similar symptoms as observed initially in the field (Figure 1 C, E and F). To fulfill Koch’s postulates, the fungus was isolated on PDA from the margins of leaf spots on inoculated leaves and confirmed as C. cassiicola by morphological characters and ITS gene sequencing. Previously, C. cassiicola was reported as an endophyte on Viburnum spp. and Viburnum odoratissimum (Alfieri et al. 1994). More recently, C. cassiicola has been reported as a pathogen of many plant species in China, such as kiwifruit (Cui, Gong et al. 2015), American sweetgum (Mao, Zheng et al. 2021), castor bean (Tang, Liu et al. 2020), and holly mangrove (Xie, He et al. 2020). To our knowledge, this is the first report of leaf spot disease on sweet viburnum caused by C. cassiicola in China and the precise identification of the causal agent will be useful for its management.

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First Report of Collar and Root Rot Caused by Pythium ultimum on Coriander in Italy

Plant Disease ◽

10.1094/pdis-94-9-1167b ◽

2010 ◽

Vol 94 (9) ◽

pp. 1167-1167 ◽

Cited By ~ 3

Author(s):

A. Garibaldi ◽

G. Gilardi ◽

M. L. Gullino

Keyword(s):

Root Rot ◽

Its Region ◽

Pythium Ultimum ◽

Morphological Characters ◽

Fluorescent Light ◽

Academic Press ◽

Medicinal Uses ◽

First Report ◽

Young Leaves ◽

Collar And Root Rot

Coriander, Coriandrum sativum L., is an annual herb in the family Apiaceae. This plant, native to southern Europe, northern Africa, and southeastern Asia, is used in cooking as well as for medicinal uses. The leaves are commonly referred to as cilantro. In October 2009, severe outbreaks of a previously unknown root rot were observed in a commercial field located in the Alessandria Province (northern Italy) on 20-day-old plants belonging to cv. Comune. Five percent of plants were affected, showing stunting and extensive chlorosis starting on external leaves that eventually wilted. Root systems and collars of diseased plants appeared rotted. In advanced stages, young leaves were affected and the plants eventually collapsed and tissues dried out. Tissue fragments of 1 mm2 were excised from the roots of infected plants, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and a medium selective for Oomycetes (3). Plates were incubated under constant fluorescent light at 22 ± 1°C for 4 to 5 days. One isolate, grown on V8 medium (vegetable mix, 300 g; agar, 15 g; CaCO3, 1.5g; and distilled water, 1 liter), and observed under a light microscope showed hyphae generally aseptate, ranging from 1.3 to 6.24 μm in diameter, and produced sporangia consisting of complexes of swollen hyphal branches. Oogonia were globose, smooth, and 20.3 to 33.4 (average 25.4) μm in diameter. Antheridia were monoclinous, extending from immediately below oogonium, and measured 10.8 to 17.8 × 7.6 to 12.7 (average 14.4 × 10.4) μm. Oospores were single, globose, aplerotic and thick walled, and 15.8 to 24.2 (average 17.8) μm in diameter. These morphological characters were used to identify the microorganism as a Pythium sp. (3). The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS1/ITS4 (2,4) and sequenced. BLAST analysis (1) of the 874-bp segment showed a 100% homology with the sequence of Pythium ultimum. The nucleotide sequence has been assigned the GenBank Accession No. GU478314. Pathogenicity tests were performed twice on coriander cv. Comune. Plants were grown in 2-liter pots containing a Brill Type 5 substrate (Brill Substrate GmbH & Co. KG, Niedersachsen, Germany) consisting of 15% blond peat, 85% black peat, pH 5.5 to 6, and pasteurized at 80°C for 30 min. The potting mix was infested at a rate of 5 g/liter with wheat and hemp kernels colonized with one strain of P. ultimum. Ten plants (1 plant per pot) were grown in the infested substrate and 10 plants were grown in noninfested substrate. Plants were kept in a growth chamber at 20°C. The first symptoms, consisting of reduced growth and chlorosis, developed within 7 days, while control plants remained healthy. P. ultimum was consistently isolated from the roots. To our knowledge, this is the first report of P. ultimum causing disease of coriander in Italy as well as worldwide. At this time, the economic importance of Pythium rot on coriander in Italy remains unknown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) W. Chen et al. Exp. Mycol.16:22, 1992. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Boca Raton, FL, 2002. (4) T. J. White et al. Page 38 in: PCR protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

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First Report of Powdery Mildew of Platanus × acerifolia and P. occidentalis Caused by Erysiphe platani in Greece

Plant Disease ◽

10.1094/pdis-07-14-0713-pdn ◽

2015 ◽

Vol 99 (2) ◽

pp. 286-286 ◽

Cited By ~ 3

Author(s):

E. K. Ligoxigakis ◽

E. A. Markakis ◽

I. A. Papaioannou ◽

M. A. Typas

Keyword(s):

Powdery Mildew ◽

Infected Plant ◽

Control Measures ◽

Universal Primers ◽

Morphological Description ◽

Its2 Region ◽

Conidial Suspension ◽

Platanus Acerifolia ◽

First Report ◽

Young Leaves

London planetrees (Platanus × acerifolia, syn. P. × hispanica), American sycamores (P. occidentalis), and oriental planes (P. orientalis) are widely planted as urban shade trees throughout Greece and many other countries. In June 2012, typical symptoms of a powdery mildew were detected on all sycamores (10 trees) along a central avenue of Heraklion (Crete, Greece), with the disease affecting approximately 80% of the leaves of all infected trees. In August 2013, similar symptoms were observed on 20% of the leaves of all three London planes in a small grove in the Vrysses area of Lasithi (Crete, Greece). In both cases, the disease was severe, with white superficial colonies developing amphigenously on leaves, twigs, floral peduncles, inflorescences, and fruits. The colonies were initially distinct and circular but gradually enlarged and often coalesced to cover the entire leaf blade. Young leaves appeared curled and chlorotic, occasionally leading to defoliation. For the morphological description of the pathogen, samples from seven infected P. occidentalis and three P. × acerifolia trees were microscopically characterized. In all samples, the pathogen's mycelium was branched, septate, and hyaline, with lobed appressoria; conidiophores were erect, cylindrical, unbranched, and consisted of three to four (to five) cells; and conidia were single or in short chains (two to four), ellipsoid or doliiform, with a truncated base and rounded apex. Their dimensions were 24.3 to 48.6 × 15.8 to 27.9 μm (averaging 39.2 × 21.2 μm; n = 100), and their surfaces appeared reticulate. The teleomorph was never observed. Total fungal DNA was extracted from conidia harvested from affected leaves of one infected plant of each of P. occidentalis and P. × acerifolia planes, and the ITS1-5.8S-ITS2 region was PCR-amplified with universal primers 18S-ITS1 and 28S-ITS2 (2) and sequenced (GenBank Accession Nos. KM068123 and KM068124, respectively). A BLASTn search of GenBank revealed 100% identity of both samples to Erysiphe platani strains described on P. orientalis in Greece (JQ365943) and P. occidentalis in Brazil (KF499270). Based on the morphological and molecular analyses, the pathogen was identified as E. platani (Howe) U. Braun & S. Takam. (formerly known as Microsphaera platani Howe) (1). To prove pathogenicity and fulfill Koch's postulates, 10 1-year-old seedlings of each of P. occidentalis and P. × acerifolia hosts were artificially inoculated with conidia obtained from naturally infected plants of the corresponding species, with two methods: (i) five plants of each host were dusted with conidia from diseased leaves, and (ii) the remaining five seedlings of each plane were sprayed with a conidial suspension of the fungus (107 conidia ml−1), while five additional control plants of each species were treated only with sterile distilled water. All plants were maintained in the greenhouse at 25 ± 3°C, with 90% humidity. Powdery mildew symptoms, which appeared 9 and 15 days after inoculation on all dusted and sprayed plants, respectively, were similar to those observed on naturally infected trees, whereas no symptoms were observed on control plants. Although E. platani is known to infect plane species in several parts of the world (1), including oriental planes (P. orientalis and P. orientalis var. cretica) in Greece (3), this is the first report of E. platani causing disease of P. occidentalis and P. × acerifolia in Greece, underlining the need for appropriate control measures to prevent significant losses to the local ornamental industry. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (2) I. A. Papaioannou et al. Eur. J. Plant Pathol. 136:577, 2013. (3) D. J. Vakalounakis and E. Klironomou. EPPO Bull. 25:463, 1995.

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First Report of Colletotrichum coccodes Causing Leaf and Neck Anthracnose on Onions (Allium cepa) in Michigan and the United States

Plant Disease ◽

10.1094/pdis-01-12-0022-pdn ◽

2012 ◽

Vol 96 (5) ◽

pp. 769-769 ◽

Cited By ~ 2

Author(s):

L. M. Rodriguez-Salamanca ◽

T. B. Enzenbacher ◽

M. L. Derie ◽

L. J. du Toit ◽

C. Feng ◽

...

Keyword(s):

Its Region ◽

The United States ◽

Distilled Water ◽

Conidial Suspension ◽

Water Control ◽

First Report ◽

Plastic Bags ◽

Pathogenicity Tests ◽

Colletotrichum Spp ◽

Water Plants

In July of 2010, dry, oval lesions, each with a salmon-colored center and bleached overall appearance, were observed on the leaves and neck of onions plants growing in production fields of Newaygo, Ottawa, Kent, and Ionia counties, Michigan. Acervuli and setae that are characteristic of Colletotrichum spp. were observed with a dissecting microscope, and elliptical conidia (8 to 23 × 3 to 12 μm) with attenuated ends were observed with a compound microscope. Symptomatic tissues were excised and cultured onto potato dextrose agar amended with 30 and 100 ppm of rifampicin and ampicillin, respectively. The cultures produced pale salmon-colored sporulation after growing for 5 days at 22 ± 2°C and black microsclerotia after 2 weeks. Six isolates were confirmed as C. coccodes based on sequence analysis of the internal transcribed (ITS) region of the ribosomal DNA and a 1-kb intron of the glutamine synthase gene (GS) (2). Sequences were submitted to GenBank (Accession Nos. JQ682644 and JQ682645 for ITS and GS, respectively). Pathogenicity tests were conducted on two- to three-leaved ‘Stanley’ and ‘Cortland’ onion seedlings. Prior to inoculation, seedlings were enclosed in clear plastic bags overnight to provide high relative humidity. The bags were removed, and seedlings were sprayed inoculated with a C. coccodes conidial suspension (5 × 105 conidia/ml and 25 ml/plant) in sterile double-distilled water. Control seedlings were sprayed with sterile double-distilled water. Tween (0.01%) was added to the conidial suspension and the water. Plants were enclosed in bags for 72 h postinoculation and incubated in growth chambers at 28°C day/23°C night with a 12-h photoperiod. Sunken, oval lesions were observed on the foliage of the onion seedlings inoculated with C. coccodes 4 days postinoculation. Lesions coalesced and foliage collapsed 7 days postinoculation. Control plants remained asymptomatic. When five leaf samples per replication were detached and incubated in a moist chamber for 3 days at 21 ± 2°C, abundant acervuli and setae were observed on the symptomatic tissue but not on control tissue. C. coccodes was consistently recovered from the onion seedling lesions. Six different Colletotrichum spp. have been reported to cause diseases on onions worldwide (1,4). C. circinans, which causes smudge, is an occasional onion pathogen in Michigan, while C. gloeosporioides has only been reported to be infecting onions in Georgia (3). To our knowledge, this is the first report of C. coccodes infecting and causing disease in onions plants. 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/ , August 6, 2010. (2) J. C. Guerber et al. Mycologia 95:872. 2003. (3) C. Nischwitz et al. Plant Dis. 92:974. 2008. (4) H. F. Schwartz, and K. S. Mohan. Compendium of Onion and Garlic Diseases and Pests, 2nd ed. The American Phytopathological Society, St. Paul, MN. 1995.

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