First Report of Gray Mold Caused by Botrytis cinerea on Greenhouse-Grown Zucchini in Korea

In the winter of 2011, greenhouse-grown zucchini (Cucurbita pepo) in Andong City, Korea, showed severe disease symptoms on fruits and dying leaves of zucchini plants that resembled gray mold disease with about 20% yield loss. Symptoms included extensive growth of mycelia and gray conidia on stem and fruit lesions. Lesions expanded rapidly under cool, humid conditions. As the disease progressed, leaves, stems, and fruits became necrotic and were covered by an abundant, soft, gray, sporulating mycelium. Diseased fruit tissue was excised and surface sterilized by immersion in 2% NaOCl for 1 min, placed on PDA (potato dextrose agar), and incubated at 22°C. Fungal colonies were initially white and became gray to brown after 72 h. Analysis of light micrographs showed the presence of elliptical conidia on PDA that was 7.5 to 16.0 μm long and 5 to 10.5 μm wide. In culture, a few, black, small and large irregular sclerotia were produced. Microsclerotia were round, spherical or irregular in shape, and ranged from 1.0 to 3.3 and 1.2 to 3.4 mm (width and length). Conidiophores were slender and branched with enlarged apical cells bearing smooth, ash-colored conidia. These morphological characteristics identified the fungus as Botrytis cinerea (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 (forward) and ITS4 (reverse) primer set (ITS1: 5′-TCCGTAGGTGAACCTGCGG-3′, ITS4: 5′-TCCTCCGCTTATTGATATGC-3′) and sequenced (2). BLAST analysis of the PCR product showed that the sequence had 100% identity with the nucleotide sequences for B. cinerea. Pathogenicity tests were performed by placing mycelium fragments (1 cm2) of PDA cultures on zucchini fruits. Controls were treated with PDA alone. Five replicates for the inoculated and control plants were used. All fruits were covered with plastic bags and incubated in a growth chamber to maintain 90 to 100% relative humidity at 22°C. Typical symptoms appeared 2 to 6 days after inoculation. The inoculated plants developed typical gray mold symptoms with gray sporulating lesions, while controls remained healthy with no lesions. B. cinerea reisolated from the inoculated tissues was morphologically identical to the original isolates. In a cold outside (below 0°C), wet greenhouse, plants are likely to be exposed to resident Botrytis populations and if the gray mold disease occurs, it can spread on zucchini plants very fast, in 2 days to a week inside a 100 m2 greenhouse. Therefore, gray mold disease could have a significant impact on greenhouse production of zucchini. To our knowledge, this is the first report of B. cinerea causing gray mold of greenhouse-grown zucchini in Korea. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) T. J. White et al. PCR Protocols. Academic Press, Inc., New York, 1990.

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First Report of Gray Mold of Rhizoma paridis Caused by Botrytis cinerea in China

Plant Disease ◽

10.1094/pdis-03-14-0336-pdn ◽

2014 ◽

Vol 98 (10) ◽

pp. 1434-1434 ◽

Cited By ~ 2

Author(s):

J. M. You ◽

Q. H. Wang ◽

X. M. Lin ◽

J. Guo ◽

L. Q. Ai ◽

...

Keyword(s):

Botrytis Cinerea ◽

Leading Edge ◽

Its Region ◽

Gray Mold ◽

Pathogenicity Test ◽

Heat Shock Protein 60 ◽

Chinese Medicinal Herb ◽

First Report ◽

Potted Plants ◽

Plastic Bags

Rhizoma paridis is a perennial, traditional Chinese medicinal herb. In May 2013, a disease was observed in an approximately 10 ha cultivated field in Enshi, Hubei Province, China. Approximately 80% of plants in the field were affected. Symptoms were visible on the basal leaves of affected plants. Chlorosis followed by necrosis started at the leaf tips and margins and gradually spread inward until the entire leaf was necrotic. Thick, gray mycelium and conidia were visible on both sides surface of leaves under wet, humid conditions. The leading edge of the chlorotic leaves was excised from 20 plant samples surface disinfested with 1% NaOCl solution for 1 min, rinsed in sterile water, air dried, and placed on potato dextrose agar (PDA). Plates were incubated at 22°C in the dark. Mycelia were initially hyaline and white, and became dark gray after 72 h. Mycelia were septate with dark branched conidiophores. Conidia were smooth, hyaline, ovoid, aseptate, and ranged from 8 to 14.5 × 7 to 8.5 μm. Numerous hard, small, irregular, and black sclerotia that were 1 to 3 × 2 to 5 mm were visible on PDA plates after 12 days. The fungus was identified as Botrytis cinerea on the basis of these characters (1). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 and ITS4 primer and sequenced (GenBank Accession No. KF265499). BLAST analysis of the PCR product showed 99% identity to Botryotinia fuckeliana (perfect stage of B. cinerea) (EF207415.1, EF207414.1). The pathogen was further identified to the species level as B. cinerea using gene sequences from glyceraldehyde-3-phosphate dehydrogenase (G3PDH), heat-shock protein 60 (HSP60), and DNA-dependent RNA polymerase subunit II (RPB2) (2) (KJ638600, KJ638602, and KJ638601). Pathogenicity was tested by spraying the foliage of 40 two-year-old plants with a suspension of 106 conidia per ml of sterile distilled water. Each plant received 30 ml of the inoculum. Ten healthy potted plants were inoculated with sterilized water as control. All plants were covered with plastic bags for 5 days after inoculation to maintain high relative humidity and were placed in a growth chamber at 22°C. The first foliar lesions developed on leaves 7 days after inoculation and were similar to those observed in the field. No symptoms developed on the control plants. B. cinerea was consistently re-isolated from all artificially inoculated plants. The pathogenicity test was completed twice. To our knowledge, this is the first report of gray mold of R. paridis caused by B. cinerea in China. The root of R. paridis is the most commonly used Chinese herbal medicine to treat viper bites. In recent years, cultivation of this herb has increased in China because of its high value. Consequently, the economic importance of this disease is likely to increase with the greater prevalence of this host species. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (2) M. Staats et al. Mol. Biol. Evol. 22:333, 2005.

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First Report of Black Rot of Carrots Caused by Alternaria radicina in Michigan

Plant Disease ◽

10.1094/pd-90-0684b ◽

2006 ◽

Vol 90 (5) ◽

pp. 684-684

Author(s):

C. Saude ◽

M. K. Hausbeck

Keyword(s):

United States ◽

New York ◽

Sequence Similarity ◽

Morphological Characteristics ◽

Its Region ◽

The United States ◽

Distilled Water ◽

First Report ◽

Plastic Bags ◽

Alternaria Sp

In April 2005, an Alternaria sp. was isolated from carrot (Daucus carota) roots harvested in the fall of 2004 and held at 1 to 3°C in a storage facility in Newaygo County, MI. The pathogen was readily isolated on water agar from root tissue exhibiting grayish black, sunken lesions. Morphological characteristics were noted 5 to 7 days after single-conidium cultures were established on potato dextrose agar (3). Sixteen Alternaria sp. isolates were recovered. Cultures were dark olive brown, and conidia were pigmented, ellipsoidal, and produced singly or in chains of two. Conidia were 35 to 45 μm long and 15 to18 μm in diameter, usually with three to eight transverse and one to four longitudinal septa. Pathogenicity of isolates was tested on carrot roots in the laboratory and carrot seedlings (cv. Goliath) in the greenhouse. In the laboratory, four surface-sterilized, whole carrot roots were sprayed until runoff with 2 × 106 conidia/ml of each isolate and incubated at 23 to 25°C in a moist chamber for 10 days. Controls were sprayed with sterile distilled water. Ten to fifteen days after inoculation, inoculated carrots exhibited grayish black, sunken lesions, and an Alternaria sp. was reisolated from the margin of the lesions. Controls remained healthy. In the greenhouse, seven pots containing one 2-week-old carrot seedling were watered to saturation and plants were sprayed until runoff with 2 × 106 conidia/ml for each isolate. Control plants were sprayed with sterile distilled water. After inoculation, plants were enclosed in clear plastic bags, placed under 63% woven shade cloth and watered regularly. Black lesions were observed on the foliage 7 days after inoculation, and wilt and death of plants were observed 15 to 30 days after inoculation. Alternaria sp. was reisolated from the foliage of symptomatic plants. Control plants remained healthy. DNA was extracted from all isolates, and the nuclear ribosomal internal transcribed spacer (ITS) region amplified with primers ITS4 and ITS5 and sequenced. A portion of the ITS sequence has been deposited in the NCBI database (GenBank Accession No. DQ394073). A BLAST search of the NCBI database with the ITS sequences revealed A. radicina, Accession No AY154704, as the closest match with 100% sequence similarity. In September 2005, an Alternaria sp. was isolated from black lesions on carrot roots, crowns, and foliage that were collected from fields in Newaygo and Oceana counties, MI. The recovered isolates were morphologically similar to A. radicina isolates obtained from stored carrots in April 2005. First isolated and identified on stored carrots in New York (3), A. radicina is also present in other carrot-producing areas of the United States (1) and was isolated not only from stored carrots but also from carrots in the field (2) and carrot seeds (4). To our knowledge, this is the first report of A. radicina on stored and field carrots in Michigan, which signifies a serious risk to a carrot industry that ranks among the top five in the United States. References: (1) D. F. Farr et al. Fungi on Plants and Plant Produce in the United States.The American Phytopathological Society, St. Paul, MN, 1989. (2) R. G. Grogan and W. C. Snyder. Phytopathology 42:215, 1952. (3) F. C. Meier and E. D. Eddy. Phytopathology 12:157, 1922. (4) B. M. Pryor and R. L. Gilbertson. Plant Dis. 85:18, 2001.

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First Report of Leaf Spot Caused by Botrytis cinerea on Cardamine hupingshanensis in China

Plant Disease ◽

10.1094/pdis-04-21-0698-pdn ◽

2021 ◽

Author(s):

Jun Guo ◽

Jin Chen ◽

Zhao Hu ◽

Jie Zhong ◽

Jun Zi Zhu

Keyword(s):

Botrytis Cinerea ◽

Morphological Characteristics ◽

Gray Mold ◽

Hunan Province ◽

Conidial Suspension ◽

Heat Shock Protein 60 ◽

Basal Cells ◽

Single Spore ◽

Internal Transcribed Spacer Region ◽

First Report

Cardamine hupingshanensis is a selenium (Se) and cadmium (Cd) hyperaccumulator plant distributed in wetlands along the Wuling Mountains of China (Zhou et al. 2018). In March of 2020, a disease with symptoms similar to gray mold was observed on leaves of C. hupingshanensis in a nursery located in Changsha, Hunan Province, China. Almost 40% of the C. hupingshanensis (200 plants) were infected. Initially, small spots were scattered across the leaf surface or margin. As disease progressed, small spots enlarged to dark brown lesions, with green-gray, conidia containing mold layer under humid conditions. Small leaf pieces were cut from the lesion margins and were sterilized with 70% ethanol for 10 s, 2% NaOCl for 2 min, rinsed with sterilized distilled water for three times, and then placed on potato dextrose agar (PDA) medium at 22°C in the dark. Seven similar colonies were consistently isolated from seven samples and further purified by single-spore isolation. Strains cultured on PDA were initially white, forming gray-white aerial mycelia, then turned gray and produced sclerotia after incubation for 2 weeks, which were brown to blackish, irregular, 0.8 to 3.0 × 1.2 to 3.5 mm (n=50). Conidia were unicellular, globose or oval, colourless, 7.5 to 12.0 × 5.5 to 8.3 μm (n=50). Conidiophores arose singly or in group, straight or flexuous, septate, brownish to light brown, with enlarged basal cells, 12.5 to 22.1 × 120.7 to 310.3 μm. Based on their morphological characteristics in culture, the isolates were putatively identified as Botrytis cinerea (Ellis 1971). Genomic DNA of four representative isolates, HNSMJ-1 to HNSMJ-4, were extracted by CTAB method. The internal transcribed spacer region (ITS), glyceraldehyde-3-phosphate dehydrogenase gene (G3PDH), heat-shock protein 60 gene (HSP60), ATP-dependent RNA helicaseDBP7 gene (MS547) and DNA-dependent RNA polymerase subunit II gene (RPB2) were amplified and sequenced using the primers described previously (Aktaruzzaman et al. 2018) (MW820311, MW831620, MW831628, MW831623 and MW831629 for HNSMJ-1; MW314722, MW316616, MW316617, MW316618 and MW316619 for HNSMJ-2; MW820519, MW831621, MW831627, MW831624 and MW831631 for HNSMJ-3; MW820601, MW831622, MW831626, MW831625 and MW831630 for HNSMJ-4). BLAST searches showed 99.43 to 99.90% identity to the corresponding sequences of B. cinerea strains, such as HJ-5 (MF426032.1, MN448500.1, MK791187.1, MH727700.1 and KX867998.1). A combined phylogenetic tree using the ITS, G3PDH, HSP60 and RPB2 sequences was constructed by neighbor-joining method in MEGA 6. It revealed that HNSMJ-1 to HNSMJ-4 clustered in the B. cinerea clade. Pathogenicity tests were performed on healthy pot-grown C. hupingshanensis plants. Leaves were surface-sterilized and sprayed with conidial suspension (106 conidia/ mL), with sterile water served as controls. All plants were kept in growth chamber with 85% humidity at 25℃ following a 16 h day-8 h night cycle. The experiment was repeated twice, with each three replications. After 4 to 7 days, symptoms similar to those observed in the field developed on the inoculated leaves, whereas controls remained healthy. The pathogen was reisolated from symptomatic tissues and identified using molecular methods, confirming Koch’s postulates. B. cinerea has already been reported from China on C. lyrate (Zhang 2006), a different species of C. hupingshanensis. To the best of our knowledge, this is the first report of B. cinerea causing gray mold on C. hupingshanensis in China and worldwide. Based on the widespread damage in the nursery, appropriate control strategies should be adopted. This study provides a basis for studying the epidemic and management of the disease.

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

Plant Disease ◽

10.1094/pdis-05-11-0362 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1188-1188 ◽

Cited By ~ 6

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.

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First Report of Alternaria heveae Causing Black Leaf Spot of Rubber Tree in China

Plant Disease ◽

10.1094/pdis-01-14-0065-pdn ◽

2014 ◽

Vol 98 (7) ◽

pp. 1011-1011 ◽

Cited By ~ 1

Author(s):

Z. Y. Cai ◽

Y. X. Liu ◽

G. X. Huang ◽

M. Zhou ◽

G. Z. Jiang ◽

...

Keyword(s):

Rubber Tree ◽

Morphological Characteristics ◽

Black Spot ◽

Its Region ◽

Post Inoculation ◽

First Report ◽

Leaf Spots ◽

Plastic Bags ◽

Manual Pressure ◽

Tree Leaf

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop of tropical areas for natural rubber production. In October 2013, foliar spots (0.1 to 0.4 mm in diameter), black surrounded by a yellow halo, and with lesions slightly sunken were observed on the rubber tree leaf in a growing area in Heikou County of Yunnan Province. Lesion tissues removed from the border between symptomatic and healthy tissue were surface sterilized in 75% ethanol and air-dried, plated on PDA plates, and incubated at 28°C with alternating day/night cycles of light. The pathogen was observed growing out of many of the leaf pieces, and produced abundant conidia. Colonies 6.1 cm in diameter developed on potato carrot agar (PCA) after 7 days, with well-defined concentric rings of growth. Colonies on PCA were composed of fine, dark, radiating, surface and subsurface hyphae. Conidia produced in PCA culture were mostly solitary or in short chains of 2 to 5 spores, long ovoid to clavate, and light brown, 40 to 81.25 × 8 to 20 μm (200 colonies were measured), with 3 to 6 transverse septa and 0 to 2 longitudinal or oblique septa. Morphological characteristics were similar to those described for Alternaria heveae (3,4). A disease of rubber tree caused by Alternaria sp. had been reported in Mexico in 1947 (2). DNA of Ah01HK13 isolate was extracted for PCR and sequencing of the ITS region with ITS1 and ITS4 primers was completed. From the BLAST analysis, the sequence of Ah01HK13 (GenBank Accession No. KF953884), had 97% similarity to A. dauci, 96% identical to A. macrospora (AY154701.1 and DQ156342.1, respectively), indicating the pathogen belonged to Alternaria genus. According to morphological characteristics, this pathogen was identified as A. heveae. Pathogenicity of representative isolate, Ah01HK13 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage and inoculated by spraying spore suspension (concentration = 104 conidia/ml) to the copper-colored leaves until drops were equally distributed on it using manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags. The plastic bags were removed after 2 days post-inoculation (dpi) and monitored daily for symptom development (1). The experiment was repeated three times. The typical 0.1 to 0.4 mm black leaf spots were observed 7 dpi. No symptoms were observed on control plants. A fungus with the same colony and conidial morphology as A. heveae were re-isolated from leaf lesions on inoculated rubber plants, but not from asymptomatic leaves of control plants, fulfilling Koch's postulates. Based on these results, the disease was identified as black spot of rubber tree caused by A. heveae. To our knowledge, this is the first report of A. heveae on rubber tree in China. References: (1) Z. Y. Cai et al. Microbiol Res. 168:340, 2013. (2) W. J. Martin. Plant Dis. Rep. 31:155, 1947. (3) E. G. Simmons. Mycotaxon 50:262, 1994. (4) T. Y. Zhang. Page 111 in: Flora Fungorum Sinicorum: Alternaria, Science Press, Beijing, 2003.

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First Report of Gray Mold on Amorphophallus muelleri Caused by Botrytis cinerea in China

Plant Disease ◽

10.1094/pdis-08-13-0855-pdn ◽

2014 ◽

Vol 98 (5) ◽

pp. 692-692 ◽

Cited By ~ 2

Author(s):

L. Yu ◽

J. R. Zhao ◽

S. G. Xu ◽

Y. Su ◽

D. Gao ◽

...

Keyword(s):

Botrytis Cinerea ◽

Its Region ◽

Gray Mold ◽

Gelling Agent ◽

Commonwealth Mycological Institute ◽

Distilled Water ◽

First Report ◽

Calla Lily ◽

Specialty Crop ◽

Important Cash Crop

Amorphophallus muelleri is a perennial tuberous plant in the family Araceae. The name konjac is commonly used for the species of genus Amorphophallus that produce a polysaccharide, glucomannan. The latter, called konjac glucomannan, is extracted from the tubers of these species. Glucomannan is an excellent gelling agent used in food, pharmaceutical and chemical industry, a specialty crop grown as a source of glucomannan for industrial use. It is an important cash crop and thus contributes to poverty alleviation in southwest China. Its planting area is about 150 million mu (10 million ha). In July 2012, symptoms of an unknown blight were observed on 5 to 10% of A. muelleri flowers and seeds being grown for commercial seed production. Greenhouses temperatures ranged from 20 to 34°C (avg. 26°C). A light grey mycelium was observed on symptomatic tissues, especially flowers. Severely infected flowers and stems eventually rotted, then dried out. Diseased tissue was excised from affected flowers and surfaces and disinfected with 1% sodium hypochlorite, followed by 70% alcohol. The tissue was then rinsed in sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 26°C. Mycelial growth on PDA was initially whitish and turned gray with age. Dark appearing conidiophores bore botryose heads of hyaline, ellipsoid, unicellular conidia, grey in mass, measuring 7.2 (6.2 to 9.5) × 5.3 (4.5 to 6.0) μm. Black, irregular sclerotia formed at random in the culture. These morphological features were typical of those described for Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced (1). BLAST analysis of a 557-bp segment had a 99% similarity with the sequence of Botryotinia fuckeliana (anamorph = B. cinerea). The representative nucleotide sequence has been assigned the GenBank Accession No. KC999986. On the basis of morphological and molecular results, the fungus isolated from diseased konjac flowers and flower tissue was confirmed to be B. cinerea. Pathogenicity tests: Inoculum was prepared from 7-day-old cultures on PDA. Six flowering A. muelleri in 1-liter pots were spray inoculated with a 1.0 × 106 conidia/ml suspension from 7-day-old PDA cultures. As a control, six healthy plants were sprayed with sterile distilled water. Each plant was covered with a transparent polyethylene bag for 3 days and maintained in a greenhouse at temperatures between 20 and 26°C. After 8 days, small, round to irregular brown spots developed on both flowers and stems, which finally blighted. Water-treated plants remained symptomless. Koch's postulates were fulfilled when the pathogen was re-isolated from the diseased organs. Blight on common calla lily (calla lily and Amorphophallus are in the same family, different genera) flower attributed to B. cinerea was previously reported in Argentina (3). To our knowledge, this is the first report of the presence of B. cinerea on A. muelleri in China. References: (1) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) M. C. Rivera and S. E. Lopez. Plant Dis. 90:970, 2006.

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First Report of Pestalotiopsis microspora Causing Leaf Spot of Hidcote (Hypericum patulum) in Japan

Plant Disease ◽

10.1094/pdis-94-8-1064b ◽

2010 ◽

Vol 94 (8) ◽

pp. 1064-1064 ◽

Cited By ~ 3

Author(s):

M. Zhang ◽

H. Y. Wu ◽

T. Tsukiboshi ◽

I. Okabe

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Basal Cells ◽

Single Spore ◽

Management Options ◽

First Report ◽

Leaf Spots ◽

Plastic Bags ◽

Pestalotiopsis Microspora

Hidcote, Hypericum patulum Thunb. ex Murray, is a deciduous shrub that is cultivated as an ornamental in landscape gardens and courtyards in Japan. In early August 2008, severe leaf spotting was observed on plants growing in a courtyard in Nasushiobara, Tochigi, Japan. More than 30% of the leaves on five shrubs exhibited leaf spot symptoms. Small, round, pale brown lesions were initially observed. Later, they expanded to 5 to 12 mm in diameter, round to irregular-shaped with pale brown centers and dark brown margins. Under continuously wet or humid conditions, black acervuli developed on the leaf lesions. Conidia were straight or slightly curved, fusiform to clavate, and five-celled with constrictions at the septa. Conidia ranged from 17 to 21 × 5 to 8 μm with hyaline apical and basal cells. Fifteen percent of apical cells had two and the rest had three appendages (setulae) ranging from 10 to 21 μm long. The basal hyaline cell tapered into a 2 to 4 μm pedicel. The three median cells ranged from light or dark brown to olive green. These morphological characteristics matched those of Pestalotiopsis microspora (Speg.) G.C. Zhao & N. Li (1,2). The identity of the fungus was confirmed by DNA sequencing of the internal transcribed spacer (ITS) region (GenBank Accession No. GU908473) from single-spore isolates, which revealed 100% homology with those of other P. microspora isolates (e.g., GenBank Accession Nos. FJ459950 and DQ456865). Koch's postulates were confirmed using leaves of three detached branches of a field-grown asymptomatic plant of H. patulum. Thirty leaves of each branch were inoculated by placing mycelial plugs obtained from the periphery of 7-day-old single-spore cultures on the leaf surface. Potato dextrose agar plugs without mycelium served as controls. Leaves on branches were covered with plastic bags for 24 h to maintain high relative humidity in a greenhouse (approximately 24 to 28°C). After 5 days, all inoculated leaves showed symptoms identical to those described above, whereas control leaves remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was P. microspora. To our knowledge, this is the first report of leaf spots on H. patulum caused by P. microspora in Japan. Management options may have to be developed and implemented to protect Hidcote plants in areas where leaf spot cannot be tolerated. References: (1) P. A. Saccardo. Sylloge Fungorum III:789, 1884. (2) G. C. Zhao and N. Li. J. Northeast For. Univ. 23(4):21, 1995.

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First Report of Phytophthora cambivora Causing Leaf and Stem Blight and Root Rot on Taiwan Cherry (Prunus campanulata) in Taiwan

Plant Disease ◽

10.1094/pdis-01-12-0025-pdn ◽

2012 ◽

Vol 96 (7) ◽

pp. 1065-1065

Author(s):

J.-H. Huang ◽

P.-J. Ann ◽

Y.-H. Chiu ◽

J.-N. Tsai

Keyword(s):

Severe Disease ◽

Morphological Characteristics ◽

Its Region ◽

Internal Transcribed Spacers ◽

Nuclear Ribosomal Dna ◽

Linear Growth Rate ◽

Fluorescent Light ◽

Width Ratio ◽

First Report ◽

Zoospore Suspension

Taiwan cherry or Formosan cherry (Prunus campanulata Maxim.) is a beautiful ornamental tree that is native to Taiwan. In spring 2005, a severe disease was observed on 1- to 3-year-old seedlings of Taiwan cherry in a garden in Tungshih, Taichung, Taiwan. Infected plants showed symptoms of greenish water-soaked spots on leaves that became dark brown, 2 to 3 cm in diameter. Infected leaves withered and fell to the ground in 3 to 5 days and young shoots showed symptoms of withering and drooping. Infected roots showed symptoms of necrosis. Severely infected plants eventually died. A Phytophthora sp. was isolated consistently from diseased samples of Taiwan cherry and associated soil. Six isolates of Phytophthora, of the A1 mating type (1), were isolated from single zoospores. Two of these isolates, Tari 25141 (deposited as BCRC34932 in Bioresource Collection and Research Center, Shinchu, Taiwan) and Tari 25144 (BCRC34933), were used for pathogenicity tests on 1-year-old seedlings of Taiwan cherry to fulfill Koch's postulates. Inoculation was done by placing a cotton swab containing zoospore suspension on leaves or stem, or by soaking seedlings in the zoospore suspension. Inoculated seedlings were kept in a greenhouse at 20 to 25°C for 30 days and examined for appearance of symptoms. Results showed that both isolates were pathogenic on seedlings of Taiwan cherry, causing symptoms similar to those observed on naturally infected seedlings. The temperature range for growth of the six isolates of Phytophthora was 8 to 32°C with optimum temperature at 24°C. The linear growth rate was 72 mm per day on V8A culture (5% V8 vegetable juice, 0.02% CaCO3, and 2% Bacto agar) at 24°C. The colonies on potato dextrose agar produced sparse aerial mycelia with conspicuous radiate patterns. Sporangia were sparse on V8A agar blocks, but abundant when the agar blocks were placed in water under continuous white fluorescent light (average 2,000 lux) for 2 days. Sporangiophores branched sympodially. Sporangia were pear shaped, nonpapillate and nondeciduous, 50 to 75 (62) × 30 to 48 (40) μm, with a length/width ratio of 1.2 to 2.2 (1.6). New internal nested proliferate sporangia were formed inside the empty sac of old matured sporangia after releasing zoospores. No chlamydospores were formed on V8A. Hyphal swellings with distinctive irregular catenulation were produced on V8A and in water. The pathogen was stimulated to form its own oospores by the A2 tester using the method described by Ko (1). Oogonia were 28 to 50 (40) μm in diameter with smooth or irregularly protuberant walls. Oospores were mostly aplerotic and 18 to 42 (31) μm in diameter. Antheridia were amphigynous, mostly two-celled, and 10 to 42 (29) × 12 to 24 (19) μm. The sequence of the internal transcribed spacers (ITS) region of nuclear ribosomal DNA of isolate Tari 25141 (GenBank Accession No. GU111589) was 831 bp and had 99% sequence identity with a number of Phytophthora cambivora isolates such as GenBank Accession Nos. HM004220 (2), AY787030, and EF486692. Based on the morphological characteristics of sporangia and sexual structures and the molecular analysis of ITS sequences, the pathogen from Taiwan cherry was identified as P. cambivora (Petri) Buis. To our knowledge, this is the first report of P. cambivora on native Taiwan cherry in Taiwan and, so far, no other natural hosts have been reported. References: (1) W. H. Ko. J. Gen. Microbiol. 116:459, 1980. (2) P. W. Reeser et al. Mycologia 103:225, 2011.

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First Report of Bipolaris peregianensis Causing Leaf Spot of Cynodon dactylon in China

Plant Disease ◽

10.1094/pdis-12-11-1066-pdn ◽

2012 ◽

Vol 96 (6) ◽

pp. 917-917 ◽

Cited By ~ 2

Author(s):

Z. Y. Wang ◽

S. N. Xie ◽

Y. Wang ◽

H. Y. Wu ◽

M. Zhang

Keyword(s):

Leaf Spot ◽

Cynodon Dactylon ◽

Control Strategies ◽

Tap Water ◽

Morphological Characteristics ◽

Its Region ◽

Basal Cells ◽

First Report ◽

Leaf Spots ◽

Plastic Bags

Cynodon dactylon is widely cultivated as a sod crop in warm climates worldwide. In early September 2009, heavy leaf spot infection was observed on C. dactylon from Zhengzhou, Henan, China. Early symptoms appeared as small, elliptical, pale brown lesions on the leaves. Lesions later expanded to 5 to 10 mm long and 1 to 2 mm wide, becoming brown to dark brown. A fungus was consistently isolated from leaf spots on potato dextrose agar (PDA), but with poor sporulation. Morphological characteristics were observed from single-conidium cultures on tap water agar + wheat straw (TWA+W) after 5 to 7 days. Conidiophores were light to medium brown, cylindrical, solitary or clustered, unbranched, usually with basal cells enlarged, and 94.5 to 147.0 × 4.0 to 9.0 μm. Conidia were fusoid, strongly curved, end cells broadly hemiellipsoidal, brown, 58.5 to 84.5 × 13.5 to 18.5 μm, with 6 to 10 septa. These morphological characteristics are similar to those of Bipolaris peregianensis (2). The identity of our fungus was confirmed to be B. peregianensis by DNA sequencing of the internal transcribed spacer (ITS) region (GenBank Accession No. JQ316121), which was 99% homologous to those of other B. peregianensis isolates (= Cochliobolus peregianensis; Accession Nos AF071328 and AF158111) (1). Koch's postulates were performed with the leaves of three pots of C. dactylon. Leaves were sprayed with 1 × 105 conidia/ml of B. peregianensis; an equal number of leaves in the pots of the same plant sprayed with sterile distilled water served as the control. All test plants were covered with plastic bags for 24 h to maintain high relative humidity at 23 to 25°C. After 7 days, more than 50% of inoculated leaves showed symptoms identical to those observed in natural condition, whereas controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was B. peregianensis. To our knowledge, this is the first report of leaf spots caused by B. peregianensis on C. dactylon in China. The disease cycle and the control strategies in the regions are being further studied. References: (1) M. L. Berbee et al. Mycologia 91:964, 1999. (2) A. Sivanesan. Mycol. Pap. 158:1, 1987.

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First Report of Neofusicoccum parvum Causing Panicle Blight and Leaf Spot on Vitis heyneana in China

Plant Disease ◽

10.1094/pdis-05-14-0515-pdn ◽

2015 ◽

Vol 99 (3) ◽

pp. 417-417 ◽

Cited By ~ 4

Author(s):

D. D. Wu ◽

G. Fu ◽

Y. F. Ye ◽

F. Y. Hu ◽

H. F. Mou ◽

...

Keyword(s):

Leaf Spot ◽

Severe Disease ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Its Region ◽

Average Diameter ◽

Wine Production ◽

Neofusicoccum Parvum ◽

First Report ◽

Panicle Blight

The climbing vine, Vitis heyneana Roem. & Schult, is a member of the grape family endemic to Asia. Its fruits are used in wine production, and its roots, stems, and leaves can be used in medicinal materials. This plant is grown in Southwest China, as well as in India, Bhutan, and Nepal. Mulao Autonomous County in Guangxi Province is the only artificial cultivation area in China. During the summer of 2013, a panicle blight and leaf spot were detected on V. heyneana on four farms in Mulao Autonomous County. The symptoms were observed from the onset of florescence through fruit harvest. Brown lesions initially appeared at the base of a panicle and then extended to the whole panicle, finally causing the panicle to die and fruit to drop. When the disease developed on leaves, the symptom initially appeared as small dark brown circular spots, later enlarging into irregular spots (average diameter 6 mm) with a light brown center and dark brown rim. With severe disease, some individual leaves were affected by numerous spots, leading to premature senescence. Small sections of diseased tissue excised from 10 panicle and 10 leaf samples were plated on potato dextrose agar (PDA) and incubated at 28°C. Fungal colonies developed, initially with abundant white aerial mycelium, which turned olivaceous gray after 5 days and formed black pycnidia after 25 days. The conidia were hyaline, ellipsoidal to fusiform, externally smooth, thin-walled, and nonseptate. Thirty conidia were measured; the dimensions were 12.0 to 17.5 × 4.0 to 6.0 μm. Morphological characteristics of the isolates were similar to the descriptions of Neofusicoccum parvum (3). The isolate MPT-1 was selected as a representative for molecular identification. Genomic DNA was extracted and used for PCR to amplify the internal transcribed spacer (ITS) region and partial translation elongation factor 1-alpha (EF1-α) gene, using primers ITS1/ITS4 and EF1-728F/EF1-986R, respectively. The obtained ITS sequence (GenBank Accession No. KJ599627) and EF1-α sequence (KM921768) showed >99% homology with several GenBank sequences of N. parvum. Morphological and molecular results confirmed the isolate as N. parvum. For pathogenicity tests, detached, young healthy panicles and leaves of V. heyneana were surface-sterilized, wounded by sterile needle, and inoculated with mycelial plugs (3 mm in diameter) of four N. parvum isolates. Ten panicles and 10 leaves were used for every isolate. Control panicles and leaves were treated with sterile PDA plugs. All the samples were placed in a humid chamber (RH 90%, 28°C, 12 h of light) for 3 days. Symptoms similar to those observed in the field developed on all panicles and leaves inoculated with N. parvum isolates. N. parvum was reisolated from all inoculated, symptomatic tissues. The controls remained symptomless. N. parvum has been reported to cause trunk canker on V. vinifera (2), dieback on Cupressus funebris (3), and a leaf spot on Myristica fragrans (1). To our knowledge, this is the first report of N. parvum causing panicle blight and leaf spot on V. heyneana in China. Panicle blight caused a large number of fruits to drop and reduced the yield seriously. Some effective measures should be taken to control this disease. References: (1) V. Jayakumar et al. New Dis. Rep. 23:19, 2011. (2) J. Kaliternam et al. Plant Dis. 97:1656, 2013. (3) S. B. Li et al. Plant Dis. 94:641, 2010.

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