First Report of Fusarium commune Causing Stalk Rot on Maize in Liaoning Province, China

In a field survey from 2017 to 2019, Fusarium stalk rot symptoms including discolored, disintegrated stalk pith tissues and lodged plants were observed in maize hybrid lines Fuyu1611, Jidan66, and Danyu8439 grown in fields in Anshan (40o49′39′′N, 122 o34′6′′E), Liaoning province. Its incidence ranged from 15% to 20% and caused a yield loss of up to 30%. Infected pieces of stem tissues were dissected and then sterilized with 1% NaOCl for 1 min, 70% ethanol for 1 min, rinsed 3 times with sterilized ddH2O, and dried with filter paper in hood. Three pieces were placed onto Potato dextrose agar (PDA) and incubated at 25 °C for 5 days. The colonies were single-spore subcultured on PDA at 25 °C for 2 weeks (Leslie and Summerell 2006). Morphological features were observed on PDA and carnation leaf agar (CLA). The average mycelial growth rate was 4.5 to 10.3 mm/day at 25 °C on PDA. The colonies produced aerial mycelia, varying from dense white to grayish-rose, and secreted red pigments in the agar (Fig. 1A; 1B). Macroconidia produced on CLA were long and relatively slender, commonly 4- to 7-septate, averaging 85.6 × 5.2 μm, with thick walls and pronounced dorsiventral curvature with a distinctly foot-shaped and elongated basal cell and an apical cell that was whip-like (Fig. 1C). Microconidia were rarely observed on PDA or CLA. Morphological characteristics of the isolates were similar to the features of Fusarium longipes as previously described (Leslie and Summerell 2006). The portions of three phylogenic loci (EF1-α, RPB1, RPB2) were PCR amplified using the primer pairs EF1/EF2 (O'Donnell et al, 1998), lonR1F/lonR1R (5-TTTTCCTCACCAAGGAGCAGATCATG-3 and 5-CCAATGGACTGGGCAGCCAAAACGCC-3) and lonR2F/lonR2R (5-TATACATTTGCCTCCACTCTTTCCCAT-3 and 5-CGGAGCTTGCGTCCGGTGTGGCCGTTG-3) and sequenced. The consensus sequences were submitted to GenBank (MT513215 and MT997083 for TEF, MT513213 and MT997088 for RPB1; MT513214 and MW020572 for RPB2). BLASTn searches indicated that the nucleotide sequences of the three loci of the two isolates shared 94.52% to 99.69% identity with sequences of F. longipes strains deposited in the GenBank, Fusarium-ID and Fusarium MLST databases (Supplementary Table 1, 3, 4). A phylogram inferred via maximum likelihood analysis of the combined EF-1α, RPB1, RPB2 partial sequence data of Fusarium species (Supplementary Table 2) was inferred using the CIPRIES website (https://www.phylo.org). Isolates LNAS-05-A and LNAS-09-A clustered with F. longipes, with 98% bootstrap support (Fig. 2). Pathogenicity tests were conducted on three-leaf-stage seedlings and flowering-stage c.v. Zhengdan958 and B104 plants according to previously described methods (Ye et al., 2013; Zhang et al. 2016) with minor modifications. Three days after the roots of the seedlings were inoculated with 1 × 106 macroconidia solution, the leaves and stems exhibited typical wilt symptoms (Fig. 1D). Twenty flowering-stage maize plants were drilled individually at the second or third node above the soil using an electric drill (Bosch TSR1080-2-Li) to create a hole (8 mm in diameter). An approximately 0.5 mL mycelia plug (125 mL homogenized hyphal mats + 75 mL sterilized ddH2O) was injected into the hole and covered with Vaseline. Sterilized PDA plugs were used as a control. The stalk tissue of the split internodes turned dark brown and the brown area expanded above and below the injection site by 14 dpi. All of the inoculated plants developed characteristic stalk rot symptoms, whereas no symptoms were observed in the controls (Fig. 1E). The pathogen was re-isolated, and its identity was confirmed by sequencing the above mentioned loci. F. longipes was generally regarded as a tropical Fusarium species (Leslie and Summerell 2006). This is the first report that F. cf. longipes can cause stalk rot of maize under filed condition in a temperate, typical corn belt region of China.

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First Report of Fusarium oxysporum Causing Stalk Rot and Root Rot of Portulaca molokiniensis in China

Plant Disease ◽

10.1094/pdis-12-17-1892-pdn ◽

2018 ◽

Vol 102 (12) ◽

pp. 2650-2650

Author(s):

S. Ma ◽

Z. Cao ◽

Q. Qu ◽

N. Liu ◽

M. Xu ◽

...

Keyword(s):

Fusarium Oxysporum ◽

Root Rot ◽

First Report ◽

Stalk Rot

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First report of Lasiodiplodia brasiliense causing maize stalk rot

Australasian Plant Disease Notes ◽

10.1007/s13314-018-0320-7 ◽

2018 ◽

Vol 13 (1) ◽

Cited By ~ 2

Author(s):

F. M. Aguiar ◽

R. V. Costa ◽

D. D. Silva ◽

U. G. P. Lana ◽

E. A. Gomes ◽

...

Keyword(s):

First Report ◽

Stalk Rot

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First Report of Pythium aphanidermatum Causing Stalk Rot on Abelmoschus manihot (L. ) Medic in China

Plant Disease ◽

10.1094/pdis-06-21-1133-pdn ◽

2021 ◽

Author(s):

Qing Qu ◽

Liu Shiwei ◽

Ning Liu ◽

Yunxia Liu ◽

Jia Hui ◽

...

Keyword(s):

Management Practices ◽

Vascular System ◽

Morphological Characteristics ◽

Pythium Aphanidermatum ◽

Negative Control ◽

Perennial Herb ◽

Universal Primers ◽

First Report ◽

Stalk Rot ◽

Aerial Hyphae

Abelmoschus manihot (Linn. ) Medicus (A. manihot) is an annual to perennial herb of the Malvaceae okra, mainly distributed in Guangdong, Guangxi, Fujian, Hunan, Hubei provinces. It can not only be used as an ornamental flower, but also has important economic and medicinal value. Last year, 10% A. manihot in 1,000 acres were observed with stalk rot in the Zhongshang Agricultural Industrial Park, 50 meters east of Provincial Highway 235 in Gaoyang County of Hebei province. Internal discoloration of the stem began brown to black discoloration of the vascular system and became hollow, with the mycelium growing on the surface. Stems from symptomatic plants (approximately 5 mm2) were dissected, washed free of soil, then soaked in 75% ethanol for 16 s to surface-sterilize, and 40 s in HgCl2, then rinsed three times in sterile water. After being dried with blotting paper, five pieces were placed on potato dextrose agar (PDA). After cultured 2 or 3 days, five isolates were purified and re-cultured on PDA in the dark at 25°C. The color of the colony was white. The hyphae were radial in PDA, and the aerial hyphae were flocculent, well-developed with luxuriant branches. The colonies were white and floccus, and the aerial hyphae were well developed, branched and without septum on corn meal agar (CMA). The sporangia were large or petal shaped, composed of irregular hyphae, terminal or intermediate , with the size of (31.6-88.4) μm ×(12.7- 14.6) μm. Vesicles were spherical, terminal or intermediate, ranging from 14.6 to 18.5μm. Oogonia were globose, terminal and smooth which stipe was straight. Antheridia were clavate or baggy and mostly intercalary, sometimes terminal. Oospores were aplerotic, 21.5 to 30.0 μm in diameter, 1.6 to 3.1 μm in wall thickness. The isolates morphological characteristics were consistent with P. aphanidermatum (van der Plaats-Niterink 1981, Wu et al. 2021 ). To identify the isolates, universal primers ITS1/ITS4 (White et al. 1993) were used for polymerase chain reaction–based molecular identification. The amplification region was sequenced by Sangon Biotech (Shanghai, China) and submitted to GenBank (MW819983). BLAST analysis showed that the sequence was 100% identical to Pythium aphanidermatum. Pathogenicity tests were conducted 3 times, with 4 treatments and 2 controls each time. The plants treated were 6 months old. Then the hyphae growing on PDA for 7 days were cut into four pieces. Next, they were inoculated into the soil of the A. manihot. Negative control was inoculated only with PDA for 7 days ( Zhang et al. 2000). The plants were then placed in a greenhouse under 28°C, 90% relative humidity. After inoculated 20 to 30 days, the infected plants showed stalk rot, the same symptoms as observed on the original plants. The control plants didn’t display symptoms. Pythium aphanidermatum was re-isolated from infected stems and showed the same characteristics as described above and was identical in appearance to the isolates used to inoculate the plants. To our knowledge, this is the first report of Pythium aphanidermatum infecting A. manihot stem and causing stalk rot in China. It may become a significant problem for A. manihot. Preliminary management practices are needed for reducing the cost and losses of production.

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First Report of Fusarium incarnatum-equiseti Species Complex Associated with Stalk Rot Disease of Eucommia ulmoides in China

Plant Disease ◽

10.1094/pdis-01-20-0134-pdn ◽

2020 ◽

Vol 104 (12) ◽

pp. 3256

Author(s):

Xinmei Fang ◽

Fengying Luo ◽

Zeyu Zhang ◽

Tianhui Zhu ◽

Shan Han ◽

...

Keyword(s):

Species Complex ◽

Eucommia Ulmoides ◽

First Report ◽

Stalk Rot ◽

Rot Disease

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First report of corn stalk rot caused by Dickeya zeae on sweet corn in Shanghai, China

Journal of Plant Pathology ◽

10.1007/s42161-019-00447-8 ◽

2019 ◽

Vol 102 (2) ◽

pp. 557-558

Author(s):

Yuan Guan ◽

Wen Chen ◽

Yuxin Wu ◽

Yingxiong Hu ◽

Hui Wang ◽

...

Keyword(s):

Sweet Corn ◽

Corn Stalk ◽

First Report ◽

Stalk Rot

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First report of fruit blight caused by Alternaria alternata on sesame in Northeast China

Plant Disease ◽

10.1094/pdis-01-21-0047-pdn ◽

2021 ◽

Author(s):

Hongsen Cheng ◽

De Xue Gao ◽

Huijie Sun ◽

Yanbin Na ◽

Jing Xu

Keyword(s):

Alternaria Alternata ◽

Morphological Characteristics ◽

Its Region ◽

Liaoning Province ◽

Oilseed Crop ◽

Distilled Water ◽

Conidial Suspension ◽

First Report ◽

Health Products ◽

Blight Disease

Sesame (Sesamum indicum L.) is an important oilseed crop in China and it is also used in food and health products. In August of 2019, a blight sesame fruit was observed in a field of Liaoyang city, Liaoning province of China. Initial disease symptoms consisted of brown or dark brown spots on fruit. With time, lesions coalesced and the whole fruit turned dark brown or black. Most of the diseased fruit had thin and small, deformed, necrotic, hardened cracked epidermal lesions. Lesions were also produced on stem and petioles leading to leaf abscission. The disease results in premature fruit death, and in turn, considerable yield losses. To determine the causal agent, symptomatic fruit with developing lesions were collected, and surface sterilized in 2% NaClO for 3 min, rinsed three times in distilled water, and plated onto PDA medium. After incubation at 25°C for 5 days, a dark olivaceous fungus with abundant, branched, brown to black, and septate hyphae was consistently isolated. Twenty single spores were separated with an inoculation needle under stereomicroscope. The conidia were in chains, brown, obclavate, ovoid or ellipsoid, with 1-6 transverse septa and 0-4 longitudinal or oblique septa 12.5 to 45 × 6.5 to 14.5 μm in size. Conidiophores were septate, light brown to olive brown, measuring 22-60 μm × 2-4 μm. The morphological characteristics of the 20 isolates all matched the description of Alternaria alternata (Simmons, 2007). The internal transcribed spacer (ITS) region of rDNA of 15 isolates was amplified using primers ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone et al. 1999) and sequenced. Identical sequences were obtained and the sequence of the isolate ZMHG12 was submitted to GenBank (Accession no. MW418181 and MW700316). BLAST analysis of the sequences of the isolates of ZMHG12 showed 100% to A. alternata (KP739875 and LC132712). In pathogenicity tests, a conidial suspension (2.5 × 105 conidia per ml) was prepared from 7 days-old cultures of isolate ZMHG12 grown on PDA at 25°C. Fruit of 10 two-month-old potted sesame plants (Variety “Liaozhi 8”) were sprayed with the conidia suspension until runoff. Another 10 plants sprayed with distilled water to served as non-inoculated controls. All plants were maintained for 48 h in a humid chamber with a temperature of 25°C to 26°C, and then moved to a greenhouse. Ten days after inoculation, all fruit of inoculated plants exhibited symptoms similar to those observed in the field and non-inoculated control plants remained symptomless. The experiment was repeated twice with similar results. A. alternata has been reported as a pathogen caused leaf blight disease of sesame in Pakistan (Nayyar et al. 2017). To our knowledge, this is the first report of A.alternata causing fruit blight of sesame in China. To date, we have observed the disease on sesames in fields of Fuxin, Chaoyang and Tieling city in Liaoning Province, and Tongliao city in Inner Mongolia of China, and it has become an important disease in sesame production of China. References : Simmons E. G. 2007. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands. White T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone I., et al. 1999. Mycologia, 91: 553-556. Nayyar, B. G., et al. 2017. Plant Pathology Journal, 33 (6): 543-553.

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First Report of Fusarium culmorum Causing Maize Stalk Rot in China

Plant Disease ◽

10.1094/pdis-07-21-1442-pdn ◽

2021 ◽

Author(s):

Laikun Xia ◽

Yanyong Cao ◽

Jie Wang ◽

Jie Zhang ◽

Shengbo Han ◽

...

Keyword(s):

Fusarium Species ◽

Apical Cell ◽

Fusarium Culmorum ◽

Aerial Mycelium ◽

Henan Province ◽

Population Diversity ◽

Pathogenicity Test ◽

Ear Rot ◽

First Report ◽

Stalk Rot

Maize stalk rot has become one of the most important diseases in maize production in China. From 2017 to 2019, a survey was conducted to determine the population diversity of Fusarium species associated with maize diseases in 18 cities across Henan Province. Maize stalk rot with an incidence of more than 20% that caused yield losses up to 30% was observed on maize variety Zhengdan958, which was grown in two continuous maize fields in Zhumadian City, Henan Province. The stem tissues from the boundary between diseased and healthy pith were chopped into small pieces (3 × 8 mm), disinfected (70% ethanol for 1 min) and then placed onto potato dextrose agar (PDA) amended with L-(+)-Lactic-acid (1 g/L) and incubated at 25°C for 4 days. Colonies on PDA produced fluffy, light yellow aerial mycelium and purple to deep brick red pigment at 25°C (Fig 1A, 1B). On carnation leaf agar (CLA), macroconidia in orange sporodochia formed abundantly, but microconidia were absent. Macroconidia were short and thick-walled, had 3 to 5 septa, a poorly developed foot cell and rounded apical cell (Fig 1C). These characteristics matched the description of Fusarium culmorum (Leslie and Summerell 2006) and isolates DMA268-1-2 and HNZMD-12-7 were selected for further identity confirmation. Species identification was confirmed by partial sequences of three phylogenic loci (EF1-α, RPB1, and RPB2) using the primer pairs EF1/EF2, CULR1F/CULR1R, and CULR2F/CULR2R, respectively (O'Donnell et al., 1998). The consensus sequences from the two isolates were deposited in GenBank (MZ265416 and MZ265417 for TEF, respectively; MZ265412 and MZ265414 for RPB1, respectively; MZ265413 and MZ265415 for RPB2). BLASTn searches indicated that the nucleotide sequences of the three loci of the two isolates revealed 99% to 100% similarity to those of F. culmorum strains deposited in the GenBank, Fusarium-ID, and MLST databases (Supplementary Table 1~3). Pathogenicity test was conducted at the flowering-stage using Zhengdan958 and Xundan20 plants according to previously described method (Zhang et al., 2016; Cao et al., 2021; Zhang et al., 2021). The second or third internodes of thirty flowering plants were drilled to make a wound approximately 8 mm in diameter using an electric drill. Approximately 0.5 mL inoculum (125 mL colonized PDA homogenized with 75 mL sterilized distilled water) was injected into the wound and sealed with Vaseline and Parafilm to maintain moisture and avoid contamination. Sterile PDA slurry was used as a control. Thirty days after inoculation, the dark-brown, soft rot of pith tissues above and below the injection sites were observed, and some plants were severely rotten and lodged (Fig 1D, 1E). These symptoms were similar to those observed in the field. No symptoms were observed on control plants. The same pathogen was re-isolated from the inoculated stalk lesions but not from the control, thereby fulfilling Koch's postulates. To our knowledge, this is the first report of F. culmorum as the causal agent of stalk rot on maize plants in China. Also, this fungus has been reported to cause maize ear rot in China (Duan et al. 2016) and produce mycotoxins such as trichothecenes, nivalenol, and zearalenone that cause toxicosis in animals (Leslie and Summerell 2006). The occurrence of maize stalk rot and ear rot caused by F. culmorum should be monitored due to the potential risk for crop loss and mycotoxin contamination.

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First Report of Bacterial Stalk Rot of Maize Caused by Dickeya zeae in Mexico

Plant Disease ◽

10.1094/pdis-02-14-0198-pdn ◽

2014 ◽

Vol 98 (9) ◽

pp. 1267-1267 ◽

Cited By ~ 4

Author(s):

B. A. Martinez-Cisneros ◽

G. Juarez-Lopez ◽

N. Valencia-Torres ◽

E. Duran-Peralta ◽

M. Mezzalama

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Pathogenic Bacteria ◽

The State ◽

Rrna Gene ◽

Bacterial Disease ◽

Sterile Water ◽

First Report ◽

Stalk Rot ◽

Positive Controls

A bacterial disease of maize, bacterial stalk and top rot, was found in the state of Morelos in February 2011, and in the state of Puebla in July 2013, Mexico. In both cases, the incidence of diseased plants was lower than 0.5%. The typical symptoms were a soft rot and darkening of the tissues affecting the stalk and the top of the plant, causing breaking of the stalk. The lesions progressed from the top to below nodes, leaf sheaths and blades, and rotten tissues emitted an unpleasant odor. Eleven diseased plants were collected, and bacterial colonies were isolated from fragments detached from the edges of symptomatic tissues after sterilization with a 0.5% solution of NaClO for 30 s, rinsing three times in sterile water. The sterilized fragments were macerated in drops of distilled sterile water for 10 min and the extract was streaked on King's medium B (agar 15 g, distilled water 1,000 ml, proteose peptone 20 g, K2HPO4 1.5 g, MgSO4·7H2O 1.5 g, glycerol 10 ml). Eight representative strains from Morelos and five from Puebla were selected for identification. All strains were gram-negative, grew at 37°C, showed pectynolitic activity on potato tubers, were positive for indole production, utilized arabinose, galactose, glucose, glycerol, lactose, mannose, melibiose, rafinose, ribose, and sucrose but did not produce acid from arabitol, adonitol, and keto-methyl-glucoside (3,4). Pathogenicity tests were conducted with each strain by inoculating with a syringe four 25-day-old maize seedlings with 107 CFU ml–1 bacterial cells in the leaf collar. Plants were incubated in the greenhouse at 30°C during the day and 24°C during the night with a 12-h photoperiod, and relative humidity of 93%. The reference strains Erwinia chrysanthemi pv zeae ATTC29942 and Dickeya zeae CFBP 2052 were used as positive controls in laboratory and greenhouses tests. Sterile water was used as negative control. Two days after inoculation, soft stalk rot symptoms developed that were identical to those observed in the field. No symptoms were observed on the negative controls. Diagnostic amplification of DNA by conventional PCR was carried out and yielded the expected amplicon size of 420 bp of the Dickeya-specific pel gene with the ADE primers set (2). PCR was used to amplify the 16S rRNA gene with the universal primers 27f and 1495r (5) for molecular identification of the 13 strains (GenBank Accession Nos. KJ438941, KJ438942, KJ438943, KJ438944, KJ438945, KJ438946, KJ438947, KJ438948, KJ438949, KJ438950, KJ438951, KJ438952, and KJ438953). The strains D. zeae CFBP 2052 and E. chrysanthemi pv. zeae ATCC 29942 were sequenced as positive controls. A BLAST search with the 13 16S rRNA gene sequences of 1.4 kb were 99% identical to the sequence of D. zeae CFBP 2052 (NR_041923). D. zeae can be a major disease of maize in tropical and subtropical countries. It is particularly severe under conditions of high temperature and high humidity, but it occurs sporadically. Control of the vector, Chilo partellus, can aid disease management (1). To our knowledge, this is the first report of D. zeae causing maize stalk rot in Mexico. References: (1) CABI. Crop Prot. Compend. CAB International, Wallingford, UK, 2014. (2) A. Nassar et al. Appl. Environ. Microbiol. 62:2228, 1996. (3) R. Samson et al. Int. J. Syst. Evol. Microbiol. 55:1415, 2005. (4) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. APS Press, St. Paul, MN, 2001. (5) W. G. Weisburg. J. Bacteriol. 173:697, 1991.

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First Report of Valsa leucostoma Causing Valsa Canker of Pyrus communis (cv. Duchess de' Angouleme) in China

Plant Disease ◽

10.1094/pdis-07-13-0704-pdn ◽

2014 ◽

Vol 98 (3) ◽

pp. 422-422 ◽

Cited By ~ 1

Author(s):

M. X. Zhang ◽

L. F. Zhai ◽

W. X. Xu ◽

N. Hong ◽

G. P. Wang

Keyword(s):

Pyrus Communis ◽

Liaoning Province ◽

Post Inoculation ◽

Internal Transcribed Spacer Region ◽

Canker Disease ◽

First Report ◽

Agar Plug ◽

Valsa Canker ◽

Pear Trees ◽

Β Tubulin

Pear is a popular fruit in the world market, and has been widely cultivated in China. Since 2008, a severe canker disease has consistently been observed on 20-year-old pear trees (Pyrus communis cv. Duchess de' Angouleme) grown in a nursery in Xingcheng, Liaoning Province, China. Observed symptoms include brown elongated ulcerative lesions (more than 20 cm in length in general), with red brown conidia produced on wet lesions. Reductions in tree vigor and yield were observed for infected trees. Tree mortality was observed for severe infections. To diagnose the pathogen, 15 canker samples were collected from five pear trees in April, 2012. Bark pieces (3 to 5 mm) taken from the border of healthy and diseased tissue were surface-disinfected with 0.1% mercury bichloride and 75% ethanol for 45 s, and placed on potato dextrose agar (PDA) medium at 25°C in darkness. Fungal colonies with a common colony morphology were consistently recovered from three samples. These fungal colonies were initially white, becoming olive green in 3 days. Conidia produced on colonies were hyaline, allantoid, and single-celled with average length × width of 6.04 (5.43 to 6.59) × 0.65 (0.51 to 0.73) μm, which were consistent with descriptions of Valsa leucostoma (1). Genomic DNA was extracted from a representative isolate F-LN-32b, and subjected to PCR amplification of the internal transcribed spacer region (ITS), β-tubulin gene, and EF1 gene using the primer pairs ITS1/ITS4, Bt2a/Bt2b and EF1-728F/EF1-986R (3), respectively. Sequence alignment of the amplified fragments with the deposited data in NCBI showed that sequences of EF1, ITS, and β-tubulin (GenBank Accession No. KF293296 to KF293298, respectively) of isolate F-LN-32b had the highest similarity of 99% to those of V. leucostoma strain 32-2w (JQ900340, JN584644, and JQ900374), and suggested that isolate F-LN-32b is a V. leucostoma strain. Pathogenicity tests was carried out by placing a 5-mm-diameter, 2-day-old mycelium agar plug of isolate F-LN-32b onto a punched bark hole of a detached 1-year-old pear shoot after it was surface disinfested with ethanol. Inoculated shoots were incubated at 25°C in plastic containers covered with plastic film. Pathogenicity assays were conducted on 18 pear varieties (cvs. Qiuyue, Jinshui 2, Hohsui, Huali 1, Cuiguan, Shinseiki, Xuehua, Dangshansu, Zaosu, Hongxiangsu, Yuluxiang, Nanguoli, Xizilv, Bartlett, Huanghua, Huashan, Duchess de' Angouleme, and Packham's) collected from a nursery in Wuhan, Hubei Province, China. Six shoots were inoculated for each variety and the assay was conducted three times. All inoculated shoots developed the typical canker symptoms after 6 days post inoculation (dpi) and sporulated at 25 dpi while the control shoots inoculated with non-colonized PDA plugs remained asymptomatic. Isolates recovered from inoculated samples were of the same morphology and ITS sequence as F-LN-32b. Based on these results, V. leucostoma was determined as the pathogen responsible for the Valsa canker disease on pear. Valsa mali var. pyri was identified as the only pathogen causing Valsa canker disease on pear in China (2). To our knowledge, this is the first report of V. leucostoma causing a canker disease on pear in China. References: (1) G. C. Adams et al. Australas. Plant Pathol. 35:521, 2006. (2) X. L. Wang et al. Mycologia 103:317, 2011. (3) T. J. White et al. Pages 315-322 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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