First Report of Fruit Rot Caused by Fusarium luffae in Muskmelon in China

Muskmelon (Cucumis melo L.) is one of the most widely cultivated and economically important fruit crops in the world. However, many pathogens can cause decay of muskmelon fruit, including Fusarium spp.. Fusarium spp. are the most important pathogen, affecting muskmelon fruit yield and quality (Wang et al. 2011). In August 2020, fruit rot symptoms were observed on ripening muskmelons (cv. Tianbao) in several fields in Jiyang District, Jinan City of Shandong Province, China. The incidences of infected muskmelon ranged from 15% to 30% and caused an average 20% yield loss. Symptoms appeared as pale brown, water-soaked lesions that were irregular in shape, with the lesion sizes ranging from a small spot (1 to 2 cm) to decay of the entire fruit. The core and surface of infected fruit were colonized and covered with white mycelia. Two infected muskmelons were collected from two fields, 3.5 km apart. Tissues removed from inside the infected fruit were surface disinfected with 75% ethanol for 30 s, and cultured on potato dextrose agar (PDA) at 25°C in the dark for 5 days. Four purified cultures were obtained using the single spore method. On carnation leaf agar (CLA), 3 to 5 septate, falcate, with a pronounced dorsiventral curvature macroconidia with tapered apical cell, and foot-shaped basal cell, measuring 20 to 40 × 3.5 to 4.5 μm. Microconidia and chlamydospores were not observed. These morphological characteristics were consistent with the description of F. luffae (Wang et al., 2019). Because these isolates had similar morphology, two representative isolates (XP11 and XP12) were selected for multilocus phylogenetic analyses. DNA was extracted from the representative isolates using a CTAB method. Nucleotide sequences of the internal transcribed spacers (ITS) (White et al. 1990), calmodulin (CAM), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-α gene (TEF1) (Xia et al. 2019) were amplified using specific primers, sequenced, and deposited in GenBank (ITS: MW391509 and MW391510, CAM: MW392789 and MW392790, RPB2: MW392797 and MW392798, TEF1: MW392793 and MW392794). Alignments of a combined dataset of ITS, CAM, RPB2 and TEF1 were made using MAFFT v. 7, and phylogenetic analyses were conducted in MEGA v. 7.0 using the maximum likelihood method. The muskmelon isolates (XP11 and XP12) clustered together with the F. luffae reference strain LC12167 (99% bootstrap). To perform a pathogenicity test, 10 μl of conidial suspensions (1 × 106 conidia/ml) were injected into each muskmelon fruit using a syringe, and the control fruit was inoculated with 10 μl of sterile distilled water. There were ten replicated fruits for each treatment. The test was repeated three times. After 7 days at 25°C, the interior of the inoculated muskmelons begun to rot, and the rot lesion expanded from the core towards the surface of the fruit, then white mycelia were produced on the surface. Ten isolations were re-isolated from the infected tissues and confirmed to fulfill Koch’s postulates. No symptoms were observed on the control muskmelons. To our knowledge, this is the first report of fruit rot caused by F. luffae in muskmelon in China. Considering the economic value of the muskmelon crop, correct identification can help farmers select appropriate field management measures for control of this disease.

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First Report of Fusarium pernambucanum Causing Fruit Rot of Muskmelon in China

Plant Disease ◽

10.1094/pdis-07-21-1520-pdn ◽

2021 ◽

Author(s):

Xianping Zhang ◽

Jiwen Xia ◽

Jiakui Liu ◽

Dan Zhao ◽

Lingguang Kong ◽

...

Keyword(s):

Phylogenetic Analyses ◽

Apical Cell ◽

Morphological Characteristics ◽

Fruit Rot ◽

Likelihood Method ◽

Correct Identification ◽

Pathogenicity Test ◽

First Report ◽

The Core ◽

Representative Isolate

Muskmelon (Cucumis melo L.) is one of the most widely cultivated and economically important fruit crops in the world. However, many pathogens can cause decay of muskmelons; among them, Fusarium spp. is the most important pathogen, affecting fruit yield and quality (Wang et al. 2011). In May 2017, fruit rot symptoms were observed on ripening muskmelons (cv. Jipin Zaoxue) in several fields in Liaocheng of Shandong Province, China. Symptoms appeared as brown, water-soaked lesions, irregularly circular in shape, with the lesion size ranging from a small spot (1 to 2 cm) to the decay of the entire fruit. The core and the surface of the infected fruit were covered with white to rose-reddish mycelium. Two infected muskmelons were collected from each of two fields, 10 km apart. Tissues from the inside of the infected fruit were surface disinfected with 75% ethanol for 30 s, and cultured on potato dextrose agar (PDA) at 25 °C in the dark for 5 days. Four purified cultures were obtained using the single spore method. On carnation leaf agar (CLA), macroconidia had a pronounced dorsiventral curvature, falcate, 3 to 5 septa, with tapered apical cell, and foot-shaped basal cell, measuring 19 to 36 × 4 to 6 μm. Chlamydospores were abundant, 5.5–7.5 μm wide, and 5.5–10.5 μm long, ellipsoidal or subglobose. No microconidia were observed. These morphological characteristics were consistent with the descriptions of F. pernambucanum (Santos et al. 2019). Because these isolates had similar morphology, one representative isolate was selected for multilocus phylogenetic analyses. DNA was extracted from the representative isolate using the CTAB method. The nucleotide sequences of the internal transcribed spacers (ITS) (White et al. 1990), translation elongation factor 1-α gene (TEF1), RNA polymerase II second largest subunit gene (RPB2), calmodulin (CAM) (Xia et al. 2019) were amplified using specific primers, sequenced, and deposited in GenBank (MN822926, MN856619, MN856620, and MN865126). Based on the combined dataset of ITS, TEF1, RPB2, CAM, alignments were made using MAFFT v. 7, and phylogenetic analyses were processed in MEGA v. 7.0 using the maximum likelihood method. The studied isolate (XP1) clustered together with F. pernambucanum reference strain URM 7559 (99% bootstrap). To perform pathogenicity test, 10 μl of spore suspensions (1 × 106 conidia/ml) were injected into each muskmelon fruit using a syringe, and the control fruit was inoculated with 10 μl of sterile distilled water. There were ten replicated fruits for each treatment. The test was repeated three times. After 7 days at 25 °C, the interior of the inoculated muskmelons begun to rot, and the rot lesion was expanded from the core towards the surface of the fruit, then white mycelium produced on the surface. The same fungus was re-isolated from the infected tissues and confirmed to fulfill the Koch’s postulates. No symptoms were observed on the control muskmelons. To our knowledge, this is the first report of F. pernambucanum causing of fruit rot of muskmelon in China. Considering the economic value of the muskmelon crop, correct identification can help farmers select appropriate field management measures for control of this disease.

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First Report of Fruit Rot of Pumpkin Caused by Fusarium solani f. sp. cucurbitae in Arkansas

Plant Disease ◽

10.1094/pdis-93-6-0669b ◽

2009 ◽

Vol 93 (6) ◽

pp. 669-669 ◽

Cited By ~ 1

Author(s):

V. L. Castroagudin ◽

J. C. Correll ◽

R. D. Cartwright

Keyword(s):

Fusarium Solani ◽

Disease Incidence ◽

Apical Cell ◽

Causal Agent ◽

Fruit Rot ◽

Monthly Precipitation ◽

Pathogenicity Test ◽

Fusarium Spp ◽

First Report ◽

Fusarium Sp

During 2008, fruit rot of pumpkin (Cucurbita pepo L.) occurred on several cultivars in commercial fields in northeast and northwest Arkansas. Disease incidence ranged from 50 to 75% of the fruit, which were unmarketable. Symptoms included large (>10 cm), brown, corky lesions where the fruit was in contact with the soil. Initially, the lesions were water soaked. A cross section of the symptomatic fruit rind revealed a dry, brown, spongy rot with a light brown halo. Lesions finally became soft and wet, causing infected fruit to collapse. Masses of white mycelia surrounded advanced lesions. No rot symptoms were observed on the vines. Fusarium spp. were isolated from symptomatic fruit. Macroconidia obtained from field-infected fruit and pure potato dextrose agar (PDA) cultures of the predominant Fusarium sp. were morphologically similar. The straight, cylindrical, and robust macroconidia contained between five and seven septa. The apical cell was rounded and blunt and the basal cell was rounded. All three morphological types were tested for pathogenicity on mature fruit of cv. Sorcerer. Fruit were surface disinfected in 70% ethanol. Wounds were made (4 mm deep) in the fruit surface with a cork borer. Three wounds per isolate per fruit were inoculated with a PDA plug colonized with mycelium from a 3-day-old culture. Three replicated wounds were inoculated per isolate and four replicate fruit were used. After inoculation, the wounds were covered with saran wrap. The fruit were incubated at approximately 24°C and evaluated after 7 days. An uncolonized PDA plug was used as a negative control. After 7 days, only the predominant Fusarium sp. produced typical lesions, which were brown, water soaked, and approximately 3 cm in diameter. Fusarium spp. were recovered from the inoculated lesions. The colonies on PDA and macroconidia of the pathogenic Fusarium sp. were morphologically similar to the isolate inoculated and the ones recovered from field lesions. DNA was extracted from the same three isolates used in the pathogenicity test. A portion of the translation elongation factor 1α (TEF) gene was sequenced to verify the identity of the pathogenic isolates. On the basis of a comparison of the Fusarium-ID database at Pennsylvania State University (3), the pathogenic isolates had a 100% match with Fusarium solani f. sp. cucurbitae race 1, teleomorph Nectria haematococca mating population I, isolate NRRL 22098. F. solani f. sp cucurbitae was previously identified as the causal agent of crown and foot rot and a fruit rot of cucurbits and responsible for outbreaks on pumpkin fruit in Connecticut, Missouri, New York, and Ohio from 2001 to 2003 and again in Ohio in 2005 (2). In 2008, a higher average total of monthly precipitation was recorded late in the growing season in Arkansas, (13.7 cm in August and 23.7 cm in September). Although F. equiseti has previously been reported as a fruit rot pathogen of pumpkin in Arkansas (1), to our knowledge, this is the first report of F. solani f. sp cucurbitae as causal agent of pumpkin fruit rot in the state. Reference: (1) J. C. Correll et al. Plant Dis. 75:751, 1991. (2) W. H. Elmer et al. Plant Dis. 91:1142, 2007. (3) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004.

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First Report of Postharvest Fruit Rot Disease of Yellow Peach Caused by Diaporthe eres in China

Plant Disease ◽

10.1094/pdis-11-21-2484-pdn ◽

2021 ◽

Author(s):

Yusen Xiao ◽

Guanghua Huo ◽

Lili Liu ◽

Chunxi Yang ◽

Chaoyu Cui

Keyword(s):

Management Practices ◽

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Its Region ◽

Fruit Rot ◽

Economic Losses ◽

Pathogenicity Test ◽

Transparent Plastic ◽

First Report ◽

Agar Disc

The yellow peach (Amygdalus persica), is a fruit crop native to China with golden peel and pulp that is of particular interest in the fruit markets. In August of 2021, yellow peaches showing fruit rot symptoms were purchased from a commercial market in Linyi city, Shandong province, China. The symptoms included circular, tan to brown in color, rotten, necrotic lesions, and whitish mycelium mass in the center of the lesions. The infected fruit were surface disinfected with 1% NaClO for 30 s and rinsed with sterile distilled water three times. Diseased tissues from the infected fruits were cut into small segments, aseptically shifted onto potato dextrose agar media containing petri plates and incubated at 25℃ for 5 days. Eight isolates were obtained in total from two isolation experiments. Fungal colonies were initially white, aerial, fluffy at first, and gradually turned brown to gray, with black stromata at maturity. Alpha conidia were aseptate，hyaline，fusiform to ellipsoidal，and ranged in size from 4.16 to 7.76 µm × 1.95 to 3.14 µm (n=30). Beta conidia were aseptate, hyaline, filiform, curved to hamate, and 15.91 to 22.55 µm × 0.82 to 1.66 µm (n=30). The morphological characteristics were consistent with those of Diaporthe species (Gomes et al. 2013). For further identification, a multigene phylogenetic analysis was carried out. The internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α), histone H3 (HIS), calmodulin (CAL), and β-tubulin (TUB) genes of two representative isolates were amplified by using primers ITS1/ITS4, EF1-728F/EF1-986R, CYLH3F/H3-1b，CAL228F/CAL737R, and Bt2a/Bt2b (Chaisiri et al. 2021), respectively. The sequences were deposited in GenBank (Accession No. OL375154 for ITS; OL406409 for TEF1-α; OL406410 for HIS; OL106407 for CAL; OL406408 for TUB). phylogenetic analyses were conducted using the concatenation of multiple sequences (ITS, TEF1-α, HIS, CAL, TUB) with Maximum Likelihood (ML) in IQtree v1.5.6 (Nguyen et al. 2015). Based on the morphological and phylogenetic characters, the isolates were identified as D. eres. A Pathogenicity test was performed by wound inoculation on harvested fruits of A. persica Variety ‘Jinxiu’. Mature and healthy yellow peaches purchased from Shandong, Anhui, and Hunan Provinces in China were surface sterilized with 1% NaClO solution for 1 minute, rinsed with sterile water and dried. Each fruit was wounded with a sterile scalpel creating a 2-3 mm incision on the peel. A 5 mm agar disc with mycelium grown on PDA at 28℃ for 7 days was placed on wound and sealed with parafilm. Sterile PDA plugs were used as controls. Ten fruit were used for each treatment and the assays were repeated three times. Inoculated fruit were placed in sterilized transparent plastic cans containing wet, sterile paper towels. After 5 days of incubation at 25℃, the same rot symptoms were observed on fruits inoculated with mycelium and the control remained symptomless. D. eres was re-isolated from the lesions of inoculated fruits and the pathogen identification was confirmed by molecular analysis, thus fulfilling complete Koch’s postulates. Although D. eres was previously reported on peach trees of causing shoot blight (Thomidis and Michailides 2009) and stem canker (Prencipe et al. 2017). To our knowledge, this is the first report of D. eres causing postharvest fruit rot of yellow peach in China and it may lead to considerable economic losses in the peach industry should post-harvest disease management practices not be implemented.

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First Report of Bipolaris oryzae Causing Leaf Spot on Cultivated Wild Rice (Oryza rufipogon) in China

Plant Disease ◽

10.1094/pdis-11-20-2529-pdn ◽

2021 ◽

Author(s):

Yue Lian Liu ◽

Jian Rong Tang ◽

Ya Li ◽

Hong Kai Zhou

Keyword(s):

Leaf Spot ◽

Wild Rice ◽

Morphological Characteristics ◽

Oryza Rufipogon ◽

Likelihood Method ◽

Leaf Spot Disease ◽

Pathogenicity Test ◽

Sterile Water ◽

Bipolaris Oryzae ◽

First Report

Wild rice (Oryza rufipogon) has been widely studied and cultivated in China in recent years due to its antioxidant activities and health-promoting effects. In December 2018, leaf spot disease on wild rice (O. rufipogon cv. Haihong-12) was observed in Zhanjiang (20.93 N, 109.79 E), China. The early symptom was small purple-brown lesions on the leaves. Then, the once-localized lesions coalesced into a larger lesion with a tan to brown necrotic center surrounded by a chlorotic halo. The diseased leaves eventually died. Disease incidence was higher than 30%. Twenty diseased leaves were collected from the fields. The margin of diseased tissues was cut into 2 × 2 mm2 pieces, surface-disinfected with 75% ethanol for 30 s and 2% sodium hypochlorite for 60 s, and then rinsed three times with sterile water before isolation. The tissues were plated on potato dextrose agar (PDA) medium and incubated at 28 °C in the dark for 4 days. Pure cultures were produced by transferring hyphal tips to new PDA plates. Fifteen isolates were obtained. Two isolates (OrL-1 and OrL-2) were subjected to further morphological and molecular studies. The colonies of OrL-1 and OrL-1 on PDA were initially light gray, but it became dark gray with age. Conidiophores were single, straight to flexuous, multiseptate, and brown. Conidia were oblong, slightly curved, and light brown with four to nine septa, and measured 35.2–120.3 µm × 10.3–22.5 µm (n = 30). The morphological characteristics of OrL-1 and OrL-2 were consistent with the description on Bipolaris oryzae (Breda de Haan) Shoemaker (Manamgoda et al. 2014). The ITS region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and translation elongation factor (EF-1α) were amplified using primers ITS1/ITS4, GDF1gpp1/GDR1 gdp2 (Berbee et al. 1999), and EF-1α-F/EF-1α-R EF-1/EF-2 (O’Donnell 2000), respectively. Amplicons of OrL-1 and OrL-2 were sequenced and submitted to GenBank (accession nos. MN880261 and MN880262, MT027091 and MT027092, and MT027093 and MT027094). The sequences of the two isolates were 99.83%–100% identical to that of B. oryzae (accession nos. MF490854，MF490831，MF490810) in accordance with BLAST analysis. A phylogenetic tree was generated on the basis of concatenated data from the sequences of ITS, GAPDH, and EF-1α via Maximum Likelihood method, which clustered OrL-1 and OrL-2 with B. oryzae. The two isolates were determined as B. oryzae by combining morphological and molecular characteristics. Pathogenicity test was performed on OrL-1 in a greenhouse at 24 °C to 30 °C with 80% relative humidity. Rice (cv. Haihong-12) with 3 leaves was grown in 10 pots, with approximately 50 plants per pot. Five pots were inoculated by spraying a spore suspension (105 spores/mL) onto leaves until runoff occurred, and five pots were sprayed with sterile water and used as controls. The test was conducted three times. Disease symptoms were observed on leaves after 10 days, but the controls remained healthy. The morphological characteristics and ITS sequences of the fungal isolates re-isolated from the diseased leaves were identical to those of B. oryzae. B. oryzae has been confirmed to cause leaf spot on Oryza sativa (Barnwal et al. 2013), but as an endophyte has been reported in O. rufipogon (Wang et al. 2015).. Thus, this study is the first report of B. oryzae causing leaf spot in O. rufipogon in China. This disease has become a risk for cultivated wild rice with the expansion of cultivation areas. Thus, vigilance is required.

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First Report of Leaf Spots caused by Nigrospora oryzae on Wild Rice in China

Plant Disease ◽

10.1094/pdis-11-20-2522-pdn ◽

2021 ◽

Author(s):

Yue Lian Liu ◽

Jian Rong Tang ◽

Ya Li ◽

Hong Kai Zhou

Keyword(s):

Leaf Spot ◽

Wild Rice ◽

Morphological Characteristics ◽

Oryza Rufipogon ◽

Its Sequences ◽

Likelihood Method ◽

Pathogenicity Test ◽

Sterile Water ◽

First Report ◽

Nigrospora Oryzae

In recent years, wild rice (Oryza rufipogon Griff) has been widely cultivated because of its health-promoting effects. In May 2019, leaf spot lesions on cv. Haihong-12 were observed in Zhanjiang (20.93N, 109.79E), China. Leaf symptoms were yellow-to-brown, oval or circular with a very distinctive, large yellow halo. Black spores appeared on the leaves with advanced symptoms. The lesions coalesced, causing the entire leaf to become blighted and die. Disease incidence reached approximately 10% in the fields (8 ha) surveyed. Twenty leaves with symptoms were collected and cut into pieces of 2 ×2 cm in size. They were surface-disinfected with 75% ethanol for 30 s and 2% sodium hypochlorite (NaOCl) for 60 s, rinsed three times with sterile water, blotted dry on sterile paper, plated on potato dextrose agar (PDA) medium, and incubated at 28°C in the dark for 4 days. Ten pure cultures were obtained by transferring hyphal tips to new PDA plates, and monosporic cultures were obtained from three isolates (Nos-1, Nos-2, and Nos-3). Those isolates exhibited very similar morphological characteristics on PDA. Colony of isolate Nos-1 was white at the early stage and became dark gray after 7 days. Conidia were produced from clusters of conidiophores, single celled, black, smooth, spherical, and 9.5 to 14.2 µm (average 10.6 µm ± 0.42) in diameter. Morphological characteristics of the isolates matched the description of Nigrospora oryzae Petch (Wang et al. 2017). The ITS region was amplified using primers ITS1 and ITS4 (White et al. 1990). Nucleotide sequences of isolates Nos-1, Nos-2, and Nos-3 deposited in GenBank under acc. nos. MW042173, MW042174, and MW042175, respectively, were 100% identical to N. oryzae (acc. nos. KX985944, KX985962; and KX986007). A phylogenetic tree generated based on the ITS sequences and using a Maximum Likelihood method with 1,000 bootstraps showed that these three isolates from wild rice were grouped with other N. oryzae isolates downloaded from GenBank (bootstrap = 100%) but away from other Nigrospora spp. Pathogenicity test was performed with these three isolates in a greenhouse at 24 to 30°C. Approximately 50 seedling of wild rice cv. Haihong-12 were grown in each pot. At the 3-leaf stage, plants in three pots were inoculated with each isolate by spraying a spore suspension (105 spores/ml) until runoff. Three pots sprayed with sterile water served as the controls. Each 3-pot treatment was separately covered with a plastic bag. The test was conducted three times. Diseased symptoms were observed on the inoculated leaves after 10 days while no disease was observed in the control plants. Morphological characteristics and the ITS sequences of fungal isolates re-isolated from the diseased leaves were identical to those of N. oryzae. N. oryzae has been reported to cause leaf spot on O. sativa (Wang et al. 2017), but not on O. rufipogon. Thus, this is the first report of N. oryzae causing leaf spot of O. rufipogon in China. The finding provides the information important for further studies to develop management strategies for control of this disease.

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First Report of Leaf Spot of Weigela florida Caused by Epicoccum layuense in China

Plant Disease ◽

10.1094/pdis-07-20-1498-pdn ◽

2021 ◽

Author(s):

Yue Tian ◽

Yingying Zhang ◽

Chaodong Qiu ◽

Zhenyu Liu

Keyword(s):

Leaf Spot ◽

Large Subunit ◽

Morphological Characteristics ◽

Likelihood Method ◽

Pathogenicity Test ◽

Distilled Water ◽

Beta Tubulin ◽

First Report ◽

Leaf Spots ◽

Weigela Florida

Weigela florida (Bunge) A. DC. is a dense, rounded, deciduous shrub commonly planted in landscapes. It is also used in Chinese medicine to treat sore throat, erysipelas, cold, and fever (Zheng et al. 2019). In May 2019, leaf spots were observed on approximately 50% of W. florida plants grown in the Wisdom Plaza Park of Anhui Agricultural University in Hefei, Anhui Province, China. Leaf spots begun as small light brown and irregular lesions, enlarged, turned reddish brown, coalesced to form large blighted areas, and eventually covered the entire leaf surface. Five pieces of tissues were removed from the lesion margins of each diseased leaf (five leaves from five different plants), chopped into several 3-4 mm2 pieces, disinfected with 1.5% NaOCl for 2 min, rinsed 3 times with sterile distilled water for 1 min, plated onto Potato Dextrose Agar (PDA) medium containing 50 μg/ml of ampicillin and kanamycin, and incubated at 25°C with a 12-hour photoperiod for 5 days. One segment of the fungal growth from the growing edge of the colony was transferred onto a fresh PDA plate for purification and incubated under the same conditions for another 5 days. The colony morphology of one representative isolate (AAU0519) was characterized by a pale orange cushion in the center surrounded by irregular pink margin, diffusing red orange pigments into the PDA medium. Isolate AAU0519 was cultured on PDA medium for 7 days at 25°C in the dark to induce sporulation. The produced conidia were globose, subglobose to pyriform, golden brown to brown, and with a diameter of 7.7 - 23.8 μm. Both cultural and morphological characteristics suggested that isolate AAU0519 was an Epicoccum species, according to the description by Chen et al. 2017. Amplification and sequencing of the internal transcribed spacer (ITS), beta-tubulin, and 28S large subunit ribosomal RNA (LSU) gene fragments from the extracted genomic DNA of AAU0519 were performed using primer sets ITS1/ITS4 (White et al. 1990), Bt2a/Bt2b (Glass and Donaldson 1995), and LSU1Fd/LR5 (Crous et al. 2009; Vilgalys and Hester 1990), respectively. A phylogenetic tree was constructed by the maximum-likelihood method with 1,000 bootstrapping replications based on the concatenated ITS, beta-tubulin, and LSU sequences from isolate AAU0519 and representative strains of 22 species of the genus Epicoccum (Chen et al. 2017). Isolate AAU0519 clustered with ex-holotype CGMCC 3.18362 of Epicoccum layuense Qian Chen, Crous & L. Cai (Chen et al. 2017). All obtained sequences were deposited into GenBank under accession numbers MK983497 (ITS), MN328723 (beta-tubulin), and MN328724 (LSU). A pathogenicity test was conducted on leaves of five 3-year-old W. florida cultivar “Red Prince” planted in the field (five leaves for each treatment and control per plant) by spraying 30 ml of a spore suspension (106 spores/ml) of isolate AAU0519 as treatment or sterilized distilled water as control. Before the inoculation, the leaves were disinfected with 70% ethanol. After inoculation, the leaves were wrapped with a plastic bag to keep high relative humidity. The average air temperature was about 28°C during the period of pathogenicity test. The experiment was repeated once. Ten days after inoculation, the fungal-inoculated leaves developed light brown lesions resembling those of naturally infected leaves, control leaves did not develop any symptoms. E. layuense was recovered from leaf lesions and its identity was confirmed by morphological and sequence analyses as described above. To our knowledge, E. layuense has been previously reported as a pathogen of Perilla sp. (Chen et al. 2017), oat (Avena sativa) (Chen et al. 2019), and tea (Camellia sinensis) plants (Chen et al. 2020), but this is the first report of E. layuense causing leaf spot on W. florida in China. This pathogen could pose a threat to the ornamental value of W. florida plants. Thus, it is necessary to adopt effective management strategies against leaf spot on W. florida.

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First Report of Fusarium proliferatum Causing Fruit Rot of Winter Jujube (Zizyphus jujuba) in Storage in China

Plant Disease ◽

10.1094/pdis-12-11-1035-pdn ◽

2012 ◽

Vol 96 (6) ◽

pp. 913-913 ◽

Cited By ~ 3

Author(s):

M. Zhang ◽

Y. Wang ◽

C. Y. Wen ◽

H. Y. Wu

Keyword(s):

Apical Cell ◽

Morphological Characteristics ◽

Fusarium Proliferatum ◽

Fruit Rot ◽

Distilled Water ◽

First Report ◽

Pale Yellow ◽

Agar Plug ◽

Jujube Fruit ◽

Zizyphus Jujuba

Winter jujube, Zizyphus jujuba Mill., is a Chinese crop with fruit that has an extremely high nutritional value (4). In early November 2010, a severe fruit rot affecting ~20% of 1,000 kg of winter jujube fruit was observed in a storehouse in Zhengzhou, Henan province, China. The same fruit rot symptoms were found in two supermarkets in Zhengzhou in late November 2010 in ~10% of 100 kg of fruit in one supermarket and 25% of 50 kg of fruit in the other. Symptoms first appeared as small, round, pale yellow brown lesions on the fruits, 1 to 3 mm in diameter, then developed into 5- to 10-mm, sunken, brown spots, each with a pale brown margin. Three Fusarium isolates (DZF001 to DZF003) showing similar morphological characteristics were isolated from three specimens (collected from one storehouse and two supermarkets) by surface sterilizing small pieces of necrotic fruit tissue for 1 min in 2% NaOCl, washing the tissue pieces three times with sterile distilled water, and plating the pieces on potato dextrose agar (PDA). Fungal colonies for each isolate were white to light pink, and the adaxial side of each culture was pale yellow. Macroconidia were produced in pale orange sporodochia and were slender, relatively straight, three to five septa, 29.0 to 55.2 × 2.5 to 4.0 μm, with a curved apical cell and a poorly developed basal cell. Microconidia were produced in chains or false heads on synthetic nutrient-poor agar, clavate with a planar base, aseptate, and 4.5 to 8.0 × 2.5 to 3.5 μm. Conidiophores terminated in verticils of two to three phialides or monophialides. Chlamydospores were absent. The cultural and morphological characteristics were similar to those of Fusarium proliferatum (1,2). The identity of the three fungal isolates was confirmed to be F. proliferatum by DNA sequencing of the internal transcribed spacer (ITS) rDNA region (GenBank Accession Nos. JN889713 to JN889715), which were 99 to 100% homologous to those of other F. proliferatum isolates (GU066714, HQ113948, and GU363955); and the elongation factor 1-alpha (EF-1a) gene (JN889713 to JN889715), which was 99% homologous to those of other F. proliferatum isolates (FJ538244, FJ895277, and GQ848536) (3). Pathogenicity tests were conducted on 20 winter jujube fruits using a mycelial plug harvested from the periphery of a 7-day-old colony of strain DZF001, and placed on the surface of the fruit after the inoculated area of the fruit had been surface sterilized with 75% ethanol for 2 min; an equal number of fresh winter jujube fruits treated with non-colonized plugs of PDA served as the control treatment. Each jujube fruit was pricked three times with an insect needle to create three holes close together before inoculation with an agar plug. Each fruit was then enclosed in a clear plastic box with a cup of sterile distilled water to maintain high relative humidity, and held at 25°C. Symptoms similar to those originally observed on the naturally infected fruit were observed 3 days after inoculation, and the same fungus was reisolated from each of the symptomatic fruits; control fruits remained asymptomatic and no fungus was isolated from the control fruit. Koch's postulates were repeated three times with the same results. To our knowledge, this is the first report of F. proliferatum causing rot of winter jujube fruit in China. References: (1) K. Chehri et al. Saudi J. Biol. Sci. 18:341, 2011. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, Blackwell Publishing, 2006. (3) H. T. Phan. Studies Mycol. 50:261, 2004. (4) J. Sheng et al. Acta Hort. 620:203, 2003.

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First Report of Anthracnose Fruit Rot of Strawberry Caused by Colletotrichum acutatum in Montenegro

Plant Disease ◽

10.1094/pdis-02-12-0108-pdn ◽

2012 ◽

Vol 96 (7) ◽

pp. 1066-1066 ◽

Cited By ~ 1

Author(s):

J. Latinovic ◽

N. Latinovic ◽

J. Tiodorovic ◽

A. Odalovic

Keyword(s):

Morphological Characteristics ◽

Its Region ◽

Fruit Rot ◽

Colletotrichum Acutatum ◽

Pathogenicity Test ◽

Centraalbureau Voor ◽

First Report ◽

Strawberry Anthracnose ◽

Production Area ◽

Ascigerous Stage

Strawberries (Fragaria × ananassa) in Montenegro have become an increasingly important economic crop in recent years. During May 2011, severe fruit damage in strawberry cv. Clery was observed in two fields in the Podgorica region. Fruit symptoms were typical for strawberry anthracnose: sunken, dark brown to black circular lesions appeared on maturing fruits. However, no stem, crown, or foliar symptoms were observed. Under wet conditions, orange masses of conidia were produced in acervuli in the center of lesions. Conidia were hyaline, aseptate, cylindrical, with pointed ends, measuring 9.8 to 17.2 (mean 14.3) × 2.5 to 6.1 (mean 4.4) μm. Colonies on potato dextrose agar (PDA) were initially white, then turned gray as conidia formed in orange to salmon pink masses around the center of the culture. Setae or an ascigerous stage were never observed in culture or on the host. Koch's postulates were fulfilled by inoculating ripe and unripe asymptomatic fruits (20 of each, removed from strawberry plants cv. Clery) with the isolated fungus. Fruits were sprayinoculated (106 conidia/ml). An equal number of noninoculated fruits were used as a control. After incubation time of 2 to 3 days at 25°C in a moist chamber, symptoms appeared on inoculated ripe fruits. On unripe fruits, the lesions developed only 3 to 4 days after the inoculation. No symptoms were found on control fruits. The fungus was reisolated from fruits, after which typical morphological characteristics developed in culture as described above. On the basis of the symptoms, the morphological and cultural characteristics of the fungus, and the pathogenicity test, the disease was identified as strawberry anthracnose caused by Colletotrichum acutatum, which is in accordance with previous reports (1,2,3,4). The isolate was submitted to the Centraalbureau voor Schimmelcultures in the Netherlands (CBS 131813). The internal transcribed spacer (ITS) region of the fungal DNA was amplified with ITS1F and ITS4 primers, sequenced, and submitted to NCBI GenBank (Accession No. JQ424934). BLASTn searches of GenBank using the ITS sequence revealed 99% similarity with database sequences of C. acutatum. Since the pathogen was found in the main Montenegrin strawberry production area, it poses a threat to strawberry production in Montenegro. To our knowledge, this is the first report of anthracnose fruit rot of strawberry in Montenegro. References: (1) S. G. Bobev et al. Plant Dis. 86:1178, 2002. (2) F. M. Dai et al. Plant Dis. 90:1460, 2006. (3) U. Nilsson et al. Plant Dis. 89:1242, 2005. (4) A. Stensvand et al. Plant Dis. 85:558, 2001.

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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 Fusarium oxysporum Causing Soft Fruit Rot Disease of Gray Jujube (Zizyphus jujuba) in China

Plant Disease ◽

10.1094/pdis-04-13-0379-pdn ◽

2013 ◽

Vol 97 (11) ◽

pp. 1509-1509 ◽

Cited By ~ 1

Author(s):

M. Zhang ◽

Y. Q. Zu ◽

Y. Yang ◽

Y. Wang ◽

D. X. Li ◽

...

Keyword(s):

Apical Cell ◽

Morphological Characteristics ◽

Soft Rot ◽

Fruit Rot ◽

Potential Health ◽

Healthy Tree ◽

First Report ◽

Jujube Fruit ◽

Zizyphus Jujuba ◽

Fusarium Sp

Gray Jujube, Zizyphus jujuba Mill., is a fruit crop unique to China that produces small fruit of high nutritional value with potential health benefits (2). In mid-September 2011, a fruit rot affecting approximately 10% of gray jujube fruit was observed in Xinzheng Date Garden, Henan Province, China. The diseased fruits exhibited small, oval, pale reddish brown lesions that expanded into clear concentric rings. Over time, the superficial lesions developed into soft rot affecting the whole fruit that produced a pungent odor. A putative Fusarium sp. was isolated by a single spore isolations from conidiophores produced on the decaying fruit. The isolated colonies first appeared on potato dextrose agar (PDA) as white to light yellow, then turned light pink. Falciform macroconidia were produced on PDA and were straight to slightly curved, usually 3-septate, short or medium long, 15.0 to 28 × 2.5 to 4.0 μm, with a curved apical cell and foot shaped to pointed basal cell. Microconidia were produced in false heads on Synthetic Nutrient-poor Agar (SNA), and were oval, 0-septate, 5.0 to 9.5 × 1.5 to 2.8 μm. Phialides were cylindrical and ranged from 7.0 to 20.0 × 0.7 to 1.4 μm. Chlamydospores were produced singularly and in pairs (1). Pathogenicity of the putative Fusarium sp. was evaluated by surface-sterilizing fresh gray jujubes on a healthy tree field and inoculating by placing a mycelial plug of the Fusarium sp. culture in contact with the fruit. An equal number of fresh gray jujube fruits were placed in contact with non-colonized PDA plugs to serve as a control. Each jujube fruit was wounded three times to create three holes close together using a steel needle (0.5 mm diameter), before inoculation with an agar plug. All the branches with inoculated fruits were enclosed in a clear plastic bag to maintain humidity and prevent cross contamination. After 3 days, inoculated jujubes exhibited the similar symptoms to those originally observed on the naturally infected fruits. Colonies resembling the Fusarium sp. isolated from the original lesions were obtained from each of the symptomatic fruits. Fruit inoculated with un-colonized PDA plugs remained asymptomatic and no fungus was isolated from these fruit. Koch's postulates were repeated three times with the same results. Based on the morphological characteristics, the Fusarium sp. was identified as F. oxysporum (1). The identity of the isolate was confirmed to be F. oxysporum by DNA sequencing of the elongation factor 1-alpha (EF-1a) gene (GenBank Accession No. KC796007), which was 99% homologous to those of other F. oxysporum isolates (JF430187 and JF430188). To our knowledge, this is the first report of F. oxysporum causing soft rot in fresh gray jujubes in Henan. This disease affects the yield and quality of fresh gray jujubes and potentially may threaten the jujube industry. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual, 2006. (2) J. Sheng et al. Acta Hortic. 620:203, 2003.

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