First Report of Twig Canker of Hazelnut Caused by Fusarium lateritium in Italy

Cultivation of hazelnut (Corylus avellana L.) has considerable economic potential in Italy, in particular, in the northern Lazio Region. Since early summer of 2000, cankered twigs have been observed on hazelnut trees that were severely affected by gray necrosis, which is a disease complex causing fruit drop (1). In subsequent years, sunken areas were observed on 1-year-old shoots from late April through May. The resulting cankers had reddish brown margins and the death of the cambium in the infected area and produced an L-shaped malformation of twigs. Girdling of the twig by the canker resulted in death of the foliage. Yellow-to-orange sporodochia were evident on cankers by early June. Isolations were made from the margins of young cankers from 20 twigs collected from 10 trees. Tissue pieces were plated onto potato dextrose agar (PDA) after surface disinfection with 1% sodium hypochlorite. Slow-growing, cream-to-reddish brown colonies with sparse aerial mycelium emerged from 80% of diseased tissue pieces within 10 days of incubation at 20 to 22°C. Conidial production was induced by keeping pure cultures at 22 to 25°C under natural light but out of direct sunlight. Within 1 month, sporodochia bearing ellipsoidal, spindle-shaped, commonly 1 to 3 septate macroconidia developed. Intercalary chlamydospores were often present in chains. Single conidia were subcultured on carnation leaf agar (CLA). On the basis of morphological and cultural characteristics, the fungus was identified as Fusarium lateritium Nees. (2). Pathogenicity tests were conducted outdoors on the current year's shoots of hazelnut trees with four isolates derived from single conidia of F. lateritium. Inocula used were either mycelial plugs cut from the margin of actively growing cultures or small (10 × 10 mm) pieces of sterile cheesecloth soaked in 1 × 106 conidia per ml suspension. The mycelial plugs were placed under the bark, while the soaked cheesecloth pieces were wrapped around an area that had been wounded by gently scraping off a length of the bark (approximately 10 mm) with a sterile needle. All the inoculations were wrapped with Parafilm to prevent desiccation. Six inoculations per isolate were performed. In a similar manner, controls were inoculated with agar plugs or water only. After 3 months, the length and width of each canker were measured. For both inoculation methods, cankers were similar to those observed in nature and averaged 20.6 × 5 mm, while the controls did not show any symptoms. F. lateritium was consistently reisolated from the canker margins of the inoculated shoots. To our knowledge, this is the first report of F. lateritium causing twig cankers on hazelnut. The fungus has been reported to cause cankers on several tree species, including Malus domestica (apple), Morus spp. (mulberry), Sophora japonica (Japanese pagoda tree), Robinia pseudoacacia (black locust), Citrus spp., and Pyrus pyrifolia (Asian pear). References: (1) A. Belisario et al. Inf. Agrario 59(6):71, 2003. (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University, University Park, 1983.

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First Report of Fusarium lateritium as the Agent of Nut Gray Necrosis on Hazelnut in Italy

Plant Disease ◽

10.1094/pdis-94-4-0484a ◽

2010 ◽

Vol 94 (4) ◽

pp. 484-484 ◽

Cited By ~ 7

Author(s):

A. Santori ◽

S. Vitale ◽

L. Luongo ◽

A. Belisario

Keyword(s):

Fusarium Species ◽

Central Italy ◽

Early Summer ◽

State University ◽

In Planta ◽

Laboratory Manual ◽

First Report ◽

Fusarium Lateritium ◽

Potential Pathogen ◽

Suspension Drops

Hazelnut (Corylus avellana) is a traditionally cultivated nut species in Italy. Italy is the second largest producer of hazelnut in the world after Turkey. In early summer of 2000, a severe fruit drop (up to 60%) was observed in several hazelnut orchards located in the Latium Region in central Italy. The severity of yield losses led to investigating the etiology of the disease subsequently named nut gray necrosis (NGN) based on symptoms observed on the affected fruit. Symptoms consisted of a brown grayish necrotic spot/patch on the nut shell and bracts, sometimes involving the petiole (1). Isolations of the potential pathogen were from tissue that was sampled starting from bloom of female flowers to fully ripened fruit. Isolations from symptomatic tissue consisted of placing onto potato dextrose agar (PDA) small tissue fragments (approximately 3 mm) cut from the margin of lesions, while asymptomatic material (entire flowers or young fruit) was sectioned into small pieces. All the material was previously surface disinfected with 1% NaOCl. Slow-growing, dark grayish olive colonies were obtained consistently within 14 days of incubation at 20 to 22°C from symptomatic and asymptomatic material. Sporodochia were rarely produced on PDA, but never on carnation leaf agar. Dark grayish olive colonies were assigned to a Fusarium sp. Detached hazelnut fruit exposed to 20 μl of a mycelial suspension (105 CFU/ml) and incubated in a moist chamber at room temperature for 10 days produced orange sporodochia bearing 3 to 5 septate macroconidia (35 × 4 μm). On the basis of morphology, the fungus was identified as Fusarium lateritium Nees. (3,4). The identity was confirmed by internal transcribed spacer rDNA sequence comparison with BBA65248 (GenBank Accession No. AF310980). The sequences of two isolates, ISPaVe1874 and ISPaVe1976, were deposited in GenBank (Accession Nos. FN547420 and FN547445, respectively). Pathogenicity tests were performed in planta by inoculating, with the aforementioned isolates, young to fully formed fruit (approximately 24 mm in diameter) either with a drop of mycelial (106 CFU/ml) or conidial (106 conidia/ml) suspension. Drops were placed between the nut and leafy involucre. Controls were treated with sterile water only. Within 2 weeks after inoculation, a grayish necrosis developed on all the inoculated fruit and was similar to symptoms originally observed in the field. No differences were observed between the two methods of inoculation. On full-sized fruit, lesions extended from the shell to inner tissues. The pathogen was consistently reisolated from lesions. Controls showed no symptoms. To our knowledge, this is the first report of F. lateritium as the causal agent of nut gray necrosis on hazelnut in Italy, and this pathogen has never been reported as an agent of necrosis and drop of hazelnut fruit, but it was previously reported as an agent of twig cankers (2). References: (1) A. Belisario et al. Inf. Agrario 59:71, 2003. (2) A. Belisario et al. Plant Dis. 89:106, 2005. (3) J. F. Leslie et al. The Fusarium Laboratory Manual. Blackwell Publishing Press Ltd, Oxford, UK, 2006. (4) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, 1983.

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First Report of Root and Stem Rot Caused by Phytophthora nicotianae on Peperomia tetraphylla in China

Plant Disease ◽

10.1094/pdis-94-9-1171c ◽

2010 ◽

Vol 94 (9) ◽

pp. 1171-1171 ◽

Cited By ~ 1

Author(s):

D. X. Zeng ◽

X. L. Wu ◽

Y. H. Li

Keyword(s):

Southern China ◽

Aerial Mycelium ◽

Its Region ◽

Soil Extract ◽

Phytophthora Nicotianae ◽

Stem Rot ◽

Molecular Characteristics ◽

Its Sequence ◽

First Report ◽

Pure Cultures

Peperomia tetraphylla, an evergreen herb, is becoming increasingly popular as a potted ornamental plant in southern China. In the summer of 2008, in some commercial flower nurseries in Shenzhen, Guangdong Province, P. tetraphylla showed extensive black stem and root rot, with leaves dropping from the rotten stem. Small pieces (approximately 3 mm2) of stems and leaves were excised from the margins of the black lesions, surface disinfected for 30 s to 1 min in 0.1% HgCl2, plated onto potato dextrose agar (PDA), and incubated at 25°C in the dark. All the plated samples yielded Phytophthora, and microscopic examination of pure cultures grown on PDA plates showed arachnoid colonies with abundant aerial mycelium, chlamydospores, and a few sporangia. Numerous sporangia were formed in sterile soil extract. Sporangia were ovoid or obpyriform, noncaducous, with prominent solitary papillae, and measured 31 to 52 μm (average 38 μm) × 21 to 34 μm (average 27 μm). Chlamydospores were spherical and 21 to 34 μm in diameter (average 28 μm). The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using primers ITS4/ITS5 and sequenced (2). The ITS sequence, when submitted for a BLAST search in the NCBI database, showed 100% homology with the sequences of two reference isolates of Phytophthora nicotianae (Accession Nos. AY833526 and EU433396) and the consensus ITS sequence was deposited in the NCBI as Accession No. GQ499373. The isolate was identified as Phytophthora nicotianae on the basis of morphological and molecular characteristics (1). Pathogenicity of the isolate was confirmed by inoculating 1-year-old plants of P. tetraphylla growing in pots. The isolate was grown for 7 days on PDA plates and mycelial plugs, 5 mm in diameter and taken from the advancing margins of the colonies, were buried approximately 1 cm deep near the base of the stem in such a way that the mycelium on the plugs was in contact with the surface of the stem, which had been wiped earlier with 70% ethanol and gently wounded with a needle. Plants treated the same way but inoculated with sterile PDA plugs served as control plants. Three plants in each pot were inoculated and there were five replications each for the treatment and the control. All plants were kept in a greenhouse at 22 to 32°C. After 6 to 7 days, the inoculated plants showed black lesions around the mycelial plugs; symptoms of root and stem rot developed rapidly thereafter and the plants collapsed within 2 weeks. All symptoms on the inoculated plants were identical to those observed in naturally diseased plants, whereas the control plants remained healthy. The same fungus was consistently reisolated from the inoculated plants. To our knowledge, this is the first report of Phytophthora nicotianae on P. tetraphylla in China. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (2) J. B. Ristaino et al. Appl. Environ. Microbiol. 64:948, 1998.

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First Report of Stem Dieback Caused by Lasiodiplodia parva on Styphnolobium japonicum in China

Plant Disease ◽

10.1094/pdis-08-21-1598-pdn ◽

2021 ◽

Author(s):

Ziwei Zhou ◽

Cuiping Wu ◽

Jing Yang ◽

Jieying Xu ◽

Zhenpeng Chen ◽

...

Keyword(s):

Robinia Pseudoacacia ◽

Elongation Factor ◽

Aerial Mycelium ◽

Random Trees ◽

Molecular Evidence ◽

Conidial Suspension ◽

Internal Transcribed Spacer Region ◽

Accurate Identification ◽

Individual Tree ◽

First Report

Styphnolobium japonicum (L.) Schott is a variant of Robinia pseudoacacia and is a popular Asian tree widely used in traditional medicine. From March 2019 to 2021, a disease was found on the campus of Nanjing Forestry University and several landscape sites of Xuanwuhu Park, causing dieback. Most of the trees (approximately 40%) have rotted branches. On average, 60% of the branches per individual tree were affected by this disease. The initial round lesions were grayish brown. In the later stage, the whole branch becomes black and produces spherical fruiting bodies . Twenty diseased branches were picked from three random trees. Small tissues (3-4mm²) were surface-sterilized in 75% ethanol for 30 s followed by 1% NaClO for 90 s and placed on potato dextrose agar (PDA), and incubated in the dark at 25°C for three days. Hyphae were visibly emerged from 70% of the samples. Three representative isolates (Lth-soj1, Lth-soj2, and Lth-soj3) were obtained and deposited in China’s Forestry Culture Collection Center (Lth-soj1: cfcc55896, Lth-soj2: cfcc55897, Lth-soj3: cfcc55898). The colonies of three isolates on PDA were fast growing and white, which turned grey to dark grey after 3 days of incubation in the dark at 28°C . Two-weeks old colonies were black and fluffy on PDA, with abundant aerial mycelium, and the reverse side too was black in color. The fungus usually grew well on PDA and produced pycnidia and conidia within 3–4 weeks. Conidia were initially hyaline and aseptate, ellipsoid to ovoid, with granular content, apex broadly rounded, remaining hyaline and later becoming dark brown, one septate, thick walled, base truncate or round and longitudinally striate. The conidia (n=30) of a representative isolate（Lth-soj1）, measured 24.3 ± 0.3 μm in length and 13.3 ± 0.5 μm in width . The morphological characters of the three isolates matched those of Lasiodiplodia parva(Alves et al. 2008). For accurate identification, the DNA of the three isolates was extracted. The internal transcribed spacer region (ITS), translation elongation factor (EF1-α), and β-tubulin 2 (TUB2) genes were amplified using the primer pairs ITS1/ITS4 , EF1-728F/EF1-986R, and Bt2a/Bt2b , respectively. The sequences were deposited in GenBank under accession numbers MZ613154, MZ643245 and MZ643242 for Lth-soj1, MZ613155, MZ643246 and MZ643244 for Lth-soj2, and MZ613157, MZ643247 and MZ643243 for Lth-soj3. The ITS, EF1-α, and TUB2 sequences of isolate Lth-soj1 (GenBank Acc. No. MZ613154, MZ643245, MZ643242) were 100% (519/519 nt), 99.34% (299/301 nt), and 99.77% (436/437 nt) identical to those of MZ182360, EF622063, and MK294119, respectively. Interspecific differences were observed in a maximum-likelihood tree of Lasiodiplodia species using the concatenated dataset. Based on the morphological and molecular evidence, the isolates were identified as L. parva. The pathogenicity of three isolates were tested on potted three-year-old seedlings (100-cm tall) of S. japonicum maintained in a greenhouse. Healthy stems were wounded with a sterile needle then inoculated with 10 µL of conidial suspension. Control plants were treated with ddH2O. In total, 12 seedlings were inoculated including three controls. Three seedlings per isolate and 10 stems per seedling were used for each treatment. The plants were kept inside sealed polythene bags for the first 24 h and sterilized H2O was sprayed into the bags twice a day to maintain humidity and kept in a greenhouse at the day/night temperatures at 25/16°C. Within seven days, all the inoculated points showed lesions similar to those observed in field and the conidiomatas growing on the surface of the branches, whereas controls were asymptomatic . The infection rate of each of the three isolates was 100%. The strain was re-isolated from the lesions and sequenced as L.parva, whereas not from control stems. This is the first report of L. parva causing rotten branches of S. japonicum in China and the worldwide. These data will help to develop effective strategies for managing this newly emerging disease.

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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 Branch Blight of Tree Peony Caused by Phoma glomerata in China

Plant Disease ◽

10.1094/pdis-12-12-1129-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1114-1114 ◽

Cited By ~ 4

Author(s):

D. Zhao ◽

Y. B. Kang

Keyword(s):

Disease Incidence ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Its2 Region ◽

Tree Peony ◽

Disease Symptoms ◽

First Report ◽

Plastic Bag ◽

Pure Cultures ◽

Branch Dieback

Tree peony (Paeonia suffruticosa Andrews) is a perennial woody deciduous shrub native to China and famous for its beautiful flowers. Starting in early autumn 2010, blighted branches of tree peony were detected in the International Peony Garden in Luoyang. The disease incidence was greater than 10% and disease symptoms included bulb atrophy and twig and branch dieback. Pycnidia were embedded within the bark of diseased branches. They were small, black, ostiolate, and measured 145 to 275 × 140 to 251 μm. Pycnoconidia were single-celled, hyaline or sandy beige, rounded to ellipsoidal, and 3.9 to 10.3 × 2.3 to 7.0 μm. Pure cultures were obtained by plating the pycnoconidia on potato dextrose agar (PDA). In culture, the fungus produced a circular, white to pink colony with pyknotic and linter shaped aerial mycelium. Numerous pycnidia, initially brown and dark at maturity, were embedded in the mycelium, especially in the center of the colony, with a few of them scattered in the edge. The morphological characteristics were consistent with Phoma (2). The ITS1-5.8S-ITS2 region of three isolates were PCR amplified and sequenced with primers ITS1 and ITS4. Sequences (GenBank Accession No. JX885584) showed 99% identity with reference isolates of Peyronellaea glomerata (Corda) Goid (AB470906.1 and HQ380779.1) and Phoma glomerata (Corda) Wollenw. & Hochapfel (EU098115.1). These two species are synonyms (1). To test pathogenicity, nine healthy branches of 3-year-old potted tree peony plants were wound-inoculated with a PDA disk containing pycnidia from an actively growing colony of P. glomerata. Three control branches were inoculated with sterile PDA disks. Each inoculated branch was wrapped in a plastic bag and maintained in a greenhouse at 25 to 28°C. After 3 days, brown patches appeared on inoculated branches and extended by up to 1 cm. Pycnidia identical to those observed in the field and in storage appeared on all inoculated branches 7 days after inoculation. Control branches did not show symptoms. The pathogen was reisolated from inoculated branches, fulfilling Koch's postulates. P. glomerata was reported as the causal agent of withering of flowers and young shoots of grapevines in Yugoslavia (3). To our knowledge, P. glomerata and Botryosphaeria dothidea have always been reported together, causing branch wilting or dieback. To our knowledge, this is the first report of branch blight of tree peony caused by P. glomerata in China. References: (1) M. M. Aveskamp et al. Mycol. Soc. Am. 101:363, 2009. (2) G. H. Boerema et al. Studies in Mycology, 3, 1973. (3) A. Šaric-Sabadoš et al. Atti Ist. bot. Univ. Pavia 18:101, 1960.

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First report of Colletotrichum fructicola causing anthracnose on water hyacinth in China

Plant Disease ◽

10.1094/pdis-12-20-2621-pdn ◽

2021 ◽

Author(s):

Weifeng Huang ◽

Zhenyue Lin ◽

Zhi Zhang ◽

Jianming Chen

Keyword(s):

Water Hyacinth ◽

Plant Pathogens ◽

Phylogenetic Analyses ◽

Leaf Tissue ◽

Aerial Mycelium ◽

Aquatic Weed ◽

Promising Alternative ◽

First Report ◽

Modified Dna ◽

Pure Cultures

Water hyacinth (Eichhornia crassipes), a worst invasive aquatic weed has been caused the widespread problems for the water bodies and water resources, particularly the case in China. Plant pathogens are a promising alternative as biocontrol agents (Dagno et al. 2011), but success in this strategy will require the selection of some highly virulent pathogen strains. In September 2020, irregular necrotic lesions on leaves, stems, as well as crown and petiole rots symptoms, occurred on water hyacinth, in Minjiang and Xiyuanjiang watershed, in Fuzhou, China. Fragments from symptomatic leaf tissue (5x5mm) were superficially disinfected in 0.1% MgCl2 solution for 30 s, followed by rinsing three times in sterile water, placed on potato dextrose agar (PDA), and then incubated in darkness at 28°C for 5 days. Two fungal isolates (F3 and F11) were recovered and obtained pure cultures from the affected leaves and deposited in the Institute of Oceanography, Minjiang University. The colonies were stale, with felted, dense, pale grey aerial mycelium, scattered dark based acervuli with orange conidial masses near centre; in reverse side pinkish orange with patches of grey pigment near centre. The hyphae were septate, branched, and 2 to 6 µm in width. Appressoria were not observed. Conidiogenous cells were 20–24 × 3.5–4.5 µm, cylindric to flask-shaped, towards margin the conidiophores with a much looser structure, conidiogenous loci at apex and often also at septa. Asci were 60-80 × 15-20 µm, cylindric to subfusoid, 8–spored. Ascospores were 17-23 × 4-6 µm, gently curved, tapering to quite narrow, rounded ends. Perithecia mature after about 15 days, and were dark brown, subglobose, and 50-150 μm in diameter, and with scattered, dark brown setae about 50–80 µm long. Conidia were 15-25 × 4.5-6 μm, unicellular, colorless, and cylindrical to fusiform. Genomic DNA from two isolates was extracted with a modified DNA Midi Kit (TIANGEN, Inc., Beijing, China), and amplified using ITS4/ITS1F, CL1/CL2A, CHS-79F/CHS-345R, T1/T2 and GDF/GDR primers by PCR (Weir et al. 2012; White et al. 1990). Sequences of F3 and F11 were submitted to GenBank (accession no. ITS, MW307302, MW307303; CAL, MW303427, MW303429; CHS-1, MW303428, MW303430; TUB, MW531006, MW531007; GADPH, MW531008, MW531009). A phylogenetic tree using the maximum likelihood methods and including ITS-CHS-CAL-TUB-GADPH concatenated sequences from Colletotrichum gloeosporioides complex was obtained (Cai et al. 2009; Damm et al. 2018; Weir et al. 2012). Phylogenetic analyses revealed that isolate F3 and F11 were grouped into the clade C. fructicola. To test Koch’s postulates, conidial suspensions (107 CFU/ml) of the isolate F3 and F11 were micro-injected into 20 water hyacinth seedlings per isolate. Another 20 seedlings were injected with water without conidia as control. Inoculated plants were kept in 50-liter plastic tanks, and maintained in a greenhouse at room temperature (19-24ºC) for two weeks. The Koch’s test was conducted twice. After 10 days, typical anthracnose symptoms similar to the field appeared on the inoculated leaves, while the control leaves remained asymptomatic. The C. fructicola was re-isolated and identified by microscopy, PCR and sequencing, but not on non-inoculated controls. Anthracnose disease caused by C. fructicola has been reported affecting numerous plants worldwide, including cotton, coffea, grape, citrus, ect (Guarnaccia et al. 2017). However, to our knowledge, this is the first report of C. fructicola causing anthracnose on water hyacinth in China. Further studies for the efficacy of C. fructicola and/or of the genus Colletotrichum as biocontrol agent for water hyacinth or another aquatic plant are required (Ding et al. 2007; Dagno et al. 2012).

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First Report of Mango Malformation Disease Caused by Fusarium mangiferae in Sri Lanka

Plant Disease ◽

10.1094/pdis-09-12-0877-pdn ◽

2013 ◽

Vol 97 (3) ◽

pp. 427-427 ◽

Cited By ~ 6

Author(s):

G. D. Sinniah ◽

N. K. B. Adikaram ◽

I. S. K. Vithanage ◽

C. L. Abayasekara ◽

M. Maymon ◽

...

Keyword(s):

Sri Lanka ◽

Fusarium Species ◽

Aerial Mycelium ◽

Pcr Primers ◽

Economic Losses ◽

Fusarium Spp ◽

First Report ◽

Specific Pcr ◽

Species Specific ◽

Mango Malformation

Mango malformation disease (MMD) is one of the most devastating diseases causing severe economic losses to this crop worldwide. MMD has not been reported in Sri Lanka although the disease was reported in neighboring India over a century ago. Abnormal, thick, and fleshy mango panicles (40%) and proliferating stunted shoots (<1%) showing characteristic malformation symptoms were observed in Peradeniya-Kandy area (7°17'4.15” N, 80°38′14.08” E). Malformed inflorescences and vegetative shoots were collected during January to March and September to November, in 2008 through 2012. Pieces of malformed tissues were surface sterilized in 1% sodium hypochlorite and transferred to potato dextrose agar (PDA). The plates were incubated at 26 ± 2°C for 7 days. Monoconidial cultures of 41 isolates that resembled Fusarium spp. were obtained. Colonies showed white sparse aerial mycelium and magenta-dark purple pigmentation on the underside. Growth rate of the isolates averaged 3.67 mm/day in the dark at 25°C on PDA. To stimulate conidia development, Fusarium isolates were transferred to carnation leaf agar (CLA). Sympodially branched conidiophores bearing mono- and polyphialides with 2 to 3 conidiogenus openings originated erect and prostrate on aerial mycelium. Oval to allontoid, abundant microconidia were produced in false heads on mono- and polyphialides. Dimensions of aseptate conidia were 2.5 to 12.5 (6.47) × 1.25 to 3.8 (2.29) μm. Macroconidia were long and slender, 3 to 5 celled and 27.5 to 47.5 (38.59) × 2.5 to 5 (2.94) μm. Chlamydospores were absent. These characters are consistent for F. mangiferae. DNA was extracted from 30 monoconidial Fusarium isolates (1) and amplified with species-specific PCR primers 1-3F/R (forward: 5′-TGCAGATAATGAGGGTCTGC-3′; reverse: 5′-GGAACATTGGGCAAAACTAC-3′) (3). Eight isolates from malformed inflorescences (I6, I13, I15, and I16) and malformed vegetative tissues (V1, V2, V3, and V4), were identified as F. mangiferae based on a 608-bp species-specific amplified DNA fragment. Pathogenicity of F. mangiferae isolates, I15 and V2, was tested on 1-year-old seedlings cv. Willard planted in 10-liter plastic pots. Conidia suspensions (107 conidia/ml of 0.1% water agar) were obtained from 10-day-old monoconidial cultures. Each isolate was inoculated onto 15 apical buds by placing drops (20 μl) of conidia (2). Both F. mangiferae isolates, I15 and V2, on artificial inoculation produced typical floral malformation symptoms in 40% of the buds, up to 10 weeks after inoculation. The Fusarium isolates recovered were identical in colony and mycelia morphology and conidia dimensions to the original F. mangiferae isolates. No Fusarium species were recovered from control flower buds. To our knowledge, this is the first report of MMD in the inflorescence and the vegetative shoots caused by F. mangiferae in Sri Lanka. Isolation of other Fusarium spp. that were not identified as F. mangiferae in this study suggests that additional Fusarium spp. may be associated with the MMD in Sri Lanka. Further studies are needed to confirm the identity of these Fusarium isolates, their role in MMD, and the distribution over the island. Since the disease is likely to drastically reduce productivity, measures will be required to protect 12,160 ha of mango cultivation from this devastating disease. References: (1) S. Freeman et al. Exp. Mycol. 17:309, 1993. (2) S. Freeman et al. Phytopathology 89:456, 1999. (3) Q. I. Zheng and R. C. Ploetz. Plant Pathol. 51:208, 2002.

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First Report of Gladiolus Corm Rot Caused by Fusarium proliferatum in Oman

Plant Disease ◽

10.1094/pdis-03-12-0233-pdn ◽

2013 ◽

Vol 97 (2) ◽

pp. 284-284 ◽

Cited By ~ 1

Author(s):

I. H. Al Mahmooli ◽

F. Al Balushi ◽

O. Doyle ◽

A. M. Al Sadi ◽

M. L. Deadman

Keyword(s):

Fusarium Species ◽

Elongation Factor ◽

Aerial Mycelium ◽

Fusarium Proliferatum ◽

State University ◽

Translation Elongation ◽

First Report ◽

Factor Alpha ◽

Artificial Inoculations

Hybrid gladiolus varieties have potential as a major ornamental crop in Oman. Grown for the cut-flower industry, their production has increased significantly in recent years. In 2010, during a field trial of two hybrid varieties (Red Majesty and Mascagni) grown in sandy soil at Al Moballah, Muscat, approximately 3% of Red Majesty plants and 12% of Mascagni plants showed signs of wilting and yellowing prior to plant death. In all cases, tissue taken from 20 diseased corms yielded Fusarium-like colonies on potato dextrose agar (PDA). Colonies were light to dark purple in color with dense and abundant aerial mycelium; macroconidia were 33.8 × 4.8 μm with 3 to 5 septa per spore; microconidia were 13.5 × 4.8 μm with 0 to 1 septa per spore and were in chains (mean of 50 spores in both cases). No chlamydospores were observed. In vitro characters and spore measurements conformed to previously described features of Fusarium proliferatum (Matsushima) Nirenberg (2). Mycelial plugs (5 mm in diameter) were taken from 5-day-old cultures of F. proliferatum grown on 2.5% PDA and wrapped on the base of Gladiolus corms using Parafilm and wet cotton. The Parafilm was removed after 7 days of inoculation. The corms were kept in moistened polythene bags for and symptoms were recorded. Control corms were inoculated using PDA (1). Artificial inoculations resulted in rot symptoms on all corms within 14 days and fungal colonies identical to initial isolations were recovered from artificially infected corms. Rotting was not observed in corms inoculated using PDA alone. Identification of F. proliferatum was confirmed using sequences of the internal transcribed spacer (ITS) of the ribosomal DNA (ITS1 and ITS4 primers) and sequences of the translation elongation factor alpha (TEF-1) gene (EF-1-986 and EF-728 primers). The ITS and TEF-1 sequences were found to share 99.8% and 99.6% nucleotide similarity to previously published sequences of the ITS (HQ113948) and EF (JN092351) regions of F. proliferatum in GenBank, respectively. The ITS sequence of one isolate was assigned GenBank Accession No. JN86006. To our knowledge, this is the first report of the occurrence of F. proliferatum in Oman or in the Arabian Peninsula. References: (1) C. Linfield. Ann. Appl. Biol. 121:175, 1983. (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, USA, 1983.

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First Report of Fusarium denticulatum from Sweet Potato in Venezuela

Plant Disease ◽

10.1094/pdis.2003.87.2.202a ◽

2003 ◽

Vol 87 (2) ◽

pp. 202-202

Author(s):

M. S. González ◽

F. Fuenmayor ◽

F. Godoy ◽

R. Navas

Keyword(s):

Sweet Potato ◽

Ipomoea Batatas ◽

Germ Plasm ◽

Apical Cell ◽

Aerial Mycelium ◽

Conidial Suspension ◽

First Report ◽

Young Leaves ◽

Pure Cultures ◽

Leaf Distortion

During 2001and 2002, 53 accessions of sweet potato (Ipomoea batatas L.) from a germ plasm collection maintained in the field at Centro Nacional de Investigaciones Agropecuarias, Maracay, Venezuela, were evaluated for diseases. Sweet potato accessions Catemaco and 2878 were symptomatic for chlorotic leaf distortion with deformation of young leaves and stunted vines. Symptomatic nodes and shoot tips were excised, surface disinfested in 0.5% sodium hypochlorite, cultured on potato dextrose agar (PDA), and incubated at 28°C. Pale pink colonies with white aerial mycelium developed from symptomatic tissues. At 20°C, pure cultures on PDA developed slow-growing, aerial, white-to-pink mycelium. Pigmentation in reverse was light orange. Conidia aggregated in false heads, and orange sporodochia were abundant. Conidiophores in aerial mycelium were prostrate, short, and sometimes branched. Sporodochial conidiophores were branched. Phialides were mostly monophialidic but occasionally polyphialidic and averaged 25.0 × 3.0 µm. Microconidia were abundant, long, oval to allantoid, and 0 to 1 septate. Macroconidia were fusiform to falcate with a beaked apical cell and a footlike basal cell, 3 to 5 sepate, and 38 to 45 × 3.6 to 4.0 µm. Chlamydospores were absent. The fungus was identified as Fusarium denticulatum Nirenberg and O'Donnell (1). Ten 25-cm-long vine-tip cuttings of accessions Catemaco and 2878 were immersed in a conidial suspension (1 × 106 conidia per ml) of F. denticulatum. As a control, vines were immersed in sterile, distilled water. After inoculation, each cutting was planted in a 13-cm plastic pot containing a soil/sand (1:1) mixture. Inoculated plants were covered with plastic bags for 48 h and grown in a greenhouse at temperatures ranging from 30 to 38°C. After 3 months, three inoculated plants of accession Catemaco and two plants of accession 2878 developed purple terminals and moderate interveinal chlorosis. Leaf distortion was not observed. F. denticulatum was recovered from both symptomatic and asymptomatic inoculated plants. To our knowledge, this is the first report of F. denticulatum from sweet potato germ plasm in Venezuela. Dried, pure cultures and slides of the fungus are being deposited in the Albert S. Muller Herbario Micologico (VIA). Reference: (1) H. I. Nirenberg and K. O'Donnell. Mycologia 90:434, 1998.

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First Report of Rhizoctonia Blight of a Coastal Redwood Tissue-Culture-Derived Saplings Caused by Rhizoctonia solani AG-IV in Taiwan

Plant Disease ◽

10.1094/pdis-92-4-0655a ◽

2008 ◽

Vol 92 (4) ◽

pp. 655-655

Author(s):

W. W. Hsiao ◽

Y. S. Wu ◽

Y. N. Wang ◽

B. L. Huang ◽

L. C. Huang

Keyword(s):

Tissue Culture ◽

Rhizoctonia Solani ◽

Aerial Mycelium ◽

Soil Surface ◽

Plant Diseases ◽

First Report ◽

Tall Tree ◽

Pure Cultures ◽

The Republic ◽

Central Taiwan

Coastal redwood (Sequoia sempervirens (D. Don) Endl.) is native to North America. This tall tree species is used for forestation and lumber; its wood is also used for furniture, its burls for art ware, and its bark for fuel, insulation, and mulch. In August 2005, an instance of wilt was observed among 2-year-old tissue-culture-cloned plants (2) in the Sitou Forest of central Taiwan. Essentially, all plants were infected. The leaves or stems near the ground were affected first, but the wilt soon spread over the entire plant with the leaves becoming grayish brown and water soaked, and then wilting, drying, and finally defoliation occurred. Aerial hyphae were present over the affected areas, aerial mycelium was cob-web-like, hyaline, later becoming slightly brown. Hyphae were 6.5 to 10.4 μm wide with right-angle branching and septal constriction at their bases. Sclerotia were hemispherical, subglobose, to irregular in shape, 1 to 2 mm, and brown. The perfect stage of the fungus was not found. The fungus was identified as Rhizoctonia solani Kühn (3). Vegetative cells were stained with alkaline safranin solution and identified as multinucleate (1). Portions of the stem that displayed symptoms, together with adjacent healthy tissue, were disinfested for 1 min in 0.5% NaOCl and plated on to potato-dextrose agar (PDA) (Merck, Darmstadt, Germany) supplemented with 100 mg/L of ampicillin (Sigma, St. Louis, MO). Single hyphal tips were transferred to PDA and two isolates were established as pure cultures. On the basis of hyphal anastomosis with AG-IV tester isolates (exfop234, exfop241, and exfop250) (1), the fungus was identifed as R. solani AG-IV. Pathogenicity of the fungal isolates was confirmed by inoculating 2-month-old tissue-culture-derived S. sempervirens plants that were grown in pots and incubated in a growth chamber maintained at 28°C with a relative humidity above 95%. Inoculum consisted of a single mycelial 5-day-old 0.5-cm disc grown on PDA of the pathogen placed on the soil surface touching the base of each plant. Four plants were inoculated with mycelium and the four control plants were noninoculated. Inoculated plants wilted gradually over 4 days and all plants developed severe stem rot and were dead in 6 days, whereas control plants remained symptomless. The Rhizoctonia solani AG-IV was reisolated from all inoculated plants. This fungus has been observed to cause disease in many species of plants (4), but to our knowledge, this is the first report of Rhizoctonia blight of coastal redwood tissue-culture-derived saplings caused by Rhizoctonia solani AG-IV in Taiwan. References: (1) T. T. Chang. Taiwan J. For. Sci. 12:47, 1997. (2) L. C. Huang et al. Plant Physiol. 98:166, 1992. (3) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society, St. Paul, MN, 1991. (4) S. T. Su et al. List of Plant Diseases in Taiwan. The Phytopathological Society of the Republic of China, 2002.

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