scholarly journals First Report of Stem Canker of English Walnut Caused by Fusarium solani in South Africa

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 592-592 ◽  
Author(s):  
W. Chen ◽  
W. J. Swart
Keyword(s):  
South Africa ◽  
Fusarium Solani ◽  
Juglans Regia ◽  
Stem Canker ◽  
The United States ◽  
First Report ◽  
Surface Sterilization ◽  
Similar Disease ◽  
English Walnut ◽  
Artificial Inoculations

Cultivation of English walnut (Juglans regia L.) has considerable economic potential in South Africa. In February 1999, die-back of walnut trees was observed on ≈30% of trees in an orchard in Gauteng Province, South Africa. Die-back was associated with characteristic cankers and discoloration of the cambial tissue of twigs and young branches. Fifty pieces of discolored tissue from the margins of cankers of five trees were transferred to potato dextrose agar (PDA) after surface-sterilization with 0.5% NaOCl. Fungal colonies emerged from all 50 pieces of diseased tissue. Fungi recovered included Fusarium solani (74.5%), Alternaria tenuissima (17.3%), and a Phoma sp. (6.2%). Small pieces of sterile cheesecloth (10 × 5 mm) were cultured on PDA with an isolate of F. solani from infected walnut trees. Colonized pieces of cheesecloth were applied to stems (≈5-mm diameter) of nine potted J. regia plants in a glasshouse. Each stem was wounded by lightly scraping off a length of bark (5 × 5 mm). Colonized cheesecloth was wrapped around the wound and covered with Parafilm to prevent desiccation of mycelia in the cheesecloth. Nine walnut stems were similarly treated with sterile cheesecloth pieces to serve as control treatments. After 4 weeks, die-back of foliage was observed in all plants artificially inoculated with F. solani. Cheesecloth pieces and surrounding bark were removed, and the length and width of each cambial lesion was measured. The mean area of cambial lesions (length by width) resulting from artificial inoculations was 27.3 × 8.5 mm. None of the control plants developed any symptoms. Koch's postulates were confirmed by consistently reisolating F. solani from inoculated plants. A similar disease of black walnut (J. nigra) was reported by Carlson et al. (1) from five central states in the United States. Our findings represent the first report of F. solani as a causal agent of stem canker of English walnut in South Africa. Reference: (1) J. C. Carlson et al. N. J. Appl. For. 10:1, 1993.

scholarly journals First Report of Phytophthora nicotianae and P. citricola Associated with English Walnut Decline in Europe

Plant Disease ◽  
2003 ◽  
Vol 87 (3) ◽  
pp. 315-315 ◽  
Author(s):  
A. Belisario ◽  
M. Maccaroni ◽  
A. M. Vettraino ◽  
A. Vannini
Keyword(s):  
Lateral Roots ◽  
Juglans Regia ◽  
The United States ◽  
Phytophthora Nicotianae ◽  
Malt Extract ◽  
Veneto Region ◽  
Internal Transcribed Spacer Region ◽  
Campania Region ◽  
First Report ◽  
English Walnut

English (Persian) walnut (Juglans regia), among the most widely cultivated species of Juglans worldwide, is cultivated primarily for fruit production but also for timber. In the last 10 years, walnut decline causing leaf yellowing, sparse foliage, overall decline, and plant death has increased in Italian commercial orchards. In Italy, Phytophthora cactorum, P. cambivora, P. cinnamomi, and P. cryptogea are associated with this disease (1,4). Over the last 5 years, P. cinnamomi was the most widely isolated and destructive species (1). Recently, a different species of Phytophthora was isolated from diseased roots and soil from around lateral roots of 10 declining trees in two orchards in the Veneto Region of northern Italy. Another species of Phytophthora was isolated consistently from rotted roots of declining walnut trees in two orchards in the Campania Region of southern Italy. Phytophthora spp. were isolated directly from plant material or Rhododendron spp. leaf baiting on soil samples with PARBhy selective medium (10 mg of pimaricin, 250 mg of ampicillin [sodium salt], 10 mg of rifampicin, 50 mg of hymexazol, 15 mg of benomyl, 15 g of malt extract, 20 g of agar in 1,000 ml of H2O). Two species of Phytophthora were identified based on morphological and cultural characteristics (2). The species from trees in the Veneto Region was identified as P. nicotianae. All isolates produced papillate, spherical to obturbinate, occasionally caducous sporangia with short pedicels, terminal and intercalary chlamydospores, and were mating type A2. The species isolated from trees in the Campania Region was identified as P.citricola. Isolates were homothallic, produced semipapillate, persistent, obclavate to obpyriform sporangia, occasionally with two apices, and antheridia paragynous. Identifications were confirmed by comparing restriction fragment length polymorphism patterns of the internal transcribed spacer region of rDNA with those obtained from previously identified species of Phytophthora. Pathogenicity of two isolates each of P. citricola and P. nicotianae was tested on 2-year-old potted walnut seedlings. Inocula were prepared by inoculating sterilized millet seeds moistened with V8 broth with plugs of mycelium and incubated for 4 weeks at 20°C in the dark. Infested seeds were added to potting soil at a rate of 3% (wt/vol). One day later, pots were flooded for 48 h to promote sporulation. Ten noninoculated seedlings were used as the control. Symptoms were assessed 2 months after inoculation. Seedlings inoculated with P. nicotianae developed necrosis of feeder and lateral roots, but only limited infection of taproots. Seedlings inoculated with P. citricola developed necroses at the insertion points of lateral roots. All four isolates produced visible damage to lateral roots on inoculated plants. P. nicotianae and P. citricola were reisolated from respectively infected roots. Results from these inoculations confirmed P. nicotianae and P. citricola as root pathogens of English walnut. Both species were associated with walnut decline as reported in the United States (3). To our knowledge, this is the first report of P. nicotianae and P. citricola on J. regia in Europe. References: (1) A. Belisario et al. Petria 11:149. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (3) M. E. Matheron and S. M. Mircetich. Phytopathology 75:977, 1985. (4) A. M. Vettraino et al. Plant Dis. 86:328, 2002.

scholarly journals First Report of Fusarium solani Causing Stem Canker in English Walnut in Spain

Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3281-3281
Author(s):  
Antonio Mulero-Aparicio ◽  
Carlos Agustí-Brisach ◽  
María del Carmen Raya ◽  
María Lovera ◽  
Octavio Arquero ◽  
...  
Keyword(s):  
Fusarium Solani ◽  
Stem Canker ◽  
First Report ◽  
English Walnut

scholarly journals First Report of Stem Canker of Salsola tragus Caused by Diaporthe eres in Russia

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 110-110 ◽  
Author(s):  
T. Kolomiets ◽  
Z. Mukhina ◽  
T. Matveeva ◽  
D. Bogomaz ◽  
D. K. Berner ◽  
...  
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Stem Canker ◽  
The United States ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Stem Lesions

Salsola tragus L. (Russian thistle) is a problematic invasive weed in the western United States and a target of biological control efforts. In September of 2007, dying S. tragus plants were found along the Azov Sea at Chushka, Russia. Dying plants had irregular, necrotic, canker-like lesions near the base of the stems and most stems showed girdling and cracking. Stem lesions were dark brown and contained brown pycnidia within and extending along lesion-free sections of the stems and basal portions of leaves. Diseased stems were cut into 3- to 5-mm pieces and disinfested in 70% ethyl alcohol. After drying, stem pieces were placed into petri dishes on the surface of potato glucose agar. Numerous, dark, immersed erumpent pycnidia with a single ostiole were observed in all lesions after 2 to 3 days. Axenic cultures were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Ft. Detrick, MD for testing in quarantine. Conidiophores were simple, cylindrical, and 5 to 25 × 2 μm (mean 12 × 2 μm). Alpha conidia were biguttulate, one-celled, hyaline, nonseptate, ovoid, and 6.3 to 11.5 × 1.3 to 2.9 μm (mean 8.8 × 2.0 μm). Beta conidia were one-celled, filiform, hamate, hyaline, and 11.1 to 24.9 × 0.3 to 2.5 μm (mean 17.7 × 1.2 μm). The isolate was morphologically identified as a species of Phomopsis, the conidial state of Diaporthe (1). The teleomorph was not observed. A comparison with available sequences in GenBank using BLAST found 528 of 529 identities with the internal transcribed spacer (ITS) sequence of an authentic and vouchered Diaporthe eres Nitschke (GenBank DQ491514; BPI 748435; CBS 109767). Morphology is consistent with that of Phomopsis oblonga (Desm.) Traverso, the anamorph of D. eres (2). Healthy stems and leaves of 10 30-day-old plants of S. tragus were spray inoculated with an aqueous suspension of conidia (1.0 × 106 alpha conidia/ml plus 0.1% v/v polysorbate 20) harvested from 14-day-old cultures grown on 20% V8 juice agar. Another 10 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity (rh) for 16 h with no lighting at 25°C. After approximately 24 h, plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% rh, and natural light. Stem lesions developed on three inoculated plants after 14 days and another three plants after 21 days. After 70 days, all inoculated plants were diseased, four were dead, and three had more than 75% diseased tissue. No symptoms occurred on control plants. The Phomopsis state was recovered from all diseased plants. This isolate of D. eres is a potential biological control agent of S. tragus in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878717). Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2) were deposited in GenBank (Accession No. EU805539). To our knowledge, this is the first report of stem canker on S. tragus caused by D. eres. References: (1) B. C. Sutton. Page 569 in: The Coelomycetes. CMI, Kew, Surrey, UK, 1980. (2) L. E. Wehmeyer. The Genus Diaporthe Nitschke and its Segregates. University of Michigan Press, Ann Arbor, 1933.

scholarly journals First Report of Leaf Rust of Blueberry Caused by Thekopsora minima on Vaccinium corymbosum in the Western Cape, South Africa

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 478-478 ◽  
Author(s):  
L. Mostert ◽  
W. Bester ◽  
T. Jensen ◽  
S. Coertze ◽  
A. van Hoorn ◽  
...  
Keyword(s):  
South Africa ◽  
South African ◽  
Water Solution ◽  
Phylogenetic Analyses ◽  
The United States ◽  
Vaccinium Corymbosum ◽  
Tween 20 ◽  
Western Cape ◽  
The South ◽  
First Report

Southern highbush blueberry plants (Vaccinium corymbosum interspecific hybrids) showing rust-like symptoms were observed in July 2006 in Porterville in the Western Cape (WC), South Africa. Diseased plants were also found in Villiersdorp and George in the WC in 2007. In 2008, symptoms were observed in George, and in 2009, in all the previous reported areas. Cvs. Bluecrisp, Emerald, Jewel, Sharpblue, and Star were infected. Reddish-to-brown spots appeared on the adaxial surface of leaves and developed into yellow-to-orange erumpent uredinia with pulverulent urediniospores. Uredinia were hypophyllous, dome shaped, 113 to 750 μm wide, and occasionally coalescing. Urediniospores were broadly obovate, sometimes ellipsoidal or pyriform, with yellowish orange content, and measured 19 to 27 × 12 to 20 μm (average 24 × 15 μm, n = 30). Spore walls were echinulate, hyaline, 1 to 1.5 μm thick, and with obscure germ pores. No telia or teliospores were observed. Voucher specimens were lodged in the South African National Fungus Collection in Pretoria (PREM 60245). The isolate was initially identified as Thekopsora minima P. Syd. & Syd., based primarily on the absence of conspicuous ostiolar cells characteristic of Naohidemyces spp. (3). Genomic DNA was extracted from urediniospores. Approximately 1,400 bp were amplified spanning the 5.8S, ITS2, and 28S large subunit of the ribosomal DNA (1). The sequence (GU355675) shared 96% (907 of 942 bp; GenBank AF522180) and 94% (1,014 of 1,047 bp; GenBank DQ354563) similarities in the 28S portion, respectively, to those of Naohidemyces vaccinii (Wint.) Sato, Katsuya et Y. Hiratsuka and Pucciniastrum geoppertianum (Kuehn) Kleb, two of the three known rust species of blueberry (2). Although no sequences of T. minima were available for direct comparison, phylogenetic analyses of the 28S region strongly supported the South African blueberry rust as congeneric with T. guttata (J. Schröt.) P. Syd. & Syd. (GenBank AF426231) and T. symphyti (Bubák) Berndt (GenBank AF26230) (data not shown). Four 6-month-old cv. Sharpblue plants were inoculated with a suspension (approximate final concentration of 1 × 105 spores per ml) of fresh urediniospores in a water solution with 0.05% Tween 20. After incubation at 20°C for 48 h under continuous fluorescent lighting, the plants were grown in a glasshouse (18/25°C night/day temperatures). Identical uredinia and symptoms developed approximately 3 weeks after inoculation on the inoculated plants, but not on two control plants of cv. Sharpblue sprayed with distilled water and kept at the same conditions. The alternate host hemlock (Tsuga spp.) is not endemic to South Africa and not sold as an ornamental plant according to a large conifer nursery. Hosts of T. minima include Gaylussacia baccata, G. frondosa, Lyonia neziki, Menziesia pilosa, Rhododendron canadense, R. canescens, R. lutescens R. ponticum, R. prunifolium, R. viscosum, V. angustifolium var. laevifolium, V. corumbosum, and V. erythrocarpon (3). Visual inspection of possible hosts in the gardens in close proximity of Vaccinium production areas did not show any rust symptoms. To our knowledge, this is the first report of T. minima on blueberries outside of Asia and the United States (2). References: (1) M. C. Aime. Mycoscience 47:112, 2006. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. USDA-ARS, 2009. (3) S. Sato et al. Trans. Mycol. Soc. Jpn. 34:47, 1993.

scholarly journals First Report of Leaf Blight and Stem Canker of Pachysandra terminalis Caused by Pseudonectria pachysandricola in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287
Author(s):  
K. S. Han ◽  
J. H. Park ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
United States ◽  
Its Region ◽  
Stem Canker ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
First Report ◽  
Cornell University ◽  
Plastic Bags ◽  
Young Leaves

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 106 conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

scholarly journals First Report of Medical Tree Peony Root Rot Caused by Fusarium solani in Tongling, China

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 909-909 ◽  
Author(s):  
M. Guo ◽  
Y. M. Pan ◽  
Z. M. Gao
Keyword(s):  
Fusarium Solani ◽  
Root Rot ◽  
Tap Water ◽  
Blood Stasis ◽  
The United States ◽  
Effective Control ◽  
Conidial Suspension ◽  
Tree Peony ◽  
First Report ◽  
Peony Root

Tree peony bark, a main component of Chinese traditional medicine used for alleviating fever and dissipating blood stasis, is mainly produced in Tongling, China. Recently, tree peony cultivation in this area was seriously affected by root rot, with approximately 20 to 30% disease incidence each year. The disease severely affects yield and quality of tree peony bark. During the past 2 years, we collected 56 diseased tree peony plants from Mudan and Fenghuang townships in Tongling. We found reddish brown to dark brown root rot in mature roots, especially on those with injuries. Plant samples collected were disinfected with 2% sodium hypochlorite and isolations were conducted on potato sucrose agar (PSA). Eleven isolates were obtained and all had white fluffy aerial hypha on PSA. Two types of conidia were produced; the larger, reaphook-shaped ones had three to five septa and the smaller, ellipse-shaped ones had one or no septum. The reaphook-shaped conidia were 20.15 to 37.21 × 3.98 to 5.27 μm and the ellipse-shaped conidia were 6.02 to 15.52 × 2.21 to 5.33 μm in size. Chlamydospores were produced, with two to five arranged together. Biological characteristics of the fungi indicated that the optimum temperature for the mycelial growth on PSA was 25 to 30°C and the optimum pH range was 5.5 to 7.0. The above morphological characteristics point the fungal isolates to be Fusarium solani. To confirm pathogenicity, 30 healthy 1-year-old tree peony seedling plants were grown in pots (25 cm in diameter) with sterilized soil and a conidial suspension from one isolate (FH-1, 5 × 105 conidia/ml) was used for soil inoculation. Inoculated seedlings were maintained at 28°C in a greenhouse with a 12-h photoperiod of fluorescent light. Seedlings inoculated with distilled water were used as controls. After 3 weeks, the roots were collected and rinsed with tap water. Dark brown lesions were observed in the inoculated mature roots but not in the control roots. To confirm the identity of the pathogen, F. solani strains were reisolated from the lesions and total genomic DNA was extracted with the cetyltriethylammnonium bromide method from the mycelia of the reisolated strains (1). PCR was performed using the fungal universal primers ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) and ITS5 (5′-GGAAGTAAAAGTCGTAACAAGG-3′) to amplify a DNA fragment of approximately 590 bp. The purified PCR products were sequenced (Invitrogen Co., Shanghai, China) and shared 100% sequence identity with each other. A comparison of the sequence (JQ658429.1) by the Clustal_W program (2) with those uploaded in GenBank confirmed with the fungus F. solani (100% sequence similarity to isolate S-0900 from the Great Plains of the United States; EU029589.1). To our knowledge, this is the first report of F. solani causing medical tree peony root rot in China. The existence of this pathogen in China may need to be considered for developing effective control strategies. References: (1). C. N. Stewart et al. Biotechniques 14:748, 1993. (2). J. D. Thompson et al. Nucleic Acids Res. 22:4673, 1994.

scholarly journals First Report of Stem Canker of Goldenrain Tree Caused by Lasiodiplodia theobromae in Tennessee and the United States

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 3062-3062
Author(s):  
F. Baysal-Gurel ◽  
F. A. Avin ◽  
Cansu Oksel ◽  
T. Simmons
Keyword(s):  
United States ◽  
Stem Canker ◽  
The United States ◽  
Lasiodiplodia Theobromae ◽  
First Report

scholarly journals First Report of Alternaria tenuissima Causing Postharvest Decay on Apple Fruit from Cold Storage in the United States

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 690-690 ◽  
Author(s):  
L. P. Kou ◽  
V. L. Gaskins ◽  
Y. G. Luo ◽  
W. M. Jurick
Keyword(s):  
United States ◽  
South Africa ◽  
Cold Storage ◽  
Fungal Pathogens ◽  
The United States ◽  
Apple Fruit ◽  
Conidial Suspension ◽  
Single Spore ◽  
Alternaria Tenuissima ◽  
First Report

Apples are grown and stored for 9 to 12 months under controlled atmosphere conditions in the United States. During storage, apples are susceptible to various fungal pathogens, including several Alternaria species (2). Alternaria tenuissima (Nees) Wiltshire causes dry core rot (DCR) on apples during storage and has recently occurred in South Africa (1). Losses range widely, but typically occur at 6 to 8% annually due to this disease (2). In February 2013, ‘Nittany’ apples with round, dark-colored, dry, spongy lesions were obtained from wooden bins in a commercial cold storage facility located in Pennsylvania. Symptomatic fruits were transported to the lab, rinsed with sterile water, and the lesions were sprayed with 70% ethanol until runoff and wiped dry. The skin was aseptically removed with a scalpel, and asymptomatic tissue was placed onto potato dextrose agar (PDA) and incubated at 25°C. Two single-spore isolates were propagated on PDA and permanent cultures were maintained as slants and stored at 4°C. The fungus produced a cottony white mycelium that turned olive-green to brown with abundant aerial hyphae and had a dark brown to black reverse on PDA. Isolates were identified as Alternaria based on conidial morphology as the spores were slightly melanized and obclavate to obpyriform catentulate with longitudinal and transverse septa attached in unbranched chains on simple short conidiophores. Conidia ranged from 10 to 70 μm long (mean 27.7 μm) and 5 to 15 μm wide (mean 5.25 μm) (n = 50) with 1 to 6 transverse and 0 to 2 longitudinal septa. Conidial beaks, when present, were short (5 μm or less) and tapered. Mycelial genomic DNA was extracted, and a portion of the histone gene (357 bp) was amplified via gene specific primers (Alt-His3-F/R) using conventional PCR (Jurick II, unpublished). The forward and reverse sequences were assembled into a consensus representing 2× coverage and MegaBLAST analysis showed that both isolates were 100% identical to Alternaria tenuissima isolates including CR27 (GenBank Accession No. AF404622.1) that caused DCR on apple fruit during storage in South Africa. Koch's postulates were conducted using 10 organic ‘Gala’ apple fruit that were surface sterilized with soap and water, sprayed with 70% ethanol, and wiped dry. The fruit were aseptically wounded with a nail to a 3 mm depth, inoculated with 50 μl of a conidial suspension (1 × 104 conidia/ml), and stored at 25°C in 80 count boxes on paper trays for 21 days. Mean lesion diameters on inoculated ‘Gala’ apple fruit were 19.1 mm (±7.4), water only controls (n = 10 fruit) were symptomless, and the experiment was repeated. Symptoms observed on artificially inoculated ‘Gala’ apple fruit were similar to the decay observed on ‘Nittany’ apples from cold storage. Based on our findings, it is possible that A. tenuissima can cause decay that originates from wounded tissue in addition to dry core rot, which has been reported (1). Since A. tenuissima produces potent mycotoxins, even low levels of the pathogen could pose a health problem for contaminated fruit destined for processing and may impact export to other countries. To the best of our knowledge, this is the first report of alternaria rot caused by A. tenuissima on apple fruit from cold storage in the United States. References: (1) J. C. Combrink et al. Decid. Fruit Grow. 34:88, 1984. (2) M. Serdani et al. Mycol. Res. 106:562, 2002. (3) E. E. Stinson et al. J. Agric. Food Chem. 28:960, 1980.

scholarly journals First Report of Fusarium solani on Utah Sweetvetch in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 423-423 ◽  
Author(s):  
S. Uppala ◽  
B. M. Wu ◽  
T. N. Temple
Keyword(s):  
Native American ◽  
Fusarium Solani ◽  
Vascular Tissue ◽  
Agricultural Research ◽  
Apical Cell ◽  
The United States ◽  
Conidial Suspension ◽  
Soil Dna ◽  
First Report ◽  
Fungal Isolates

Utah sweetvetch (Hedysarum boreale Nutt.) is a native American perennial nitrogen fixing legume used mainly in rangeland reclamation, soil rejuvenation, and erosion control. In June 2011, a field of Utah sweetvetch grown for seeds in central Oregon had approximately 15% of the plants exhibiting chlorosis, defoliation, stunting, wilting, and/or death. Dissection of the crown of symptomatic plants revealed discolored pinkish brown vascular tissue. Symptomatic tissues from six random plants were surface sterilized, placed on acidified potato dextrose agar (PDA) medium, and cultured for 7 days at room temperature, which allowed six fungal isolates (SS1 through SS6) to be collected. On PDA, all six isolates had rapid, creamy white colored growth. Based on observations of 1-week-old isolates, microconidia were oval to kidney shaped, single celled, 8 to 10 × 2.5 to 4 μm, and formed at the tips of long unbranched monophialides. Macroconidia were three to four septate, cylindrical to slightly curved, with characteristic foot shaped basal cell and blunt apical cell, 37 to 49 × 4.4 to 5.3 μm. Chlaymydospores observed were 8.5 to 11 × 7.6 to 9 μm. Based on fungal references (1,2,3), the isolates were identified as Fusarium solani (Mart.) Sacc. Identification of the isolates at the molecular level was determined by amplification of the internal transcribed spacer (ITS) region using PCR and amplicon sequencing. Botrytis cinerea and F. graminearum cultures were used as controls for the extraction, amplification, and sequencing steps. Genomic DNA was extracted from mycelia using protocols of the MOBIO Ultraclean Soil DNA Isolation Kit (MO-BIO Laboratories Inc, Carlsbad, CA, USA). PCR was performed using ITS1/ITS4 primers and resulted in 563- to 573-bp amplicons, which were sequenced. Analysis of the ITS sequences (GenBank Accession Nos. JX524018 to JX524023) for the six fungal isolates using BLASTn revealed a 99% sequence identity with F. solani strains (AB470903, AB513851, AJ608989, EF152426, EU029589, and HM214456). Pathogenicity was confirmed on Utah sweetvetch plants in the greenhouse. Seeds of Utah sweetvetch were first plated on acidified PDA for germination; healthy seedlings were then selected and transplanted into pots with sterilized soil after 2 weeks of growth. The plants were kept in a greenhouse at Central Oregon Agricultural Research Center, Madras, Oregon. Ten 40-day-old healthy vetch plants were inoculated by drenching with a mixed conidial suspension (107 conidia/ml) of the six F. solani isolates. Ten plants drenched with sterile distilled water were included as controls. Symptoms of chlorosis and stunting similar to those in the commercial field were observed within 30 days of inoculation on 8 of 10 inoculated plants, while control plants were symptomless. Fungal isolates identical to F. solani were reisolated from the symptomatic plants. To our knowledge, this is the first report of F. solani on Utah sweetvetch plants. References: (1) C. Booth. The Genus Fusarium. CMI, Kew, Surrey, UK, 1971. (2) P. E. Nelson et al. Fusarium species: An illustrated manual for identification. The Pennsylvania State University Press, USA, 1983. (3) H. I. Nirenberg. A simplified method for identifying Fusarium spp. occurring on wheat. Can. J. Bot. 59:1599, 1980.

First Report of Alternaria alternata and Fusarium spp. Causing Brown Apical Necrosis in Walnut Fruit in Southern Chile

2021 ◽  
Author(s):  
Ernesto Antonio Moya-Elizondo ◽  
María Jose Lagos ◽  
Juan G. San Martín ◽  
Braulio E. Ruiz
Keyword(s):  
Alternaria Alternata ◽  
Fungal Pathogens ◽  
Juglans Regia ◽  
Bacterial Pathogen ◽  
Southern Chile ◽  
Fusarium Spp ◽  
First Report ◽  
Fruit Drop ◽  
English Walnut ◽  
Apical Necrosis

This is the first report of Alternaria alternata and Fusarium spp. causing brown apical necrosis (BAN) in walnut fruit in southern Chile. English walnut (Juglans regia L.) is the second most widely grown fruit in Chile. The bacterial pathogen Xanthomonas arboricola pv. juglandis affects walnut production in Chile and has been associated with apical necrosis symptom and premature fruit drop; this research focused on determining if fungal pathogens were associated with this damage. The presence of BAN in commercial walnut orchards in southern Chile reveals the need for improved phytosanitary programs to control this disease.

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