scholarly journals First Report of Fusarium graminearum Causing Dry Rot of Potato in North Dakota

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 105-105 ◽  
Author(s):  
S. Ali ◽  
V. V. Rivera ◽  
G. A. Secor

Fusarium dry rot of potato can be caused by several species of Fusarium, but F. sambucinum is considered the primary cause in stored potatoes in North America and Europe (2). Potato tubers of cvs. Shepody and Russet Burbank with severe dry rot were collected from a commercial processing storage facility in central North Dakota during 2003–2004. Pathogen isolations were made from infected tubers on one-half strength acidified potato dextrose agar (APDA). Only F. graminearum was isolated from all rotted tubers used. Identification was based on colony morphology and conidial and perithecial characteristics, which included a carmine coloration of the underside of the agar and white fluffy mycelium on APDA, the presence of black perithecia on carnation leaf agar, and large distinctive macroconidia (1). The identity was confirmed by the Fusarium Research Institute at Pennsylvania State University. Pathogenicity was tested in potato tubers and greenhouse-grown potato plants cv. Atlantic. Nine tubers were wounded by removal of a plug of tissue with a cork borer, 3 mm in diameter and 5 mm deep, and inoculated by placing either 100 μl of a conidial suspension (5 × 104 conidia per ml) from a 7-day-old culture or a mycelial plug, 3 mm in diameter, from a 7-day-old culture in the wound. Nine tubers wounded and treated with either sterile distilled water or one-half strength APDA served as controls. Plant inoculations were performed by cutting a slit in the lower stem with a sterile scalpel and placing a cotton collar saturated with a conidial suspension (5 × 104 conidia per ml) around the wound and held in place with a clothespin. Four plants were inoculated with a conidial suspension, and four plants were treated with sterile distilled water. All tubers inoculated with either Fusarium treatment developed typical potato dry rot symptoms consisting of a brown, dry decay with mycelium lined cavities, and F. graminearum was reisolated from all symptomatic tubers. The control tubers did not develop symptoms. No symptoms developed in any of the greenhouse inoculated plants. Fifteen isolates were tested for sensitivity to thiabendazole, and all were sensitive with EC50 (50% effective concentration) values ranging from 0.8 to 3.7 μl/ml. The results indicate that F. graminearum can cause dry rot of potato, and to our knowledge, this is the first report of F. graminearum as a cause of potato dry rot. These results have epidemiological implications in the persistence, spread, and management of F. graminearum in cereals and potatoes, since potato is often used in rotation with other hosts of F. graminearum, including wheat, barley, and corn. References: (1) P. E. Nelson et al. Pages 118–119 in: Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University, University Park and London, 1983. (2) G. A. Secor and B. Salas. Fusarium dry rot and fusarium wilt. Pages 23–25 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson, R. Loria, G. D. Franc, and D. P. Weingartner, eds. The American Phytopathological Society, St. Paul, MN, 2001.

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1194-1194 ◽  
Author(s):  
E. Gachango ◽  
W. Kirk ◽  
L. Hanson ◽  
A. Rojas ◽  
P. Tumbalam

Fusarium dry rot of potato (Solanum tuberosum L.) is a postharvest disease caused by several Fusarium species and is of worldwide importance. Thirteen species of Fusarium have been implicated in fungal dry rots of potatoes worldwide. Among them, eight species have been reported in the northern United States (2). In Michigan potato production, F. sambucinum was the predominant species reported to be affecting seed potato in storage and causing seed piece decay after planting (3). Some previous identifications of F. sambucinum as dry rot may have been F. torulosum since F. torulosum was previously classified within F. sambucinum (4). To further investigate this, dry rot symptomatic tubers were collected from Michigan seed lots in the summers of 2009 and 2010. Small sections from the margins of necrotic regions were cut with a scalpel, surface sterilized in 0.5% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and blotted with sterile filter paper. The tissue pieces were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate and incubated at 23°C for 5 to 7 days. Cultures resembling Fusarium species were transferred onto water agar, and single hyphal tips from actively growing isolates were removed and plated either on carnation leaf agar (CLA) or on half-strength PDA to generate pure cultures. Among the Fusarium isolates obtained, five isolates were identified as F. torulosum (GenBank Accessions Nos. JF803658–JF803660). Identification was based on colony and conidial morphology on PDA and CLA, respectively. These features included slow growth (2.8 ± 0.2 cm in 5 days), white mycelium that became pigmented with age, narrow concentric rings, red or white pigmentation on agar, macroconidia (32.4 ± 0.4 μm average length) with five septa, a pointed apical cell, and a foot-shaped basal cell (4). The identity was confirmed through DNA extraction followed by amplification and sequencing of the translation elongation factor (EF-1α) gene region (1). The Fusarium-ID.v (1) and the NCBI database were used to obtain the closest match (99%) to previously sequenced materials (GenBank Accession No. AJ543611). Pathogenicity testing was done on disease-free potato tubers cv. Red Norland. Tubers were surface sterilized for 10 min in 0.5% sodium hypochlorite and rinsed twice in distilled water. Three tubers per isolate were injected with 20 μl of a conidial suspension (106 conidia/ml) made from F. torulosum cultures grown on PDA for 7 to 10 days. Control tubers were injected with 20 μl of sterile distilled water. All tubers inoculated with F. torulosum developed typical potato dry rot symptoms consisting of a brown and dry decay. There was no disease incidence on the control tubers. F. torulosum was reisolated from the symptomatic tubers. To our knowledge, this is the first report of F. torulosum causing potato dry rot in the United States. References: (1) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) L. E. Hanson et al. Phytopathology 86:378, 1996. (3) M. L. Lacy and R. Hammerschmidt. Fusarium dry rot. Extension Bulletin. Retrieved from http://web1.msue.msu.edu/msue/iac/onlinepubs/pubs/E/E2448POT , 23 May 2010. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Wiley-Blackwell, Hoboken, NJ, 2006.


Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 843-843
Author(s):  
A. Merlington ◽  
L. E. Hanson ◽  
R. Bayma ◽  
K. Hildebrandt ◽  
L. Steere ◽  
...  

Fusarium dry rot of potato (Solanum tuberosum L.) is a postharvest disease caused by several Fusarium spp. Thirteen Fusarium spp. have been implicated in dry rot of potatoes worldwide. Among them, 11 species have been reported causing potato dry rot of seed tubers in the northern United States (1). Historically, Fusarium sambucinum was the predominant species in Michigan potato production (3). Dry rot symptomatic tubers (n = 972) were collected from Michigan commercial potato storage facilities in 2011 and 2012 to determine the composition of Fusarium spp. Sections were cut from the margins of necrotic tissue with a sterile scalpel and surface disinfested in 0.6% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and dried on sterile filter paper. The tissue sections were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate. Dishes were incubated at 23°C in the dark for 7 days. Putative Fusarium isolates were transferred onto water agar and hyphal tips from the margin of actively growing cultures were removed with a sterile scalpel and plated to carnation leaf agar (CLA) and half-strength PDA to generate pure cultures. Seven hundred and thirty Fusarium isolates were collected using these techniques. Preliminary identification of the 730 isolates was based on colony and conidial morphology on PDA and CLA, respectively. While F. oxysporum and F. sambucinum were isolated as expected from prior reports (3), three isolates of F. proliferatum were also identified. On CLA, macroconidia of F. proliferatum were sparse, slender, and mostly straight, with three to five septae (4). Microconidia were abundant, usually single celled, oval or club-shaped in short chains or false heads on monophialides and polyphialides (4), and chlamydospores were absent. On PDA, abundant white mycelium was produced and turned violet with age. Koch's postulates were confirmed through pathogenicity testing on disease-free potato tubers cvs. Atlantic and Russet Norkotah. Tubers were surface disinfested for 10 min in 0.6% sodium hypochlorite and rinsed twice in distilled water. Three tubers of each cultivar per isolate were wounded at the apical end of the tuber to a depth of 4 to 10 mm with a 4 mm diameter cork-borer. Tubers were inoculated by inserting a mycelial plug from a 7-day-old culture grown on PDA into the wound and incubating the tubers at 20°C for 21 days. All Fusarium isolates were tested. Control tubers were inoculated by inserting a water agar plug. Pathogenicity and virulence testing were replicated three times and repeated. Tubers inoculated with F. proliferatum developed typical potato dry rot symptoms but no dry rot symptoms were observed on control tubers. Fusarium proliferatum was re-isolated from symptomatic tubers, confirming Koch's postulates. To our knowledge, this is the first report of F. proliferatum causing potato dry rot in Michigan. References: (1) E. Gachango et al. Plant Dis. 96:1767. (2) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (3) M. L. Lacy and R. Hammerschmidt. Fusarium dry rot. Extension Bulletin. Retrieved from http://web1.msue.msu.edu/msue/iac/onlinepubs/pubs/E/E2448POT, 23 May 2010. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Wiley-Blackwell, Hoboken, NJ, 2006.


Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 228-228 ◽  
Author(s):  
E. Gachango ◽  
W. Kirk ◽  
L. Hanson ◽  
A. Rojas ◽  
P. Tumbalam ◽  
...  

Fusarium dry rot of potato (Solanum tuberosum) is a postharvest disease caused by several Fusarium spp. Dry rot is managed primarily by reducing tuber bruising and promoting rapid wound healing. Dry rot symptomatic tubers were collected from Michigan seed lots in 2009 and 2010. The isolates may not have been exposed to fludioxonil because currently applications are restricted to seed not intended for seed production (3). Small sections were cut from the margins of necrotic regions with a scalpel, surface sterile in 10% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and blotted with sterile filter paper. The tissue pieces were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate. The dishes were incubated at 23°C for 5 to 7 days. Cultures resembling Fusarium spp. were transferred onto water agar and hyphal tips from the margin of actively growing isolates were removed with a sterile probe and plated either on carnation leaf agar (CLA) or on half-strength PDA to generate pure cultures. Fusarium isolates were obtained and used for further studies. Among them, 54 were identified as Fusarium oxysporum and 23 as F. sambucinum. Identification was based on colony and conidial morphology on PDA and CLA, respectively. The identity was confirmed through DNA extraction followed by amplification and sequencing of the translation elongation factor (EF-1α) gene region. The Fusarium-ID v. (2) and the NCBI database were used to obtain the closest match to previously sequenced materials. Pathogenicity testing was done on disease-free potato tubers, cv. FL 1879. Tubers were surface sterilized for 10 min in 10% sodium hypochlorite and rinsed twice in distilled water. Three tubers per isolate were injected with 20 μl of a conidial suspension (106 conidia/ml) made from cultures grown on PDA for 7 days. Control tubers were injected with 20 μl of sterile distilled water. All tubers inoculated with F. sambucinum and F. oxysporum developed typical potato dry rot symptoms consisting of dry brown decay lesions. F. sambucinum and F. oxysporum were reisolated from all symptomatic tubers. An effective concentration for 50% reduction in growth (EC50) was determined for each F. sambucinum and F. oxysporum isolate for thiabendazole (TBZ), fludioxonil, and difenoconazole using the spiral gradient endpoint method (1). Sensitive and resistant F. sambucinum and F. oxysporum isolates were reported. Fifteen isolates of F. sambucinum and thirty-four of F. oxysporum were resistant to fludioxonil with EC50 greater than 130 mg/liter. The remainder was sensitive to fludioxonil with EC50 ranging from 0.8 to 4.9 mg/liter. To our knowledge, this is the first report of resistance to fludioxonil in isolates of F. sambucinum and F. oxysporum in Michigan. Fusarium insensitivity in laboratory studies may not translate directly to commercial production. This disparity may result from interactions not experienced in mixed populations or within a living host. There has been no compelling evidence to suggest that fludioxonil has failed to perform because of insensitivity to Fusarium. The occurrence of such isolated strains necessitates the development and registration of partner chemistries that can preempt any future concerns on lack of performance of products in use. References: (1) H. Förster et al. Phytopathology 94:163, 2004. (2) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (3) R. D. Peters et al. Plant Dis. 92:172, 2008.


2019 ◽  
Vol 153 ◽  
pp. 69-78 ◽  
Author(s):  
Huali Xue ◽  
Yang Bi ◽  
Dov Prusky ◽  
Hussain Raza ◽  
Rui Zhang ◽  
...  

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1587-1587
Author(s):  
B. Singh ◽  
C. S. Kalha ◽  
V. K. Razdan ◽  
V. S. Verma

While screening newly introduced cultivars of walnut (Juglans regia) at Bhaderwah (Mini Kashmir), Jammu and Kashmir, India in September 2008, 60% of grafted plants were found to be dying because of a cankerous growth observed on seedling stems. Later, these symptoms extended to lateral branches. In the surveyed nurseries, cvs. SKU 0002 and Opex Dachaubaria were severely affected by the disease. Cankers were also observed in all walnut nurseries in the area with several wild seedlings also being observed to be exhibiting similar cankerous symptoms on stem and branches. Necrotic lesions from cankerous tissues on seedling stems were surface disinfested with 0.4% NaOCl for 1 min and these disinfected cankerous tissues were grown on potato dextrose agar (potato-250 g, dextrose-15 g, agar-15 g, distilled water-1 liter). A Fusarium sp. was isolated consistently from these cankerous tissues, which was purified using single-spore culture. Carnation leaf agar was used for further culture identification (2,3). The fungal colony was floccose, powdery white to rosy in appearance when kept for 7 days at 25 ± 2°C. Macroconidia were straight to slightly curved, four to eight septate and 30 to 35 × 3.5 to 5.7 μm. These are characteristics consistent with Fusarium incarnatum (3). Pathogenicity was confirmed by spraying a conidial suspension (1 × 106 conidia/ml) onto bruised branches of 1-year-old walnut plants (cv. Opex Dachaubaria) while sterile distilled water sprays were used for the controls. Inoculated plants were incubated at 20 ± 2°C and 85% relative humidity for 48 h. Fifty days following inoculation, branch dieback followed by canker symptoms developed on inoculated plants. Control plants remained healthy with no symptoms of canker. F. incarnatum (Roberge) Sacc. was repeatedly isolated from inoculated walnut plants, thus satisfying Koch's postulates. Infected plant material has been deposited at Herbarium Crytogamae Indiae Orientalis (ITCC-6874-07), New Delhi. To our knowledge, this is the first report of walnut canker caused by F. incarnatum (Roberge) Sacc. from India. This fungus was previously reported to be affecting walnut in Italy (1) and Argentina (4). References: (1) A. Belisario et al. Informatore Agrario 21:51, 1999. (2) J. C. Gilman. A Manual of Soil Fungi. The Iowa State University Press, Ames, 1959. (3) P. E. Nelson et al. Fusarium Species. An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, 1983. (4) S. Seta et al. Plant Pathol. 53:248, 2004.


Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1519-1519 ◽  
Author(s):  
W. H. Elmer ◽  
M. Daughtrey ◽  
K. Rane ◽  
M. M. Jimenez-Gasco

Disease symptoms were observed in a commercial nursery in the midwest on Coreopsis verticillata ‘Moonbeam’ during the summer of 2006. Plants in a roughly circular area in one field showed foliar necrosis, stem basal cankers, root rot, and eventually plant death. Vascular discoloration was noted in stems of affected plants. Sporulation typical of Fusarium oxysporum was observed on the surface of cankers. Five isolates of F. oxysporum (KR1, KR2, KR4, MDU, and MDL) were taxonomically identified from monosporic cultures obtained from surface-disinfested stems and roots. All five isolates were vegetatively compatible with each other. Two methods of inoculation were used. Method one (conidial drench) involved pouring 100 ml of conidial suspension (106 conidia per ml) into 10-cm pots containing one healthy 2-month-old division of the same cultivar that was obtained from a different nursery. Method two (millet infestation) involved mixing autoclaved millet seed that had been colonized by each isolate into potting mix (2.5 g/L of mix) prior to transplanting. Four plants were tested per isolate per method and controls received distilled water or autoclaved millet. After 3 months, only two isolates (KR1 and KR2) inoculated by conidial drench caused root rot, whereas all isolates inoculated by millet infestation caused wilt, root rot, and vascular discoloration, and all inoculated plants died after 3.5 months Controls remained healthy. The fungus was recovered and was vegetatively compatible with the original F. oxysporum isolates. The tef-α gene from two F. oxysporum isolates was sequenced, submitted to the Blast ID search at Pennsylvania State University (1), and found to belong to the F. oxysporum species complex. Two isolates (KR1 and KR 2) have been deposited at the Fusarium Research Center at Pennsylvania State University under deposition numbers O-2437 and O-2438. Because of the popularity of this coreopsis cultivar, this disease has the potential to cause significant economic loss in nurseries and landscape businesses. The affected nursery, however, has taken all precautions to avoid disseminating the pathogen. Reference: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004.


2000 ◽  
Vol 77 (1) ◽  
pp. 29-40 ◽  
Author(s):  
David A. Schisler ◽  
Patricia J. Slininger ◽  
Gale Kleinkopf ◽  
Rodney J. Bothast ◽  
Richard C. Ostrowski

Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1405-1405 ◽  
Author(s):  
G. Lori ◽  
S. Wolcan ◽  
C. Mónaco

During the summer of 1995-1996, an 80-ha field of 6-year-old asparagus plants (cv. UC 72) in Saladillo (Province of Buenos Aires) was affected by a decline syndrome (1). The plants showed a decline in vigor and approximately 60 to 70% of the plants died. The symptomatic plants were chlorotic, stunted, with stem lesions and crown and root rot. Fusarium moniliforme and F. proliferatum were isolated from vascular and epidermal tissues of roots, crowns, and stems. Identification of Fusarium to species was made by examining conidiogenous cells from colonies cultured on KCl medium (2). Microconidia were born in long and short chains and false heads. The isolates were identified based on the the presence of polyphialides in F. proliferatum and their absence in F. moniliforme, which produces monophialides only (2). In two separate trials, asparagus seeds (cv. UC 72) were surface sterilized and placed in steamed soil infested with a conidial suspension of each species. The viable propagules in the soil (CFU per g) were estimated by soil plate dilutions on Nash & Snyder-PCNB (pentachloronitrobenzene) medium. The F. moniliforme and F. proliferatum soil densities were 19.2 × 103 and 23 × 103 CFU per g of soil, respectively. The pots were placed in the greenhouse on different benches to avoid cross-contamination. After 4 months, inoculated plants showed root and crown discoloration. F. moniliforme and F. proliferatum were reisolated (64 and 75%, respectively) from discolored portions of internal and external root and crown tissues. Although the stems did not show symptoms, F. moniliforme and F. proliferatum were also recovered (27 and 38%, respectively) from asymptomatic tissues. Six months after inoculation the plants developed chlorotic symptoms with crown and root rot, and then wilted. F. moniliforme and F. proliferatum were reisolated from root systems, crowns, and stems of all inoculated plants. F. moniliforme and F. proliferatum are involved in corn stalk and ear rot in Argentina. Corn and asparagus are frequently grown in close proximity and often follow one another at a particular site. Airborne and soil debris carrying F. moniliforme and F proliferatum from corn may be an additional source of inoculum for asparagus in Argentina. The results indicate that the presence of F. moniliforme and F. proliferatum is a factor that contributes to asparagus decline in Argentina. References: (1) W. H. Elmer et al. Plant Dis. 80:117, 1996. (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University, University Park, 1983.


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