Effects of silver scurf (Helminthosporium solani) on seed potatoes

1984 ◽  
Vol 27 (2) ◽  
pp. 145-154 ◽  
Author(s):  
P. J. Read ◽  
G. A. Hide
Keyword(s):  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Seed Potatoes

scholarly journals Occurrence and epidemiological aspects of potato silver scurf in California

2004 ◽  
Vol 22 (4) ◽  
pp. 690-695 ◽  
Author(s):  
Marcos G. Cunha ◽  
David M. Rizzo
Keyword(s):  
Storage Period ◽  
Storage Conditions ◽  
Silver Scurf ◽  
Inoculum Potential ◽  
Helminthosporium Solani ◽  
Potato Tubers ◽  
Commercial Potato ◽  
Tuber Disease ◽  
Fusarium Sp ◽  
Over Time

A new potato tuber disease has been observed in the Tulelake region, California, USA, since 1995, with tuber symptoms suggestive of silver scurf disease (Helminthosporium solani). In this work we isolated, identified and demonstrated the nature of the causal agent of this potato disease in California. In addition, the distribution of H. solani in potato fields and the inoculum potential at harvest time were investigated. Disease progress and H. solani spore populations were also characterised under commercial storage conditions. The main fungal genera associated with potato tubers in storage were Helminthosporium solani, Colletotrichum sp., Fusarium sp., and Rhizoctonia sp. The results of Koch's postulates indicated that H. solani is responsible for the outbreak of silver scurf in the Tulelake region. In a disease survey in three commercial potato fields naturally infested, H. solani infections occurred in all fields. However, the extension of the infections differed significantly between the fields. During potato storage, silver scurf usually increased over time. The percentage of the tuber surface covered by silver scurf varied from 3.5% up to 35.5% during the storage period. The number of H. solani lesions per tuber also progressively increased from 6% up to 35%, six months after storage. H. solani spore populations also increased over time in all studied potato stores; nevertheless, they followed no consistent pattern, exhibiting multiple and variable peaks of increase and reduction during the period of storage.

scholarly journals Potato Silver Scurf Affected by Tuber Seed Treatments and Locations, and Occurrence of Fungicide Resistant Isolates of Helminthosporium solani

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 315-320 ◽  
Author(s):  
Brad Geary ◽  
Dennis A. Johnson ◽  
Philip B. Hamm ◽  
Steve James ◽  
Ken A. Rykbost
Keyword(s):  
Seed Tuber ◽  
Disease Incidence ◽  
Geographic Origin ◽  
Small Scale ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Columbia Basin ◽  
Thiophanate Methyl ◽  
First Report ◽  
Production Area

The effectiveness of various seed-tuber treatments was evaluated for control of silver scurf on potato (Solanum tuberosum), caused by Helminthosporium solani, at four locations in Washing-ton and Oregon using seed-tubers from the same source. Disease incidence was determined at harvest and following storage, and differed significantly among locations. The highest incidence of disease was observed at Redmond, OR and the lowest was at Hermiston, OR. Significantly less silver scurf occurred on progeny-tubers, regardless of location, when seed was treated with the fungicide treatments fludioxonil, fludioxonil + quintozene, azoxystrobin, or thiophanate-methyl + mancozeb compared with the nontreated control. A sample of H. solani from seed planted in the Columbia Basin of Washington and Oregon was assessed for resistance to thia-bendazole (TBZ) and thiophanate-methyl (TPM). Sensitivity of 20 isolates of H. solani to TBZ was determined on V8 media amended with TBZ. Four isolates, selected as a subset from the 20 isolates tested for TBZ sensitivity, were tested for resistance to TPM, mancozeb, and TPM + mancozeb on amended V8 media. Isolates differed significantly in sensitivity to both chemicals. Thirteen isolates out of the 20 tested were resistant to TBZ. One out of the four subsets of isolates was resistant to both TBZ and TPM. TBZ sensitivity was not related to geographic origin of the isolates. Variation in resistance was evident on a small scale as seen with one resistant and one sensitive isolate collected from the same tuber. This is the first report that silver scurf incidence is affected by location despite the same tuber-seed source and also the first report of TBZ and TPM resistant isolates of H. solani from the Columbia Basin (Oregon and Washington) production area.

scholarly journals Evaluation of different fungicides applied as seed tuber treatments for the control of potato silver scurf

2005 ◽  
Vol 82 (2) ◽  
pp. 41-48 ◽  
Author(s):  
V. Hervieux ◽  
R. Chabot ◽  
J. Arul ◽  
R.J. Tweddell
Keyword(s):  
Solanum Tuberosum ◽  
Seed Tuber ◽  
Field Trials ◽  
Potato Seed ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Potato Tubers ◽  
Experimental Conditions ◽  
Soil Inoculum ◽  
Seed Tubers

Silver scurf of potatoes (Solanum tuberosum), caused by the fungus Helminthosporium solani, is an important surface-blemishing disease of potato tubers. The objective of the study was to evaluate the efficacy of different fungicides applied to potato seed tubers for control of silver scurf. Field trials were conducted in Québec province in 1998 and 1999. Potato seed tubers infected with H. solani were treated with either talc, fludioxonil, mancozeb, iprodione, thiabendazole, imazalil or azoxystrobin, and planted at three locations in 1998 and two locations in 1999. The results showed that, under our experimental conditions, the fungicides tested, applied as seed treatments, did not significantly influence total and marketable yields as well as silver scurf severity on daughter tubers at harvest and after different storage periods. In addition, this study showed the influence of the experimental locations on silver scurf development and suggests that soil inoculum plays a role in the epidemiology of the disease.

Transmission of Helminthosporium solani from potato seed tubers and effects of soil conditions, seed inoculum and seed physiology on silver scurf disease

1995 ◽  
Vol 124 (2) ◽  
pp. 219-234 ◽  
Author(s):  
D. M. Firman ◽  
E. J. Allen
Keyword(s):  
Weight Loss ◽  
Field Experiments ◽  
Soil Conditions ◽  
Potato Seed ◽  
Silver Scurf ◽  
Moisture Regime ◽  
Helminthosporium Solani ◽  
Seed Tubers ◽  
Soil Moisture Regime ◽  
One Year

SUMMARYThe transmission of silver scurf (Helminthosporium solani) disease of potatoes was examined in field experiments at Cambridge University Farm in 1988–90. Treatment factors examined were seed size, seed age, seed incubation, soil moisture regime and planting date. A laboratory experiment investigated the viability of conidia of Helminthosporium in soil stored under different conditions.Incubation of seed at high humidity before planting increased sporulation of Helminthosporium on seed tubers after planting and fewer conidia were produced from small seed than from larger seed. Delay in planting caused more rapid growth of Helminthosporium on seed tubers after planting.Early planting and late harvesting increased the severity of silver scurf on progeny tubers. Severity of silver scurf was also increased by ageing seed and by incubating seed. Weight loss of potato tubers during storage tended to be greater from treatments with most severe silver scurf in all years but a significant linear regression of weight loss on silver scurf severity was found in only one year out of three from a late harvest. The viability of conidia added to soil was found to decrease rapidly so that by 10 weeks after addition, < 1% of conidia were apparently viable.

Helminthosporium solani. [Descriptions of Fungi and Bacteria].

1968 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Solanum Tuberosum ◽  
Geographical Distribution ◽  
Storage Conditions ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Potato Tubers ◽  
Entire Surface ◽  
Infected Seed ◽  
Seed Tubers ◽  
Large Numbers

Abstract A description is provided for Helminthosporium solani. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Solanum tuberosum. DISEASE: Silver scurf of potato tubers. It causes a blemish of the skin which becomes discoloured brown or silvery in patches, more conspicuous in spring especially on greened tubers. The silvery appearance is most apparent when tubers are washed. Sometimes the affected areas become dry and flake-off. Where infection is severe under storage conditions the entire surface of the tuber may become sooty owing to the presence of large numbers of conidiophores and conidia. GEOGRAPHICAL DISTRIBUTION: CMI Map 233 shows distribution up to 1951. Countries from which the disease has been reported since then include: Greece, India, Jersey, Mozambique, Peru, Switzerland, U.S.S.R., Venezuela. TRANSMISSION: Through infected seed tubers.

scholarly journals A Three-Way Transcriptomic Interaction Study of a Biocontrol Agent (Clonostachys rosea), a Fungal Pathogen (Helminthosporium solani), and a Potato Host (Solanum tuberosum)

2017 ◽  
Vol 30 (8) ◽  
pp. 646-655 ◽  
Author(s):  
Erik Lysøe ◽  
Merete W. Dees ◽  
May Bente Brurberg
Keyword(s):  
Gene Expression ◽  
Defense Mechanisms ◽  
Cellular Response ◽  
Biocontrol Agent ◽  
Mitogen Activated Protein Kinase ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Protein Signaling ◽  
Clonostachys Rosea ◽  
Mitogen Activated Protein

Helminthosporium solani causes silver scurf, which affects the quality of potato. The biocontrol agent Clonostachys rosea greatly limited the severity of silver scurf symptoms and amount of H. solani genomic DNA in laboratory experiments. Transcriptomic analysis during interaction showed that H. solani gene expression was highly reduced when coinoculated with the biocontrol agent C. rosea, whereas gene expression of C. rosea was clearly boosted as a response to the pathogen. The most notable upregulated C. rosea genes were those encoding proteins involved in cellular response to oxidative stress, proteases, G-protein signaling, and the methyltransferase LaeA. The most notable potato response to both fungi was downregulation of defense-related genes and mitogen-activated protein kinase kinase kinases. At a later stage, this shifted, and most potato defense genes were turned on, especially those involved in terpenoid biosynthesis when H. solani was present. Some biocontrol-activated defense-related genes in potato were upregulated during early interaction with C. rosea alone that were not triggered by H. solani alone. Our results indicate that the reductions of silver scurf using C. rosea are probably due to a combination of mechanisms, including mycoparasitism, biocontrol-activated stimulation of plant defense mechanisms, microbial competition for nutrients, space, and antibiosis.

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