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.

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.

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.

Modelling the effects of potato seed-tuber age on plant establishment

1991 ◽  
Vol 71 (4) ◽  
pp. 1219-1232 ◽  
Author(s):  
N. Richard Knowles ◽  
Gabor I. Botar
Keyword(s):  
Solanum Tuberosum ◽  
Leaf Area ◽  
Seed Tuber ◽  
Weight Ratio ◽  
Dry Weight ◽  
Yield Component ◽  
Russet Burbank ◽  
Potato Seed ◽  
Plant Establishment ◽  
Seed Tubers

Four physiological ages of potato (Solanum tuberosum L. 'Russet Burbank') seed-tubers were produced by varying the time of storage at 15 °C. Age was quantified as the accumulated degree-days (dd) above 4 °C over the 199-d storage interval, and plant emergence and establishment were then modelled in controlled environment studies. As age advanced, time to 50% sprout emergence decreased, reaching a minimum at 589 dd, and then increased with further aging. Apical dominance was also reduced, as evident from a linear increase in the number of sprouts per seedpiece with advancing age. Earlier emergence from older seed-tubers led to significantly more leaves, leaf area, and leaf and stem dry weights per plant compared with younger seed-tubers early in the study; however, this advantage in plant establishment was eventually lost as time progressed through 33 d, resulting in significant age by time interactions on each yield component. Unit leaf rate, and relative growth rates with respect to leaf area and plant dry weight, thus decreased linearly with advancing tuber age over the course of the study. Leaf area ratio of plants from older tubers was greater than that from younger tubers early in the study, but this difference decreased with time. Seed-tuber age affected LAR through altering the leaf weight ratio (efficiency of partitioning dry weight to leaves), not the specific leaf area. Yield component analysis showed that the number of leaves per stem and the leaf area per leaf accounted for 85 and 12% of the total variation in plant dry weight, respectively. Because plant establishment was clearly more advanced, there may be potential for utilizing aged Russet Burbank seed-tubers to improve grade and earliness and increase yield in areas with short growing seasons. Key words: Solanum tuberosum, seed-tuber age, vigor, potato

scholarly journals Selection of Antagonist Microorganisms Against Helminthosporium solani, Causal Agent of Potato Silver Scurf

Plant Disease ◽  
2002 ◽  
Vol 86 (7) ◽  
pp. 717-720 ◽  
Author(s):  
M. Michaud ◽  
C. Martinez ◽  
A.-M. Simao-Beaunoir ◽  
R. R. Bélanger ◽  
R. J. Tweddell
Keyword(s):  
Seed Tuber ◽  
Control Strategies ◽  
Streptomyces Griseus ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Potato Tubers ◽  
Biocontrol Program ◽  
Individual Ability ◽  
Arcanobacterium Haemolyticum ◽  
Arthrobacter Oxydans

Silver scurf, caused by the fungus Helminthosporium solani, is an important disease affecting potato tubers. Control of the disease has been hampered by the development of H. solani strains resistant to thiabendazole, the only fungicide used in postharvest treatment. As a result, alternative control strategies are needed. In this study, 100 selected soil samples from the province of Québec were tested for their effect on silver scurf development on potato tubers. The results showed that 10 soils were able to decrease silver scurf development on tubers incubated at 10, 15, or 24°C. Many microorganisms were isolated from these soils and tested for their individual ability to reduce H. solani development using a whole-tuber assay. Several of them, including Alcaligenes piechaudii, Aquaspirillum autotrophicum, Arcanobacterium haemolyticum, Arthrobacter oxydans, Bacillus mycoides, Kocuria rosea, Streptomyces griseus, and a fungus of the class Zygomycetes displayed an ability to reduce the development of silver scurf on potato tubers at 10, 15, or 24°C. These results can find useful applications toward a biocontrol program of potato silver scurf as postharvest or seed tuber treatment.

scholarly journals Potato Yield and Yield Components as Affected by Positive Selection During Several Generations of Seed Multiplication in Southwestern Uganda

2020 ◽  
Vol 63 (4) ◽  
pp. 507-543 ◽  
Author(s):  
Uta Priegnitz ◽  
Willemien J. M. Lommen ◽  
René A. A. van der Vlugt ◽  
Paul C. Struik
Keyword(s):  
Positive Selection ◽  
Field Trials ◽  
Potato Seed ◽  
Seed Selection ◽  
Potato Tubers ◽  
Yield Increase ◽  
Seed Technology ◽  
Seed Tubers ◽  
The Individual ◽  
Southwestern Uganda

AbstractPotato (Solanum tuberosum L.) is an important crop in Uganda but production is low. There is not a well-functioning official seed system and farmers use potato tubers from a previous harvest as seed. This study investigated how effectively the seed technology positive selection enhanced yield and underlying crop characteristics across multiple seasons, compared to the farmers’ selection method. Positive selection is selecting healthy plants during crop growth for harvesting seed potato tubers to be planted in the next season. Farmers’ selection involves selection of seed tubers from the bulk of the ware potato harvest. Positive selection was compared to farmers’ seed selection for up to three seasons in three field trials in different locations in southwestern Uganda using seed lots from different origins. Across all experiments, seasons and seed lots, yields were higher under positive selection than under farmers’ selection. The average yield increase resulting from positive selection was 12%, but yield increases were variable, ranging from − 5.7% to + 36.9%, and in the individual experiments often not significant. These yield increases were due to higher yields per plant, and mostly higher weights per tuber, whereas the numbers of tubers per plant were not significantly different. Experimentation and yield assessment were hampered by a varying number of plants that could not be harvested because plants had to be rogued from the experimental plots because of bacterial wilt (more frequent under farmers’ selection than under positive selection), plants disappeared from the experimental field and sometimes plants did not emerge. Nevertheless, adoption of positive selection should be encouraged due to a higher production and less virus infection of seed tubers in positive selected plants, resulting in a lower degeneration rate of potato seed tubers.

Determination of optimum tuber planting density in the potato varieties Pentland Squire, Cara, Estima, Maris Piper and King Edward

1992 ◽  
Vol 119 (1) ◽  
pp. 35-44 ◽  
Author(s):  
D. C. E. Wurr ◽  
J. R. Fellows ◽  
E. J. Allen
Keyword(s):  
Complex Analysis ◽  
Seed Tuber ◽  
Tuber Size ◽  
Planting Density ◽  
Potato Seed ◽  
Stem Density ◽  
Seed Tubers ◽  
Net Returns ◽  
Analysis Technique ◽  
The Cost

SummaryThirty-two experiments examining the effects of the weight and within-row spacing of potato seed tubers on graded tuber yields of five varieties were conducted on eight sites from 1980 to 1985. A complex analysis technique was used to combine these data and estimate the optimum tuber planting densities for different ratios of seed cost to small (40–60 mm) and large (60–80 mm) ware value. The same technique could be applied to any other combination of seed cost, ware size and ware value.The optimum tuber planting density decreased with increasing seed-tuber weight. Differences in optimum planting density between varieties were much greater with small (35 g) than with large (105 g) seed tubers and decreased as the cost of seed increased relative to the value of ware. As large ware became worth more than small ware the influence of increasing seed cost on the optimum density was reduced. As the value of large ware increased, net returns increased and the effect of seed cost on net returns was reduced. Mean tuber size decreased with increasing stem density at harvest and at the same stem density was lower in varieties producing more daughter tubers/stem. Changes of mean tuber size (μ) and the spread of yield across size grades (σ) with time were well described by parallel curves in different varieties. It is suggested that in future it may not be necessary to determine optimum tuber planting densities by complex experiments involving several seed-tuber weights and spacings. Instead μ and σ could be estimated from simple experiments and tuber spacings determined by comparison with control varieties.

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.

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