Effect of strobilurin fungicides on control of early blight (Alternaria solani) and yield of potatoes grown under two N fertility regimes

William MacDonald; Rick D. Peters; Robert H. Coffin; Christian Lacroix

doi:10.7202/016397ar

Effect of strobilurin fungicides on control of early blight (Alternaria solani) and yield of potatoes grown under two N fertility regimes

Phytoprotection ◽

10.7202/016397ar ◽

2007 ◽

Vol 88 (1) ◽

pp. 9-15 ◽

Cited By ~ 8

Author(s):

William MacDonald ◽

Rick D. Peters ◽

Robert H. Coffin ◽

Christian Lacroix

Keyword(s):

Prince Edward Island ◽

Early Blight ◽

Tuber Yield ◽

Alternaria Solani ◽

Field Trials ◽

Potato Yield ◽

Russet Burbank ◽

Strobilurin Fungicides ◽

N Fertility

Early blight, caused by Alternaria solani, is a ubiquitous disease that can reduce potato yield. Adequate crop fertility and appropriate fungicide applications usually suppress the development of this disease. Field trials were established in Prince Edward Island to determine whether strobilurin analogs, namely azoxystrobin and pyraclostrobin, could suppress early blight of potatoes (cvs. Shepody and Russet Burbank) grown under two nitrogen (N) fertility regimes (high or low N). Azoxystrobin and pyraclostrobin were linked to significantly higher total tuber yield for Russet Burbank in 2003 and Shepody in 2004 when compared to plots receiving no strobilurin fungicides. No significant differences in total tuber yield based on N fertility were observed, although the high N rate decreased disease in Russet Burbank control plots in 2004. Due to an absence of early blight in 2003, the increase in Russet Burbank yield may be attributed to the physiological and developmental alterations brought about by strobilurin products in treated plants. In 2004, early blight was severe in inoculated control plots, but it was significantly suppressed in plots having received azoxystrobin or pyraclostrobin, regardless of the cultivar type or fertility regime. Therefore, to prevent unnecessary N inputs, growers need to supply only the necessary N amount to optimize tuber yields and manage early blight with fungicides.

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Effect of fungicide use strategies on the control of early blight (Alternaria solani) and potato yield

Australasian Plant Pathology ◽

10.1071/ap09090 ◽

2010 ◽

Vol 39 (4) ◽

pp. 368 ◽

Cited By ~ 44

Author(s):

Andrew Horsfield ◽

Trevor Wicks ◽

Kent Davies ◽

Doug Wilson ◽

Scott Paton

Keyword(s):

Early Blight ◽

Alternaria Solani ◽

Potato Yield

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Resistance to Phytophthora infestans Clonal Lineage US-23 in Potato Cultivars and Its Relationship with Early Blight Resistance and Tuber Yield

Plant Disease ◽

10.1094/pdis-03-21-0594-re ◽

2021 ◽

Author(s):

Weiya Xue ◽

Kathleen G. Haynes ◽

Xinshun Qu

Keyword(s):

Late Blight ◽

Phytophthora Infestans ◽

Early Blight ◽

Tuber Yield ◽

Late Blight Resistance ◽

Field Trials ◽

Potato Cultivars ◽

Blight Resistance ◽

Clonal Lineage ◽

Progress Curve

Resistance to late blight, caused by Phytophthora infestans clonal lineage US-23, in 217 old and modern potato cultivars was evaluated in field trials in 2016 and 2017 in Pennsylvania. Significant differences in resistance were found among these cultivars (P < 0.0001). Significant interaction between cultivars and environments was found (P < 0.0001). The values of relative area under the disease progress curve ranged from 0 to 0.5841 in 2016 and from 0 to 0.5469 in 2017. Broad-sense heritability of late blight resistance was estimated to be 0.91 with a 95% confidence interval of 0.88 to 0.93. Cluster analysis classified the cultivars into 5 groups: resistant, moderately resistant, intermediate, moderately susceptible, and susceptible. Thirty cultivars showing resistance and 32 cultivars showing moderate resistance were identified. The 217 cultivars were also evaluated for foliar maturity, tuber yield and resistance to early blight, caused by Alternaria solani. A few cultivars with late blight resistance independent of late maturity were found. Late blight resistance and early blight resistance were positively correlated, and 17 cultivars possessed resistance to both diseases. Yield tradeoff associated with late blight resistance was not observed among the cultivars in the absence of disease pressure.

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Occurrence of sdh Mutations in German Alternaria solani Isolates and Potential Impact on Boscalid Sensitivity In Vitro, in the Greenhouse, and in the Field

Plant Disease ◽

10.1094/pdis-03-19-0617-re ◽

2019 ◽

Vol 103 (12) ◽

pp. 3065-3071 ◽

Cited By ~ 1

Author(s):

Nicole Metz ◽

Birgit Adolf ◽

Nicole Chaluppa ◽

Ralph Hückelhoven ◽

Hans Hausladen

Keyword(s):

Succinate Dehydrogenase ◽

Early Blight ◽

Solanum Tuberosum L ◽

Point Mutations ◽

Alternaria Solani ◽

Field Trials ◽

Sensitivity Testing ◽

Development Of Resistance

The fungus Alternaria solani is the main pathogen causing early blight on potatoes (Solanum tuberosum L.). An increase in the development of resistance to the succinate dehydrogenase inhibitor (SDHI) boscalid, one of the main active ingredients for the control of early blight, has been reported. For this study, monitoring data from Germany were collected between 2013 and 2016 and an increase in the occurrence of A. solani succinate dehydrogenase (SDH) mutant isolates was observed. In addition to the known point mutations in sdh complex II, a new mutation in subunit C was found in German isolates (SdhC-H134Q). SDHI fungicide sensitivity testing was performed in the laboratory, greenhouse, and field. Reduced boscalid sensitivity was shown for mutant isolates (SdhB-H278Y and SdhC-H134R) both in vitro and in vivo. In addition, field trials with artificial inoculation were performed in 2016 and 2017. In both years, fungicide efficacy was significantly reduced after mutant inoculation compared with wild-type inoculation.

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QTL Mapping for Resistance to Early Blight in a Tetraploid Potato Population

Agronomy ◽

10.3390/agronomy10050728 ◽

2020 ◽

Vol 10 (5) ◽

pp. 728

Author(s):

Firuz Odilbekov ◽

Catja Selga ◽

Rodomiro Ortiz ◽

Aakash Chawade ◽

Erland Liljeroth

Keyword(s):

Disease Resistance ◽

Linkage Mapping ◽

Early Blight ◽

Tuber Yield ◽

Alternaria Solani ◽

Field Evaluation ◽

Blight Resistance ◽

Yield Losses ◽

Tetraploid Potato ◽

Resistance Assessment

Early blight of potato, caused by Alternaria solani, is an economically important foliar disease in most potato-growing regions. Growing cultivars with higher levels of resistance to early blight can reduce tuber yield losses and the need for fungicide applications. In this research, a bi-parental tetraploid potato population, segregating for resistance to early blight in leaves and tubers, was characterized to identify novel quantitative trait loci (QTL) associated with foliar and tuber early blight resistance. Assessment of the disease resistance in the foliage was performed by field evaluation and in tuber under controlled conditions. Results from this study revealed significant differences (P < 0.001) in resistance to A. solani among potato clones both in the leaves and in tubers. There was no statistically significant correlation (r = 0.06, P = 0.35) between the resistance scores from leaves and tubers. Several clones exhibited; however, high levels of resistance both in leaves and tubers and are; thus, promising candidates for breeding for early blight resistance. Linkage mapping revealed several QTL for early blight affecting both foliage and tubers. QTL associated with disease resistance in the tuber were found on chromosomes 1, 2, 3, 4, 8, 11 and 12. QTL associated with disease resistance in foliage were also examined for independence from defoliation, and independent QTL were; thus, found on chromosomes 5 and 11.

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QUACKGRASS COMPETITION EFFECT ON POTATO YIELD

Canadian Journal of Plant Science ◽

10.4141/cjps86-027 ◽

1986 ◽

Vol 66 (1) ◽

pp. 185-187 ◽

Cited By ~ 11

Author(s):

J. A. IVANY

Keyword(s):

Solanum Tuberosum ◽

Tuber Yield ◽

Solanum Tuberosum L ◽

Total Yield ◽

Potato Yield ◽

Russet Burbank ◽

Competition Effect ◽

Marketable Tuber ◽

Agropyron Repens

The effect of different periods of quackgrass (Agropyron repens L. Beauv.) competition after crop emergence was studied for potato (Solanum tuberosum L. ’Russet Burbank’). Delaying quackgrass removal for 2 wk after crop emergence reduced small-sized tuber yield, marketable tuber yield and total yield by 6%, 27% and 21%, respectively, averaged over 4 yr. Successively longer delays in quackgrass removal showed progressively greater reductions in yield.Key words: Quackgrass, potato, competition

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Impact of SDH Mutations in Alternaria solani on Recently Developed SDHI Fungicides Adepidyn and Solatenol

Plant Disease ◽

10.1094/pdis-12-20-2718-re ◽

2021 ◽

Author(s):

Sarah Rodriguez ◽

Rhodesia Celoy ◽

Ipsita Mallik ◽

Julie Sherman Pasche ◽

Neil C Gudmestad

Keyword(s):

Early Blight ◽

Field Experiments ◽

Alternaria Solani ◽

Potato Production ◽

Field Trials ◽

Intrinsic Activity ◽

In Vitro Assays ◽

Commercial Application ◽

Quinone Outside Inhibitor

Early blight, caused by Alternaria solani, is observed annually in all midwestern potato production areas. The use of foliar fungicides remains a primary management strategy. However, A. solani has developed reduced-sensitivity or resistance to many single-site fungicides such as quinone outside inhibitor (QoI, FRAC group 11), succinate dehydrogenase inhibitor (SDHI, FRAC group 7), demethylation inhibitors (DMI, FRAC group 3), and anilinopyrimidine (AP, FRAC group 9) fungicides. Boscalid, fluopyram, solatenol, and adepidyn are EPA-registered SDHI fungicides used commercially on a variety of crops, including potato. Five SDH mutations have been characterized previously in A. solani that affect the efficacy of boscalid while only one of these mutations has been demonstrated to negatively affect fluopyram efficacy. Conidial germination assays were used to determine if a shift in sensitivity has occurred in these SDHI fungicides. Alternaria solani isolates collected prior to the commercial application of SDHI fungicides (baseline) and were compared to recently collected isolates (non-baseline). Greenhouse evaluations were conducted also to evaluate the efficacy of boscalid, fluopyram, solatenol, and adepidyn on A. solani isolates possessing individual SDH mutations. Additionally, field trials were conducted to determine the effects application of these SDHI fungicides on the frequency of SDH mutations. Fluopyram, solatenol, and adepidyn had high intrinsic activity against A. solani when compared to boscalid, based on in vitro assays. The application of adepidyn and solatenol resulted in greater early blight control than the application of boscalid and fluopyram in greenhouse experiments. Molecular characterization of A. solani isolates collected from the field trials determined that the frequency of the H134R-mutation can increase in response to more recently developed SDHI fungicides. In contrast, the H278R/Y- and H133R-mutations decreased to the point of being nearly absent in these field experiments.

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Diversity and Virulence of Alternaria spp. Causing Potato Early Blight and Brown Spot in Wisconsin

Phytopathology ◽

10.1094/phyto-06-18-0181-r ◽

2019 ◽

Vol 109 (3) ◽

pp. 436-445 ◽

Cited By ~ 7

Author(s):

Shunping Ding ◽

Kiana Meinholz ◽

Kenneth Cleveland ◽

Stephen A. Jordan ◽

Amanda J. Gevens

Keyword(s):

Early Blight ◽

Elongation Factor ◽

Alternaria Solani ◽

Potato Production ◽

Russet Burbank ◽

Brown Spot ◽

Breeding Line ◽

Quinone Outside Inhibitor ◽

Significant Difference ◽

Promising Source

Early blight, caused by Alternaria solani, along with brown spot, caused by A. alternata, have the potential to reduce quality and yield in potato production globally. Prior to this study, the incidence, disease impact, and fungicide resistance attributes of A. alternata in Wisconsin were poorly understood. Potato pathogens were isolated from foliar lesions at three commercial locations in Wisconsin in 2012 and 2017 and were initially morphologically identified as A. solani (n = 33) and A. alternata (n = 40). Identifications were further corroborated with the phylogenetic analysis of the internal transcribed spacer (ITS), translation elongation factor 1 (TEF1), gapdh, Alt a 1, and OPA10-2. A multigene phylogeny of ITS, TEF1, gapdh, and Alt a 1 showed five genotypes of A. alternata and one single genotype of A. solani. We demonstrated that the A. alternata isolates were virulent on potato cultivars Russet Burbank (P < 0.013) and Atlantic (P < 0.0073), though they caused less disease than A. solani (P < 0.0001 and P < 0.0001, respectively). A. alternata caused little disease on the breeding line 24-24-12 (P = 0.9929), and A. solani caused fewer disease symptoms on 24-24-12 than on Russet Burbank (P < 0.0001) or Atlantic (P < 0.0001). Breeding line 24-24-12 may be a promising source of potential resistance for the two diseases. There was no significant difference in virulence of different A. alternata genotypes, and no significant difference in virulence or genotype clustering among isolates from the three locations. Isolates of A. alternata that induced chlorosis caused larger lesion areas than isolates that did not in Russet Burbank (P < 0.0001), Atlantic (P < 0.0001), and 24-24-12 (P = 0.0365). There was no significant difference in virulence between quinone outside inhibitor (QoI)-sensitive and QoI-resistant isolates of A. alternata. This study enhanced our understanding of potato early blight and brown spot in Wisconsin, and suggested that A. alternata in addition to A. solani should be carefully monitored and possibly uniquely managed in order to achieve overall disease control.

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Rapid emergence of boscalid resistance in Swedish populations of Alternaria solani revealed by a combination of field and laboratory experiments

European Journal of Plant Pathology ◽

10.1007/s10658-021-02403-8 ◽

2021 ◽

Author(s):

Hadis Mostafanezhad ◽

Eva Edin ◽

Laura J. Grenville-Briggs ◽

Åsa Lankinen ◽

Erland Liljeroth

Keyword(s):

Early Blight ◽

Current Knowledge ◽

Low Frequency ◽

High Sensitivity ◽

Alternaria Solani ◽

Field Studies ◽

Field Trials ◽

Gene Encoding ◽

Swedish Population

Abstract Early blight, caused by Alternaria solani, is a common potato disease worldwide. Reduced field efficacy of the fungicide boscalid against this disease has been reported in several countries. Boscalid resistance has been mostly studied with in-vitro and/or greenhouse experiments. Field studies validating this phenomenon are largely missing. Here, for the first time in Scandinavia, we validated boscalid resistance in a Swedish population of A. solani both in the field and in the laboratory. Field trials between 2014 and 2017 in Nymö showed significant efficacy reduction by year. The target regions of the A. solani genes encoding the succinate dehydrogenase subunits (Sdh) B, C and D of samples collected from Nymö, and additional fields in south-eastern and central Sweden, were analysed for substitutions associated with loss of boscalid sensitivity. In 2014, the SdhC-H134R mutation was found at several sites at a low frequency, while, in 2017, the majority of the samples had either the SdhB-H278Y or the SdhC-H134R substitution. No mutations were detected in the gene encoding the SdhD subunit. Spore germination tests showed a high sensitivity (EC50 < 1 μg mL−1) of isolates lacking the substitutions. This was supported by a significant decrease in their radial growth rate, from 0.1 to 10 μg mL−1 boscalid. However, the mutated isolates had EC50 > 100 μg mL−1 and their growth rates hardly decreased at concentrations above 1–10 μg mL−1. These results add to the current knowledge of fungicide resistance development in field and indicate that early blight management in southeast Sweden should no longer rely on boscalid.

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In-Furrow Applications of Metalaxyl and Phosphite for Control of Pink Rot (Phytophthora erythroseptica) of Potato in New Brunswick, Canada

Plant Disease ◽

10.1094/pdis-91-10-1305 ◽

2007 ◽

Vol 91 (10) ◽

pp. 1305-1309 ◽

Cited By ~ 12

Author(s):

Khalil I. Al-Mughrabi ◽

Rick D. Peters ◽

H. W. (Bud) Platt ◽

Gilles Moreau ◽

Appanna Vikram ◽

...

Keyword(s):

New Brunswick ◽

Disease Incidence ◽

Field Trials ◽

Russet Burbank ◽

Viable Option ◽

Potato Plants ◽

Pink Rot ◽

Phytophthora Erythroseptica ◽

Sensitive Isolate ◽

The Mean

The efficacy of metalaxyl-m (Ridomil Gold 480EC) and phosphite (Phostrol) applied at planting in-furrow against pink rot (Phytophthora erythroseptica) of potato (Solanum tuberosum) ‘Shepody’ and ‘Russet Burbank’ was evaluated in field trials conducted in 2005 and 2006 in Florenceville, New Brunswick, Canada. Inoculum made from a metalaxyl-m-sensitive isolate of P. erythroseptica from New Brunswick was applied either in-furrow as a vermiculite slurry at planting or as a zoospore drench in soils adjacent to potato plants in late August. After harvest, the number and weight of tubers showing pink rot symptoms were assessed and expressed as percentages of the total tuber number and total weight of tubers. Metalaxyl-m applied in-furrow was significantly more effective against pink rot than phosphite. The mean percentage of diseased tubers as a percentage of total tuber weight was 1.5% (2005) and 1.2% (2006) for metalaxyl-m-treated plots and 9.6% (2005) and 2.8% (2006) for phosphite-treated plots, a percentage similar to that obtained in inoculated control plots with no fungicide treatment. The mean percentage of diseased tubers expressed as a percentage of the total number of tubers was 1.7% (2005) and 1.3% (2006) for metalaxyl-m-treated plots and 10.1% (2005) and 3.1% (2006) for phosphite-treated plots. Disease incidence was significantly higher using the late-season inoculation technique (respective means in 2005 and 2006 were 9.9 and 3.8% diseased tubers, by weight, and 10.6 and 3.9%, by number) than with the in-furrow inoculation method (respective means in 2005 and 2006 were 3.3 and 0.7% by weight, and 3.7 and 1.3%, by number). The potato cv. Shepody was significantly more susceptible to pink rot (9.9 and 3.3% diseased tubers, by weight, in 2005 and 2006, respectively, and 10.6 and 3.9%, by number) than Russet Burbank (respective means in 2005 and 2006 were 3.4,% and 1.2%, by weight, and 3.7,% and 1.2%, by number). Our findings indicate that metalaxyl applied in-furrow at planting is a viable option for control of pink rot caused by metalaxyl-sensitive strains of P. erythroseptica, whereas phosphite was ineffective.

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