scholarly journals Aggressiveness of Isolates of Phytophthora infestans from the Columbia Basin of Washington and Oregon

1998 ◽  
Vol 88 (3) ◽  
pp. 190-197 ◽  
Author(s):  
Jeffrey S. Miller ◽  
Dennis A. Johnson ◽  
Philip B. Hamm
Keyword(s):  
Phytophthora Infestans ◽  
Lesion Size ◽  
Columbia Basin ◽  
Potato Plants ◽  
Progress Curve ◽  
Expansion Curve ◽  
The Us ◽  
Sporulation Capacity ◽  
Detached Leaflet Assay ◽  
Whole Plants

The aggressiveness of 22 isolates of Phytophthora infestans collected from naturally infected potato plants in the Columbia Basin of Washington and Oregon was determined on detached potato leaflets at 18°C in an incubator. Selected isolates were evaluated on whole plants in a greenhouse. Aggressiveness was measured by using the area under the lesion expansion curve (AULEC), incubation period, latent period, sporulation capacity, and lesion size on detached leaflets and the area under the disease progress curve and sporulation capacity on whole plants. The detached-leaflet assay was useful in that a large number of isolates were tested, several components of aggressiveness were studied, and significant differences were found among isolates. Significant variation for components of aggressiveness was found within and among isolates classified according to genotype. Significant interactions among isolates and cultivars were found for some components of aggressiveness, so results were pooled according to cultivar. On average, US-8 and US-11 isolates had higher AULEC scores, indicating aggressiveness higher than that of US-7, US-6, and US-1 genotypes. One US-8 genotype isolate had a higher standardized sporulation capacity than isolates of the other genotypes. US-6 genotype isolates were the least aggressive group, as indicated by low AULEC, sporulation capacity, and lesion size values. The replacement of the US-1 genotype by the US-8 genotype in the Columbia Basin may be partially explained by the increased aggressiveness of US-8 isolates. Additionally, potato growers may need to shorten intervals between fungicide applications and begin applications earlier.

scholarly journals Classifying the Relative Host Reaction in Potato Cultivars and Breeding Lines to the US-8 Strain of Phytophthora infestans in Minnesota

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 983-990 ◽  
Author(s):  
J. C. Jenkins ◽  
R. K. Jones
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Rank Correlation ◽  
The United States ◽  
Spearman Rank Correlation ◽  
Breeding Lines ◽  
Spearman Rank ◽  
Progress Curve ◽  
Tuber Blight ◽  
The Us

A total of 32 commercial cultivars grown in the United States and 15 potato breeding lines and non-U.S. cultivars were evaluated at Rosemount, MN for their reaction to the US-8 strain of Phytophthora infestans. Commercial red-, russet-, and white-skinned cultivars tested in the commercial cultivar trial (COMC) in 1996 and 1997 were susceptible (S) to moderately susceptible (MS) to this organism, except for Elba, which ranked as moderately resistant (MR). Yellow-fleshed cvs. Hertha, Santé, and Agria were screened in the late blight nursery (LB1) in 1997 and 1998 and classified as S to MS while Island Sunshine, Brador, and Aziza were classified as MR. The Scottish breeding line G6582-3 and U.S. breeding lines A90586-11, AWN86514-2, AWN85624-5, B0692-4, B0718-3, and B0767-2 were classified as resistant (R). Comparison among entries was based on the area under the disease progress curve (AUDPC). Spearman rank correlation for AUDPC in the 1996 and 1997 COMC trials at 14 to 18 days after inoculation (r = 0.65, P < 0.01) was greater than any other interval tested. The Spearman rank correlation for AUDPC in the 1997 and 1998 LB1 trials at 14 to 18 days after inoculation was r = 0.87, P < 0.01 and increased only slightly in successive assessment dates, suggesting that, in Minnesota, effective evaluation of the foliar infection of late blight can occur at 18 days after inoculation or later. The average tuber blight incidence for the COMC trials at harvest was 10.0% in 1996 and 9.7% in 1997. The average tuber blight incidence for the LB1 trials at harvest was 4.3% in 1997 and 14.6% in 1998. Pearson correlations between tuber blight incidence and foliar disease for the COMC trials was very low; however, for the LBl trials, it was significant in both 1997 (r = 0.53, P < 0.01) and 1998 (r = 0.53, P < 0.01). Asymptomatic tubers harvested from the COMC trials developed additional tuber blight when stored 28 days at ambient temperatures and still more when stored for another 5 months at 5°C. Surviving tubers of nine entries were planted in field trials during 1997 and 1998 to determine if plants that develop from tubers exposed to P. infestans could manifest late blight in the subsequent season. Late blight failed to develop throughout the trials in either year.

scholarly journals Implications of Sexual Reproduction for Phytophthora infestans in the United States: Generation of an Aggressive Lineage

Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 731-735 ◽  
Author(s):  
P. D. Gavino ◽  
C. D. Smart ◽  
R. W. Sandrock ◽  
J. S. Miller ◽  
P. B. Hamm ◽  
...  
Keyword(s):  
United States ◽  
Phytophthora Infestans ◽  
The United States ◽  
Mitochondrial Haplotype ◽  
Columbia Basin ◽  
Clonal Lineage ◽  
Large Area ◽  
The Us ◽  
Sexual Progeny

Phytophthora infestans isolates (n = 26) collected in the Columbia Basin of Oregon and Washington in 1993, which had been characterized previously for mating type, metalaxyl sensitivity, and alleles at the glucose-6-phosphate isomerase locus, were analyzed for nuclear restriction fragment length polymorphism (RFLP) bands detected by probe RG57 and mitochondrial haplotype. Analyses involving the larger set of markers indicated that this group of isolates satisfied expectations of a sexual progeny: they contained much greater genetic diversity than has been reported for most other epidemic populations of P. infestans in the United States and Canada (16 unique multilocus genotypes); both mating types were present in proximity; all possible combinations of alleles occurred at many pairs of polymorphic loci; and two distinct mitochondrial haplotypes were distributed among the isolates. An in vitro laboratory cross involving the putative parents (US-6 and US-7) as parental strains produced progeny with the same general characteristics as the field isolates. Among the field progeny were two genotypes, US-11 and US-16, that had been described previously but from subsequent and largely clonal collections. Isolates obtained from tomatoes (n = 40) and potatoes (n = 7) in 24 counties in California in 1998 were analyzed as described above, and all except one US-8 isolate from potatoes were of the US-11 clonal lineage, consistent with the hypothesis that the US-11 lineage is an especially fit clonal lineage that has survived over time and can dominate pathogen populations over a large area. We conclude that the 1993 Columbia Basin collection represents a sexual progeny that generated the US-11 lineage, and that this lineage is particularly fit when tomatoes are part of the agroecosystem.

scholarly journals Characterization of the Phytophthora infestans Population in the Columbia Basin of Oregon and Washington from 1992 to 1995

1997 ◽  
Vol 87 (6) ◽  
pp. 656-660 ◽  
Author(s):  
Jeffrey S. Miller ◽  
Philip B. Hamm ◽  
Dennis A. Johnson
Keyword(s):  
Phytophthora Infestans ◽  
Growing Season ◽  
Resistant Isolate ◽  
Multilocus Genotype ◽  
Columbia Basin ◽  
The Us ◽  
Metalaxyl Sensitivity ◽  
Genotype A

Isolates of Phytophthora infestans collected from 1992 to 1995 from potato fields in the Columbia Basin of Oregon and Washington were analyzed for compatibility type, metalaxyl sensitivity, and glucose-6-phosphate isomerase (Gpi) genotype. In 1992, 30 of 31 isolates were of the US-1 multilocus genotype. A single metalaxyl-resistant isolate of the US-6 (A1 Gpi 86/100) genotype was found near the end of the growing season. In 1993, only 2 of the 59 isolates collected were A1 isolates with Gpi 86/100. Ten isolates were of the A2 compatibility type, seven with Gpi 100/111, two with Gpi 100/100, and one was undetermined. The remaining isolates were metalaxyl-resistant A1 compatibility types with either Gpi 100/100 or 100/111. The first A2 isolates in the Columbia Basin were found in 1993. In 1994, 10 of 18 isolates were of the US-1 genotype. The remaining isolates were US-6 and US-8 genotypes. In 1995, 97% of 268 isolates tested were of the US-8 genotype. Five isolates were A2 compatibility type with Gpi 100/122. One A2, metalaxyl-resistant isolate was Gpi 100/100/111, and two A1 isolates were Gpi 100/111/122. The population of P. infestans quickly changed between 1992 and 1995, from a population comprised almost exclusively of the US-1 genotype to a population represented by new or recombinant genotypes.

scholarly journals Pathogenicity and Aggressiveness of Three Alternaria spp. on Potato Foliage in the U.S. Northwest

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 797-801 ◽  
Author(s):  
Lydia S. Tymon ◽  
Thomas F. Cummings ◽  
Dennis A. Johnson
Keyword(s):  
Alternaria Solani ◽  
Russet Burbank ◽  
Brown Spot ◽  
Columbia Basin ◽  
Russet Norkotah ◽  
Expansion Curve ◽  
Detached Leaves ◽  
Potato Foliage ◽  
Whole Plants ◽  
Umatilla Russet

Alternaria spp. were collected from potato foliage showing symptoms of early blight and brown spot in the Columbia Basin, WA and Bonners Ferry and Rupert, ID between 2009 and 2011. The aggressiveness of three Alternaria spp. on potato was quantified on nonwounded and wounded detached leaves of ‘Russet Norkotah’ potato; wounded detached leaves of ‘Alturas’, ‘Ranger Russet’, ‘Russet Burbank’, and ‘Umatilla Russet’; and whole plants of Russet Norkotah. Mean infection frequencies (MIF) and area under the lesion expansion curve (AULEC) were significantly greater for Alternaria solani (P = 0.0072 and 0.0002, respectively) than for A. arborescens or A. arbusti on nonwounded leaves. Wounding of tissue significantly increased MIF and AULEC for A. arbusti (P = 0.008 and 0.0047, respectively) and AULEC for A. arborescens (P = 0.01) relative to nonwounded tissue. AULEC did not differ significantly among the three Alternaria spp. when inoculated onto wounded foliage of whole plants (P = 0.34); the AULEC of whole plants was positively and significantly correlated with AULEC on detached leaves (P = 0.03). Umatilla Russet was the most susceptible and Russet Burbank was the least susceptible based on MIF and AULEC for all three pathogen species. Results indicate that A. solani was the more aggressive pathogen of potato in the Columbia Basin, because both A. arborescens and A. arbusti require wounds and A. arbusti lesions do not expand significantly in comparison with A. solani or A. arborescens following inoculation.

scholarly journals Effects of Temperature on Events in the Infection Cycle of Two Clonal Lineages of Phytophthora infestans Causing Late Blight on Tomato and Potato in Brazil

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 459-466 ◽  
Author(s):  
José Marcelo N. Maziero ◽  
Luiz A. Maffia ◽  
Eduardo S. G. Mizubuti
Keyword(s):  
Phytophthora Infestans ◽  
Management Strategies ◽  
Quantitative Information ◽  
Leaf Wetness ◽  
Infection Cycle ◽  
Lesion Area ◽  
Tomato Plants ◽  
Potato Plants ◽  
Effects Of Temperature ◽  
Whole Plants

In Brazil, US-1 and BR-1 clonal lineages of Phytophthora infestans are widely distributed throughout the major growing areas of tomato and potato, respectively. Quantitative information regarding the effects of temperature (10, 15, 22, and 27°C) on direct and indirect sporangia germination, incubation period (IP), latent period (LP), lesion area (LA), and sporulation (SP), as well as combined temperature and leaf wetness duration periods (6, 12, 18, and 24 h) on the number of lesions (NL) was obtained under controlled conditions on either detached leaflets or whole plants. The percentage of indirect germination was higher for BR-1 isolates than for US-1. The percentage of direct germination was higher for US-1 than for BR-1. The shortest IP and LP were recorded at 22°C for both lineages: 69.3 h and 93.3 h for US-1 isolates on detached tomato leaflets, and 44.0 h and 68 h for BR-1 isolates on detached potato leaflets, respectively. US-1 isolates did not sporulate at 10°C, and BR-1 isolates did not sporulate at 27°C. Isolates of both lineages induced the largest LA at 22°C. The NL was highest at 15°C for US-1 isolates on whole tomato plants, and at 10°C for BR-1 isolates on whole potato plants. The differential effects of temperature on US-1 and BR-1 suggest that current decision support systems initially developed for controlling US-1 in Brazil may now be inaccurate for controlling BR-1, and management strategies should be properly validated before being used.

scholarly journals Biological control of strawberry crown rot, root rot and grey mould by the beneficial fungus Aureobasidium pullulans

BioControl ◽  
2021 ◽  
Author(s):  
Mudassir Iqbal ◽  
Maha Jamshaid ◽  
Muhammad Awais Zahid ◽  
Erik Andreasson ◽  
Ramesh R. Vetukuri ◽  
...  
Keyword(s):  
Root Rot ◽  
Fungal Pathogens ◽  
Aureobasidium Pullulans ◽  
Grey Mould ◽  
Lesion Size ◽  
Plant Diseases ◽  
Crown Rot ◽  
Whole Plants

AbstractUtilization of biocontrol agents is a sustainable approach to reduce plant diseases caused by fungal pathogens. In the present study, we tested the effect of the candidate biocontrol fungus Aureobasidium pullulans (De Bary) G. Armaud on strawberry under in vitro and in vivo conditions to control crown rot, root rot and grey mould caused by Phytophthora cactorum (Lebert and Cohn) and Botrytis cinerea Pers, respectively. A dual plate confrontation assay showed that mycelial growth of P. cactorum and B. cinerea was reduced by 33–48% when challenged by A. pullulans as compared with control treatments. Likewise, detached leaf and fruit assays showed that A. pullulans significantly reduced necrotic lesion size on leaves and disease severity on fruits caused by P. cactorum and B. cinerea. In addition, greenhouse experiments with whole plants revealed enhanced biocontrol efficacy against root rot and grey mould when treated with A. pullulans either in combination with the pathogen or pre-treated with A. pullulans followed by inoculation of the pathogens. Our results demonstrate that A. pullulans is an effective biocontrol agent to control strawberry diseases caused by fungal pathogens and can be an effective alternative to chemical-based fungicides.

scholarly journals Fungicide Sensitivity of U.S. Genotypes of Phytophthora infestans to Six Oomycete-Targeted Compounds

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 659-666 ◽  
Author(s):  
Amanda Saville ◽  
Kim Graham ◽  
Niklaus J. Grünwald ◽  
Kevin Myers ◽  
William E. Fry ◽  
...  
Keyword(s):  
United States ◽  
Phytophthora Infestans ◽  
The United States ◽  
Effective Concentration ◽  
Response Curves ◽  
Baseline Sensitivity ◽  
Fungicide Sensitivity ◽  
The Past ◽  
The Us

Phytophthora infestans causes potato late blight, an important and costly disease of potato and tomato crops. Seven clonal lineages of P. infestans identified recently in the United States were tested for baseline sensitivity to six oomycete-targeted fungicides. A subset of the dominant lineages (n = 45) collected between 2004 and 2012 was tested in vitro on media amended with a range of concentrations of either azoxystrobin, cyazofamid, cymoxanil, fluopicolide, mandipropamid, or mefenoxam. Dose-response curves and values for the effective concentration at which 50% of growth was suppressed were calculated for each isolate. The US-8 and US-11 clonal lineages were insensitive to mefenoxam while the US-20, US-21, US-22, US-23, and US-24 clonal lineages were sensitive to mefenoxam. Insensitivity to azoxystrobin, cyazofamid, cymoxanil, fluopicolide, or mandipropamid was not detected within any lineage. Thus, current U.S. populations of P. infestans remained sensitive to mefenoxam during the displacement of the US-22 lineage by US-23 over the past 5 years.

Chemotype and aggressiveness evaluation of Fusarium graminearum and Fusarium culmorum isolates from wheat fields in Wisconsin

Plant Disease ◽  
2021 ◽  
Author(s):  
Brian Mueller ◽  
Carol Groves ◽  
Damon L. Smith
Keyword(s):  
Growth Rate ◽  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Fusarium Culmorum ◽  
Head Blight ◽  
Growing Seasons ◽  
Progress Curve ◽  
Sporulation Capacity ◽  
Derivatives Of

Fusarium graminearum commonly causes Fusarium head blight (FHB) on wheat, barley, rice, and oats. Fusarium graminearum produces nivalenol and deoxynivalenol (DON) and forms derivatives of DON based on its acetylation sites. The fungus is profiled into chemotypes based on DON derivative chemotypes (3 acetyldeoxynivalenol (3ADON) chemotype; 15 acetyldeoxynivalenol (15ADON) chemotype) and/or the nivalenol (NIV) chemotype. The current study assessed the Fusarium population found on wheat and the chemotype profile of the isolates collected from 2016 and 2017 in Wisconsin. Fusarium graminearum was isolated from all locations sampled in both 2016 and 2017. Fusarium culmorum was isolated only from Door County in 2016. Over both growing seasons, 91% of isolates were identified as the 15ADON chemotype while 9% of isolates were identified as the 3ADON chemotype. Aggressiveness was quantified by area under disease progress curve (AUDPC). The isolates with the highest AUDPC values were from the highest wheat producing cropping districts in the state. Deoxynivalenol production in grain and sporulation and growth rate in vitro were compared to aggressiveness in the greenhouse. Our results showed that 3ADON isolates in Wisconsin were among the highest in sporulation capacity, growth rate, and DON production in grain. However, there were no significant differences in aggressiveness between the 3ADON and 15ADON isolates. The results of this research detail the baseline frequency and distribution of 3ADON and 15ADON chemotypes observed in Wisconsin. Chemotype distributions within populations of F. graminearum in Wisconsin should continue to be monitored in the future.

scholarly journals Isolate-Dependent Inheritance of Resistance Against Pseudoperonospora cubensis in Cucumber

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1086 ◽  
Author(s):  
Tomer Chen ◽  
Daniel Katz ◽  
Yariv Ben Naim ◽  
Rivka Hammer ◽  
Bat Hen Ben Daniel ◽  
...  
Keyword(s):  
Segregation Ratio ◽  
Lesion Size ◽  
Pseudoperonospora Cubensis ◽  
Plant Introductions ◽  
Growing Seasons ◽  
Multiple Phenotypes ◽  
Progress Curve ◽  
Growth Chambers ◽  
Wild Accessions ◽  
Moderately Resistant

Six wild accessions of Cucumis sativum were evaluated for resistance against each of the 23 isolates of the downy mildew oomycete Pseudoperonospora cubensis. The isolates originated from Israel, Europe, USA, and Asia. C. sativum PI 197088 (India) and PI 330628 (Pakistan) exhibited the highest level of resistance against multiple isolates of P. cubensis. Resistance was manifested as reduced lesion number, lesion size, sporangiophores and sporangia per lesion and enhanced encasement of haustoria with callose and intensive accumulation of lignin in lesions of both Plant Introductions (PIs) compared to the susceptible C. sativum SMR-18. In the field, much smaller AUDPC (Area Under Disease Progress Curve) values were recorded in PI 197088 or PI 330628 as compared to SMR-18. Each PI was crossed with SMR-18 and offspring progeny plants were exposed to inoculation with each of several isolates of P. cubensis in growth chambers and the field during six growing seasons. F1 plants showed partial resistance. F2 plants showed multiple phenotypes ranging from highly susceptible (S) to highly resistant (R, no symptoms) including moderately resistant (MR) phenotypes. The segregation ratio between phenotypes in growth chambers ranged from 3:1 to 1:15, depending on the isolate used for inoculation, suggesting that the number of genes, dominant, partially dominant, or recessive are responsible for resistance. In the field, the segregation ratio of 1:15, 1:14:1, or 1:9:6 was observed. F2 progeny plants of the cross between the two resistant PI’s were resistant, except for a few plants that were partially susceptible, suggesting that some of the resistance genes in PI 197088 and PI 330328 are not allelic.

scholarly journals Ethylicin Prevents Potato Late Blight by Disrupting Protein Biosynthesis of Phytophthora infestans

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 299
Author(s):  
Shumin Zhang ◽  
Meiquan Zhang ◽  
A. Rehman Khalid ◽  
Linxuan Li ◽  
Yang Chen ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Protein Biosynthesis ◽  
Potato Late Blight ◽  
Inhibitory Effect ◽  
Integrated Analysis ◽  
Irish Famine ◽  
Great Irish Famine ◽  
Ribosomal Function ◽  
Sporulation Capacity

Phytophthora infestans, the causal agent of potato late blight, triggered the devastating Great Irish Famine that lasted from 1845 to 1852. Today, it is still the greatest threat to the potato yield. Ethylicin is a broad-spectrum biomimetic-fungicide. However, its application in the control of Phytophthora infestans is still unknown. In this study, we investigated the effects of ethylicin on Phytophthora infestans. We found that ethylicin inhibited the mycelial growth, sporulation capacity, spore germination and virulence of Phytophthora infestans. Furthermore, the integrated analysis of proteomics and metabolomics indicates that ethylicin may inhibit peptide or protein biosynthesis by suppressing both the ribosomal function and amino acid metabolism, causing an inhibitory effect on Phytophthora infestans. These observations indicate that ethylicin may be an anti-oomycete agent that can be used to control Phytophthora infestans.

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