scholarly journals Roles of Infected Seed Tubers and Soilborne Inoculum on Verticillium Wilt of ‘Russet Burbank’ Potato

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 379-383 ◽  
Author(s):  
Jeremiah K. S. Dung ◽  
Dennis A. Johnson
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Russet Burbank Potato ◽  
Vascular System ◽  
Seed Tuber ◽  
Russet Burbank ◽  
Causal Agent ◽  
Infested Soil ◽  
Premature Senescence ◽  
Infected Seed

Verticillium dahliae, causal agent of Verticillium wilt of potato, persists in soil as microsclerotia and can be found in infected tubers used for seed. The effects of naturally infected tubers and soilborne inoculum on Verticillium wilt symptoms were compared in the greenhouse. Infected and noninfected tubers were grown in infested and noninfested potting soil. Chlorosis and necrosis were measured and converted to area under senescence progress curves (AUSPC). Aboveground stems and progeny tubers were assayed for V. dahliae. Plants from infested soils exhibited significantly greater AUSPC than plants from noninfested soil. Plants grown from infected and noninfected tubers had similar AUSPC and interactions between infected tubers and infested soil were not observed. The pathogen was isolated from the vascular system of 94% of plants grown in infested soils and 8% of plants grown from infected tubers in noninfested soil. Plants grown in infested soil contained microsclerotia on 46% of stems while plants grown from infected tubers in noninfested soils exhibited microsclerotia on <1% of stems. Infected progeny tubers were only recovered from plants grown in infested soil. Seed tuber infection did not contribute to premature senescence or potential inoculum production, indicating that management efforts should focus on reducing soilborne inoculum.

scholarly journals Management of Verticillium Wilt of Avocado Using Tolerant Rootstocks

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 531 ◽  
Author(s):  
Amnon Haberman ◽  
Leah Tsror (Lahkim) ◽  
Silit Lazare ◽  
Marina Hazanovsky ◽  
Sara Lebiush ◽  
...  
Keyword(s):  
Fungal Infection ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Fungal Pathogen ◽  
Significant Variation ◽  
Genetic Variance ◽  
Causal Agent ◽  
Infested Soil ◽  
Abiotic Constraints ◽  
Massive Tree

The global avocado industry is growing, and farmers are seeking to expand their plantations. However, many lands suitable for avocado planting were previously cultivated with hosts of the soil-borne fungal pathogen Verticillium dahliae, which is the causal agent of Verticillium wilt (VW). VW can seriously impair avocado orchards, and therefore, planting on infested soil is not recommended. The use of different rootstock types allows avocado cultivation in various regions with diverse biotic and abiotic constraints. Hence, we tested whether genetic variance among rootstocks may also be used to manage avocado VW. Six hundred trees, mostly Hass and some Ettinger, grafted on 23 selected rootstocks were evaluated for five years in a highly V. dahliae-inoculated plot for VW symptoms, fungal infection, and productivity. The selected rootstocks displayed a significant variation related to VW tolerance, and productive avocado rootstocks with potential VW tolerance were identified. Moreover, the rootstock productivity appears to correlate negatively to the susceptibility level. In conclusion, planting susceptible rootstocks (e.g., VC66, VC152, and VC26) in infested soil increases the likelihood of massive tree loss and low productivity. Whereas, tolerant rootstocks (e.g., VC804 and Dusa) may restrict VW and enable avocado cultivation on infested soils.

scholarly journals Screening for Resistance to Verticillium Wilt in Spinach and Isolation of Verticillium dahliae from Seed of Spinach Accessions

HortScience ◽  
2012 ◽  
Vol 47 (9) ◽  
pp. 1297-1303 ◽  
Author(s):  
Maria I. Villarroel-Zeballos ◽  
Chunda Feng ◽  
Angela Iglesias ◽  
Lindsey J. du Toit ◽  
James C. Correll
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Crop Production ◽  
Spinacia Oleracea ◽  
Quantitative Resistance ◽  
Germplasm Collection ◽  
Plant Introduction ◽  
Infested Soil ◽  
Wide Range ◽  
North Central Regional

Verticillium dahliae is a pathogen of spinach (Spinacia oleracea) during spinach seed crop production but not in vegetative leafy spinach crops, because plants remain asymptomatic until bolting has been initiated (conversion from vegetative to reproductive growth). The objectives of this research were to evaluate a set of USDA spinach germplasm accessions for resistance to Verticillium wilt and to determine the range in incidence of natural seed infection/infestation in a subset of the USDA spinach accessions screened for resistance. A total of 120 Spinacia spp. accessions from the USDA North Central Regional Plant Introduction Station spinach germplasm collection and 10 commercial S. oleracea hybrids were screened for resistance to V. dahliae in Trials 1, 2, and 3 in 2006, 2007, and 2008, respectively, in greenhouse evaluations. Each accession was grown in either V. dahliae-infested or non-infested potting mix and rated weekly on a seven-step scale from 1 week before bolting to 4 weeks after bolting. A wide range of disease severity ratings was observed among the accessions evaluated. Most of the accessions were highly susceptible. There was no evidence of qualitative resistance but some showed greater levels of quantitative resistance than others. Plants in soil infested with V. dahliae senesced faster and had significantly reduced biomass compared with plants in non-infested soil of the same accession. In addition, in Trial 2 (2007), 34% (20 of 59) of the seed samples assayed of the accessions were infested or infected with V. dahliae; and in Trial 3, (2008) 16% (21 of 130) of the seed samples of the USDA accessions evaluated were infested or infected with V. dahliae, V. tricorpus, or Gibellulopsis nigrescens (formerly known as V. nigrescens). These results are valuable for characterizing potential genetic variability within spinach germplasm for resistance to V. dahliae.

scholarly journals Relationship Between the Inoculum Density of Verticillium dahliae and the Progress of Verticillium Wilt of Olive

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1372-1378 ◽  
Author(s):  
F. J. López-Escudero ◽  
M. A. Blanco-López
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Disease Incidence ◽  
Olive Tree ◽  
Temporal Variations ◽  
Inoculum Density ◽  
Infested Soil ◽  
Initial Inoculum ◽  
Progress Curve ◽  
Olive Trees

An experiment was conducted in microplots which were artificially infested with a defoliating isolate of Verticillium dahliae using seven different treatments of inoculum densities ranging from 0 to 10 microsclerotia per gram of soil (ppg). The experiment was conducted in Andalucía (southern Spain), and the susceptible Spanish olive cv. Picual was used to determine the relationship between pathogen inoculum density and the progress of Verticillium wilt of olive (VWO). The inoculum, produced on a sodium pectate cellophane medium, was found to efficiently infect olive trees. Symptoms first appeared 30 weeks after the trees were transplanted into infested soil. Periods of increasing disease incidence in the following seasons and years were mainly during spring and autumn, particularly in the second year after planting. Olive trees exhibited a high susceptibility to the defoliating pathotype of the pathogen, even at very low inoculum levels; in fact, diseased plants were encountered throughout the experiment regardless of the inoculum density treatment. Inoculum densities greater than 3 ppg in the soil resulted in final disease incidence greater than 50% for the trees after 2.5 years. Therefore, these inoculum densities must be considered very high for olive trees. There were no differences in final disease incidence, mean symptom severity, or area under the disease progress curve between plots infested with 10 or 3.33 ppg, whereas other treatments exhibited lower values for each of these disease parameters. The temporal variations of disease incidence and severity were highly correlated for the higher inoculum density treatments, with r2 values ranging from 0.92 to 0.84 for disease incidence and from 0.93 to 0.88 for severity. However, r2 was slightly lower for the treatments involving lower inoculum densities of the pathogen in microplots. The slopes of the linear regression curves were statistically different for nearly all the inoculum density treatments. Positive correlation was found between the initial inoculum density and final disease incidence values after the study period that was accurately explained by mathematical models. The results suggest that susceptible olive cultivars should not be planted in soils infested with virulent defoliating pathotypes of V. dahliae. Results also clarify that inoculum density levels obtained from field soil analyses can be used for establishing a risk prediction system with a view to controlling VWO in olive tree plantations.

Interactive effects of nitrogen and phosphorus on verticillium wilt of Russet Burbank potato

1994 ◽  
Vol 71 (7) ◽  
pp. 467-481 ◽  
Author(s):  
J. R. Davis ◽  
J. C. Stark ◽  
L. H. Sorensen ◽  
A. T. Schneider
Keyword(s):  
Verticillium Wilt ◽  
Russet Burbank Potato ◽  
Russet Burbank ◽  
Interactive Effects ◽  
Nitrogen And Phosphorus

scholarly journals Incidence and Impact of Verticillium dahliae in Soil Associated with Certified Potato Seed Lots

2013 ◽  
Vol 103 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Jeremiah K. S. Dung ◽  
Philip B. Hamm ◽  
Jordan E. Eggers ◽  
Dennis A. Johnson
Keyword(s):  
Verticillium Dahliae ◽  
Management Practices ◽  
Seed Tuber ◽  
Potato Seed ◽  
Infested Soil ◽  
Seed Tubers ◽  
Field Soils ◽  
Compatibility Group ◽  
High Concentrations ◽  
Certified Potato Seed

Verticillium dahliae causes Verticillium wilt of potato and can be found in soil associated with potato seed tubers. The purpose of this research was to quantify V. dahliae in soil associated with certified seed tubers and determine if this potential inoculum source is related to disease development in the field. Approximately 68% of seed lots assayed contained V. dahliae-infested soil on seed tuber surfaces (seed tuber soil). Over 82% of seed lots contained V. dahliae in loose seed lot soil obtained from bags and trucks used to transport seed tubers. Most samples contained ≤50 CFU/g but some contained >500 CFU/g. Most isolates (93%) were vegetative compatibility group 4A. Populations of V. dahliae in stem sap increased with increasing inoculum densities in field soils only when V. dahliae concentrations in seed tuber soil were low. High concentrations of V. dahliae in seed tuber soil resulted in greater stem sap colonization when V. dahliae inoculum densities in field soil were low (P < 0.01) and resulted in greater pathogen inoculum densities in postharvest field soils (P = 0.04). Seed tubers contaminated with V. dahliae-infested soils may introduce the pathogen into fields not previously cropped to potato or recontaminate those which have received preplant management practices. Long-term management of V. dahliae requires reducing propagules in soil associated with seed lots.

scholarly journals A Real-Time PCR Assay for Detection and Quantification of Verticillium dahliae in Spinach Seed

2012 ◽  
Vol 102 (4) ◽  
pp. 443-451 ◽  
Author(s):  
Dechassa Duressa ◽  
Gilda Rauscher ◽  
Steven T. Koike ◽  
Beiquan Mou ◽  
Ryan J. Hayes ◽  
...  
Keyword(s):  
Real Time ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Real Time Pcr ◽  
The United States ◽  
Infected Seed ◽  
Polymerase Chain ◽  
Reliable Quantification ◽  
Pathogen Dna ◽  
Detection And Quantification

Verticillium dahliae is a soilborne fungus that causes Verticillium wilt on multiple crops in central coastal California. Although spinach crops grown in this region for fresh and processing commercial production do not display Verticillium wilt symptoms, spinach seeds produced in the United States or Europe are commonly infected with V. dahliae. Planting of the infected seed increases the soil inoculum density and may introduce exotic strains that contribute to Verticillium wilt epidemics on lettuce and other crops grown in rotation with spinach. A sensitive, rapid, and reliable method for quantification of V. dahliae in spinach seed may help identify highly infected lots, curtail their planting, and minimize the spread of exotic strains via spinach seed. In this study, a quantitative real-time polymerase chain reaction (qPCR) assay was optimized and employed for detection and quantification of V. dahliae in spinach germplasm and 15 commercial spinach seed lots. The assay used a previously reported V. dahliae-specific primer pair (VertBt-F and VertBt-R) and an analytical mill for grinding tough spinach seed for DNA extraction. The assay enabled reliable quantification of V. dahliae in spinach seed, with a sensitivity limit of ≈1 infected seed per 100 (1.3% infection in a seed lot). The quantification was highly reproducible between replicate samples of a seed lot and in different real-time PCR instruments. When tested on commercial seed lots, a pathogen DNA content corresponding to a quantification cycle value of ≥31 corresponded with a percent seed infection of ≤1.3%. The assay is useful in qualitatively assessing seed lots for V. dahliae infection levels, and the results of the assay can be helpful to guide decisions on whether to apply seed treatments.

scholarly journals Antifungal activity of plant essential oils against Verticillium dahliae Klebahn, the causal agent of verticillium wilt of pepper

2019 ◽  
Vol 34 (1) ◽  
pp. 39-46
Author(s):  
Jelena Lukovic ◽  
Biljana Todorovic ◽  
Svetlana Milijasevic-Marcic ◽  
Emil Rekanovic ◽  
Miroslav Kostic ◽  
...  
Keyword(s):  
Essential Oils ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Harmful Effect ◽  
Causal Agent ◽  
Mentha Piperita ◽  
Black Pine ◽  
Plant Essential Oils ◽  
Two Samples

Biofungicides based on plant oils have some advantages compared to chemical fungicides, especially considering their harmful effect on the environment. Twenty-two essential oils from Germany and Albania were assayed for inhibitory and fungicidal activity against Verticillium dahliae Klebahn, the causal agent of Verticillium wilt of pepper, using the macrodilution fumigant method. The concentrations of oils obtained in the vapour phase were: 0.02, 0.04, 0.08, 0.16 and 0.32 ?l ml-1 with determined minimum inhibitory and fungicidal concentrations. The strongest activity was shown by two samples of mint oil (Mentha piperita L.) at 0.02 ?l ml-1 of air, both from Germany and Albania, followed by plant essential oils of eucalyptus (Eucalyptus globulus Labilardie), black pine (Pinus nigra L.) and cade (Juniperus oxycedrus L.), and all of them were lethal to the pathogen. Nine oils: two samples of mint, cade, eucalyptus, black pine, lavender (Lavandula angustifolia Mill.), sage (Salvia officinalis L.) and rosemary (Rosmarinus officinalis L.) inhibited the growth of Verticillium dahliae, while five oils (two samples of mint, eucalyptus, black pine and cade) showed fungicidal effects on the pathogen. These results showed that mint, eucalyptus, black pine and cade essential oils have a potential for further in vivo experiments against Verticillium dahliae.

scholarly journals Evaluation of Inoculation Methods for Screening Horseradish Cultivars for Resistance to Verticillium dahliae

Plant Disease ◽  
1997 ◽  
Vol 81 (4) ◽  
pp. 356-362 ◽  
Author(s):  
N. Atibalentja ◽  
D. M. Eastburn
Keyword(s):  
Least Squares ◽  
Total Variation ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Coefficient Of Variation ◽  
Good Predictor ◽  
Infested Soil ◽  
Inoculation Methods ◽  
Foliar Symptoms ◽  
Incubation Periods

Four inoculation methods—colonized oatseed, root dip, infested soil, and set dip—were tested in the greenhouse for their effectiveness in identifying horseradish cultivars that are resistant to Verticillium wilt of horseradish. Examination of the inoculum density-disease relationships derived with each of these methods on susceptible (647A) and resistant (769A) cultivars showed that all were effective, though at varying degrees, in differentiating between susceptible and resistant reactions. Results were more consistent with the root dip method as it produced the largest least-squares means difference in wilt index between the two cultivars, the highest r 2, the lowest coefficient of variation, the shortest incubation periods, and the highest incidence of foliar symptoms. Overall, inoculum concentrations accounted for only a small amount of the total variation in wilt index (0.14 ≤ r 2 ≤ 0.73). This observation, in accord with previous reports on other hosts of Verticillium dahliae, would suggest that inoculum densities may not be a good predictor of the severity of Verticillium wilt of horseradish.

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