scholarly journals First Report of Verticillium dahliae Causing Artichoke Wilt in California

Plant Disease ◽  
1999 ◽  
Vol 83 (8) ◽  
pp. 782-782 ◽  
Author(s):  
R. G. Bhat ◽  
K. V. Subbarao ◽  
M. A. Bari
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Infected Plant ◽  
Potato Dextrose Agar ◽  
The Other ◽  
Central Coast ◽  
Cynara Scolymus ◽  
First Report ◽  
Vascular Discoloration ◽  
Infested Field

In mid-August 1998, artichoke (Cynara scolymus L.) plants of cultivar Imperial Star in a field in the Salinas area of the central coast of California developed wilt symptoms. The plants were stunted with chlorotic, drooping, and dried leaves near the bottom and middle of the plants as previously described in Italy (1). Diseased plants produced smaller edible buds and, in severe cases, buds were discolored with dried outer bracts. Roots exhibited the characteristic vascular discoloration of Verticillium infection. In one part of the infested field, artichoke was near harvest with 85% of plants showing wilt symptoms with vascular discoloration whereas the other part had a 60-day-old crop with 98% of plants infected. Yield in the field was reduced by as much as 50%. Verticillium dahliae was isolated from infected plant samples on NP-10 medium (2), and isolates were single spored before storing on potato dextrose agar at 4°C. Identity of the pathogen was confirmed based on colony morphology and formation of microsclerotia. In root-dip inoculation tests in the greenhouse, two V. dahliae isolates from artichoke infected 1-month-old artichoke seedlings that wilted within 6 weeks of inoculation. V. dahliae was reisolated from plants showing vascular discoloration. Cross-inoculation studies revealed that artichoke isolates caused a moderate level of disease in lettuce, but only a trace of vascular discoloration in cauliflower. Lettuce isolates caused a severe wilt in artichoke. Cauliflower isolates did not cause wilt in lettuce and caused only slight vascular discoloration in artichoke. This is the first report of a Verticillium wilt of artichoke in California. References: (1) M. Cirulli et al. Plant Dis. 78:680, 1994. (2) L. H. Sorensen et al. Phytopathology 81:1347, 1991.

scholarly journals First report of Verticillium wilt and mortality of Ailanthus altissima caused by Verticillium dahliae and V. albo-atrum sensu lato in Spain

Plant Disease ◽  
2021 ◽  
Author(s):  
Concepció Moragrega ◽  
Júlia Carol ◽  
Enric Bisbe ◽  
Enric Fabregas ◽  
Isidre Llorente
Keyword(s):  
Biological Control ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Mediterranean Basin ◽  
Ailanthus Altissima ◽  
First Report ◽  
Vascular Discoloration ◽  
Invasive Tree ◽  
The Mediterranean ◽  
The Mediterranean Basin

Ailanthus altissima (Mill.) swingle is a highly invasive tree that has become established worldwide, especially in the Mediterranean Basin because of its good drought resistance. Ailanthus altissima is included in the list of Invasive Alien Species of the EU, so measures for eradication and management are required. Assessment for potential biological control agents is of great interest to manage this invasive tree in natural ecosystems. Verticillium dahliae Kleb. and Verticillium nonalfalfae Inderb. et al. (formerly V. albo-atrum Reinke & Berthold) have been reported as the causal agents of Verticillium wilt and mortality of ailanthus (Shall and Davis 2009; Rebbeck et al., 2013; Snyder et al., 2013; Brooks et al. 2020). Ailanthus trees with Verticillium wilt symptoms (wilt, premature defoliation, terminal dieback, yellow vascular discoloration, and mortality) were detected for the first time in 2007 in Celrà (42.040466N, 2.864436E) (Catalonia, Northeastern Spain), then spread to neighboring ailanthus populations. In 2018, ailanthus trees in a 570 km2 area in Catalonia were surveyed for disease symptoms. The incidence of wilt disease in ailanthus trees in forest ecosystems ranged from 50 to 90%, and the severity, 60 to 92%. One hundred and fifty branch samples showing wilt symptoms were collected and disinfected by immersion in 1% sodium hypochlorite for 2 min, then cut into 5mm pieces. These were placed onto PDA plates and incubated at 22.5 °C and 12 h light photoperiod for 7-10 days. Eighty-four tentative Verticillium sp. isolates were recovered and subcultured on modified water agar (WA-p) and PDA for identification (Inderbitzin et al. 2011, 2013). The majority of isolates (77 %) were identified as V. dahliae based on morphology; production of brown-pigmented microsclerotia and conidia features and dimensions (5.7 ± 0.9 μm long). Sequencing of mycelial DNA using primer pair ITS1-F and ITS4, resulted in consensus sequences of 503 bp. BLASTn analysis of ITS sequence of native isolate VdGi688 gave 100% identity to the ITS sequences of V. dahliae type strain PD322 (92% coverage) and Vd16_9 (100% coverage). In addition, 23% isolates morphologically corresponded to V. albo-atrum or V. nonalfalfae; melanized resting mycelia and round to oval-shaped conidia (5.2 ± 0.9 μm × 2.2 ± 0.5 μm). The ITS consensus sequence (544 bp) of native isolate VaaGi02 gave 99% identity (90-100 % coverage) to V. albo-atrum isolates CBS 127169, PSU 140, Vaa_TN1 and to V. nonalfalfae type PD592, CBS5451.88 and Vert 18. Sequences from isolates VdGi688 and VaaGi02 were deposited in GenBank as MW624723 and MW624724, respectively. Koch’s postulates for seven V. dahliae isolates and eight V. albo-atrum isolates were fulfilled by injection of 1 mL of 1 x 107 conidia/mL suspension into the stem of A. altissima seedlings under greenhouse conditions. Six plants were inoculated per isolate in two independent experiments. Control plants were inoculated with sterile distilled water. All isolates caused leaf chlorosis, defoliation, and apical stem death, as well as internal necrosis and vascular discoloration. Control plants remained asymptomatic. The pathogens were re-isolated from internal symptomatic tissues of inoculated plants. To our knowledge, this is the first report of V. dahliae and V. albo-atrum sensu lato causing Verticillium wilt on A. altissima in Spain. The study suggests the potential of native isolates of Verticillum spp. in the biological control of ailanthus in the Mediterranean Basin. This work was funded by the Diputació de Girona (Spain) (2017/8719, 2019/3091, 2020/7565, and 2021/1468).

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae Impacting Ailanthus altissima in Virginia, U.S.A.

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1558 ◽  
Author(s):  
R. K. Brooks ◽  
A. L. Snyder ◽  
E. A. Bush ◽  
S. M. Salom ◽  
A. Baudoin
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Ailanthus Altissima ◽  
First Report

scholarly journals First Report of Occurrence of Eggplant Wilt Caused by Verticillium dahliae in Korea

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1152-1152
Author(s):  
S. K. Kim ◽  
S. S. Hong ◽  
K. W. Kim ◽  
E. W. Park
Keyword(s):  
Verticillium Dahliae ◽  
Solanum Melongena ◽  
Morphological Characteristics ◽  
Wilt Disease ◽  
Potato Dextrose Agar ◽  
First Report ◽  
Vascular Tissues ◽  
Fungal Isolates ◽  
Pathogenicity Tests ◽  
Root Cutting

A wilt disease occurred on greenhouse-grown eggplants (Solanum melongena L.) at Hanam and Yeojoo, Korea, in 1997. Lower leaves on the 2-month-old wilted eggplants exhibited gradual yellowing, interveinal necrosis, and marginal crinkling and dropped prematurely. Vascular tissues of diseased stems were discolored and turned black. Vertical sections of the stems revealed that the pith had been colonized by the fungus. The disease progressed from lower parts of the plants upward. Incidence of diseased eggplants in greenhouses was 5% on 23 May 1997. Although the incidence increased to 10% on 13 June, it remained constant through early July. Fungal isolates from discolored vascular tissues were initially whitish to cream color on potato-dextrose agar, which turned black due to the formation of microsclerotia. The fungus also produced abundant verticillate conidiophores with phialides and conidia. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium dahliae Klebahn. Pathogenicity tests by root cutting, root dipping, or soil drenching resulted in similar symptoms observed in the naturally infected eggplants. Symptoms were first observed on lower leaves of each eggplant 3 weeks after inoculation. Isolation from symptomatic leaves of the inoculated eggplants yielded V. dahliae. This is the first report of occurrence of Verticillium wilt of eggplant in Korea.

scholarly journals Characterization of Verticillium dahliae Isolates and Wilt Epidemics of Pepper

Plant Disease ◽  
2003 ◽  
Vol 87 (7) ◽  
pp. 789-797 ◽  
Author(s):  
R. G. Bhat ◽  
R. F. Smith ◽  
S. T. Koike ◽  
B. M. Wu ◽  
K. V. Subbarao
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Random Amplified Polymorphic Dna ◽  
Disease Incidence ◽  
Bell Pepper ◽  
Central Coast ◽  
Minor Variation ◽  
Bell Peppers ◽  
Compatibility Group

Epidemics of Verticillium wilt in pepper fields of the central coast of California and isolates of Verticillium dahliae associated with these epidemics were characterized. The mean incidence of wilted plants per field ranged from 6.3 to 97.8% in fields with Anaheim, jalapeno, paprika, or bell peppers. In general, incidence of wilt in jalapeno and bell pepper crops was lower than in crops of other types of pepper. Inoculum density of V. dahliae in the surveyed pepper fields ranged from 2.7 to 66.6 microsclerotia g-1 dry soil, and the correlation between disease incidence and density of microsclerotia was high (r = 0.81, P < 0.01). Distribution of Verticillium wilt was aggregated in a majority of the pepper fields surveyed, but the degree of aggregation varied. Vegetative compatibility group (VCG) characterization of 67 isolates of V. dahliae indicated that 67% belonged to VCG 2, 22% to VCG 4, and 11% to a new group, designated VCG 6. The pathogenicity of isolates of V. dahliae from bell pepper and tomato plants was tested by inoculating 1-month-old bell pepper (cv. Cal Wonder) and tomato (cv. EP 7) seedlings and incubating the inoculated plants in the greenhouse. Seedlings of bell pepper were susceptible only to the isolates of V. dahliae from pepper, whereas seedlings of tomato were susceptible to both pepper and tomato isolates. Pepper isolates belonging to VCG 2, VCG 4, and VCG 6 were highly pathogenic to bell pepper and chili pepper. Temperatures between 15 and 25°C were optimal for mycelial growth of a majority of isolates of V. dahliae. Molecular characterization of pepper isolates of V. dahliae using a polymerase chain reaction (PCR)-based random amplified polymorphic DNA (RAPD) technique revealed minor variation among these isolates, but unique polymorphic banding patterns were observed for isolates belonging to VCG 6. Verticillium wilt of pepper is a major production constraint in the central coast of California. More aggressive isolates of V. dahliae may have been selected in this region as a result of intensive cropping practices.

scholarly journals First report of Verticillium dahliae causing verticillium wilt on Stevia rebaudiana in Europe

2019 ◽  
Vol 101 (4) ◽  
pp. 1291-1291 ◽  
Author(s):  
Daniele Da Lio ◽  
Luigi De Martino ◽  
Silvia Tavarini ◽  
Barbara Passera ◽  
Luciana Gabriella Angelini ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Stevia Rebaudiana ◽  
First Report

First report of Verticillium dahliae causing Verticillium wilt on kiwifruit in Ordu, Turkey

2019 ◽  
Vol 102 (1) ◽  
pp. 221-222 ◽  
Author(s):  
Muharrem Türkkan ◽  
Nusret Şahin ◽  
Göksel Özer ◽  
Zeynep Evgin ◽  
Mehmet Yaman ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
First Report

scholarly journals First report of Verticillium wilt on cultivated radish caused by Verticillium dahliae Kleb. in China

2019 ◽  
Vol 101 (3) ◽  
pp. 777-777
Author(s):  
Wenxue Yan ◽  
Baoju Li ◽  
Ali Chai ◽  
Yanxia Shi ◽  
Jianjun Shi ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
First Report ◽  
Verticillium Dahliae Kleb

Spatial Patterns of Microsclerotia of Verticillium dahliae in Soil and Verticillium Wilt of Cauliflower

1997 ◽  
Vol 87 (3) ◽  
pp. 325-331 ◽  
Author(s):  
C. L. Xiao ◽  
J. J. Hao ◽  
K. V. Subbarao
Keyword(s):  
Spatial Patterns ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Binomial Distribution ◽  
Disease Incidence ◽  
Soil Samples ◽  
Random Pattern ◽  
Parameter Estimates ◽  
Regular Pattern ◽  
Vascular Discoloration

The spatial patterns of microsclerotia of Verticillium dahliae in soil and wilt symptoms on cauliflower were determined at three sites in each of two fields in 1994 and 1995. Each site was an 8 × 8 grid divided into 64 contiguous quadrats (2 by 2 m each). Soil samples were collected to a depth of 15 cm with a probe (2.5 cm in diameter), and samples from four sites in each quadrat were bulked. Plants in each quadrat were cut transversely, and the number of plants with vascular discoloration and the number without discoloration were recorded. The soil was assayed for microsclerotia by the modified Anderson sampler technique. Lloyd's index of patchiness (LIP) was used as an indicator to evaluate the aggregation of microsclerotia in the field. Spatial autocorrelation and geostatistical analyses were also used to assess the autocorrelation of microsclerotia among quadrats. The LIP for microsclerotia was greater than 1, indicating aggregation of propagules; however, the degree of aggregation at most sites was not high. Significant autocorrelation within or across rows was detected in some spatial autocorrelograms of propagules, and anisotropic patterns were also detected in some oriented semivariograms from geostatistical analyses for microsclerotia, indicating the influence of bed preparation in the fields on pathogen distribution. The parameter estimates p and θ in the beta-binomial distribution and the index of dispersion (D) associated with the distribution were used to assess the aggregation of diseased plants at each site. A random pattern of wilt incidence was detected at 7 of 12 sites, and an aggregated pattern was detected at 5 of 12 sites. The degree of aggregation was not high. A regular pattern of wilt severity was detected at all sites. The high disease incidence (77 to 98%) observed at 11 of the 12 sites could be explained by high inoculum density.

scholarly journals First Report of Verticillium Wilt Caused by Verticillium dahliae on Mango Trees (Mangifera indica) in Southern Spain

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 380-380 ◽  
Author(s):  
L. Baeza-Montañez ◽  
R. Gómez-Cabrera ◽  
M. D. García-Pedrajas
Keyword(s):  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Mangifera Indica ◽  
Southern Spain ◽  
Reference Sequence ◽  
Universal Primers ◽  
First Report ◽  
Wide Range ◽  
Race 1 ◽  
Disease Rating

Verticillium wilt, primarily caused by Verticillium dahliae Klebahn and V. albo-atrum Reinke & Berthold, affects a wide range of economically important crops. This disease is an increasing problem in areas where young mango trees are planted on land previously planted in vegetable crops. In 2008, symptoms of Verticillium wilt were observed in mango cvs. Kent and Osteen in the subtropical fruit-producing area of Málaga in southern Spain. In a new mango grove of cv. Kent, previously planted in potatoes and tomatoes, ~20% of 200 1-year-old trees had one-sided branch dieback. In many of these trees the symptoms expanded, leading to decline and eventual death. Cross sections of affected branches revealed brown vascular discoloration. Verticillium was isolated from surface-sterilized segments of symptomatic branches placed on acidic potato dextrose agar (PDA). Plates were incubated at 24°C. After 3 days, slow-growing colonies were transferred to PDA. Verticillium was similarly isolated from symptomatic potato plants grown in a nearby field. Identification of V. dahliae was initially based on morphology and further confirmed by molecular methods. All isolates tested produced microsclerotia, a defining feature that distinguishes V. dahliae from V. albo-atrum. For molecular characterization, V. dahliae specific primers 19 and 22 (1) and universal primers ITS1 and ITS4, which amplify the rRNA internal transcribed spacer (ITS) region (4), were used. Bands of expected size were amplified with both primer combinations. ITS fragments were sequenced and identical to the V. dahliae reference sequence (GenBank AY555948) (3). Pathogenicity assays were conducted with a selected isolate from mango using tomato plants from the susceptible line ‘Moneymaker’ and the near isogenic ‘Motabo’ line carrying the Ve gene conferring resistance to race 1 isolates. Five 1-month-old plants (four-leaf stage) were inoculated by root immersion in a suspension of 107 conidia/ml. Five control plants were mock inoculated with distilled water. As a positive control, five plants were inoculated with the previously described race 1 strain Dvd-T5 (2), which induces severe symptoms in susceptible tomato cultivars. Symptoms were scored visually at various time points up to 40 days by a 0 to 5 scale in which 0 = negligible chlorosis or wilting, 1 = chlorosis and wilting and/or curling in individual leaves, 2 = necrosis in leaves, 3 = at least one branch dead, 4 = wilt and/or chlorosis in upper leaves and/or two or more branches dead, and 5 = plant dead or all leaves and most of stem necrotic. The isolate from mango caused typical Verticillium wilt symptoms with a mean disease rating of 3.6 at 40 days postinoculation in both lines. The mean disease rating for Dvd-T5 in Moneymaker 40 days postinoculation was 4.0. V. dahliae was reisolated from symptomatic plants but not from noninoculated controls. To our knowledge, this is the first report of Verticillium wilt on mango in Spain. More problems with Verticillium wilt are expected because of the increasing planting of mango in fields previously dedicated to horticultural crops. References: (1) J. H. Carder et al. Modern Assays for Plant Pathogenic Fungi: Identification, Detection and Quantification. CAB International, Oxford, 1994. (2) K. F. Dobinson et al. Can. J. Plant. Pathol. 18:55, 1996. (3) M. P. Pantou et al. Mycol. Res. 109:889, 2005. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Amplification. Academic Press, San Diego, 1990.

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