Effects of Host Age on Development of Cavity Spot Disease of Carrots Caused by Pythium coloratum in Western Australia Khaled

1997 ◽  
Vol 45 (4) ◽  
pp. 727 ◽  
Author(s):  
A. El-Tarabily ◽  
Giles E. St J. Hardy ◽  
Krishnapillai Sivasithamparam
Keyword(s):  
Western Australia ◽  
Infested Soil ◽  
Host Age ◽  
Field Soil ◽  
Spot Disease ◽  
Cavity Spot ◽  
Infested Field ◽  
Time Of Infection ◽  
Pythium Coloratum ◽  
Time Of Harvest

Three experiments were conducted with Pythium coloratum Vaartaja, a causal agent of cavity spot disease of carrots in Western Australia, to study the relationships between host age, time of infection and development of cavity spot lesions. Pythium coloratum was isolated frequently from 3-6-week-old asymptomatic roots of carrots grown in soils infested naturally or artificially with the pathogen. Carrots grown in containers of soil artificially infested with P. coloratum, but not those in naturally infested field soil, developed cavity spot lesions after 6 weeks. Early infection of carrot seedlings at or before 3 weeks by P. coloratum in artificially infested soils followed by their transfer to pathogen-free soil was sufficient to cause cavity spot disease at the time of harvest (16 weeks). The disease levels in this treatment were not different from those transferred to P. coloratum-infested soil. There was no significant (P > 0.05) association between carrot age and the ability of P. coloratum to infect the roots and to cause cavity spot lesions at harvest.

Microbiological differences between limed and unlimed soils and their relationship with cavity spot disease of carrots (Daucus carota L.) caused by Pythium coloratum in Western Australia

1996 ◽  
Vol 183 (2) ◽  
pp. 279-290 ◽  
Author(s):  
Khaled A. El-Tarabily ◽  
Giles E. St. J. Hardy ◽  
Krishnapillai Sivasithamparam ◽  
Ipek D. Kurtb�ke
Keyword(s):  
Western Australia ◽  
Daucus Carota ◽  
Daucus Carota L ◽  
Spot Disease ◽  
Cavity Spot ◽  
Pythium Coloratum

Association of Pythium coloratum and Pythium sulcatum with cavity spot disease of carrots in Western Australia

1996 ◽  
Vol 45 (4) ◽  
pp. 727-735 ◽  
Author(s):  
K. A. EL‐TARABILY ◽  
G. E. ST. J. HARDY ◽  
K. SIVASITHAMPARAM
Keyword(s):  
Western Australia ◽  
Spot Disease ◽  
Cavity Spot ◽  
Pythium Coloratum

Amendment of soil with lime or gypsum and its effect on cavity spot disease of carrots (Daucus carota L.) caused by Pythium coloratum

1997 ◽  
Vol 37 (2) ◽  
pp. 265 ◽  
Author(s):  
K. A. El-Tarabily ◽  
G. E. St J. Hardy ◽  
K. Sivasithamparam ◽  
A. G. McKay
Keyword(s):  
Soil Ph ◽  
Daucus Carota ◽  
Calcium Concentration ◽  
Field Trials ◽  
Direct Role ◽  
Daucus Carota L ◽  
Spot Disease ◽  
Application Rates ◽  
Cavity Spot ◽  
Pythium Coloratum

Summary. Glasshouse trials were conducted to examine the effect of lime or gypsum amendments on the development of cavity spot disease of carrots in soil artificially infested with Pythium coloratum. Each amendment was applied to soil from the field at 4000 or 8000 kg/ha. Lime at both application rates significantly (P<0.05) reduced the incidence of the disease. In contrast, both gypsum treatments had no effect on the incidence of cavity spot disease. There was no significant (P>0.05) difference in calcium concentration between carrot roots grown in unamended, lime- or gypsum-amended soil with or without the pathogen. Calcium did not appear to play a direct role in the reduction of cavity spot disease. Under the controlled conditions of this glasshouse trial, reduction in the incidence of cavity spot appeared to be related to the increase in soil pH associated with the application of lime. Field trials at the site of soil collection will confirm whether this mechanism is related to field reduction of the disease following liming.

scholarly journals The potential for the biological control of cavity-spot disease of carrots, caused by Pythium coloratum, by streptomycete and non-streptomycete actinomycetes

1997 ◽  
Vol 137 (3) ◽  
pp. 495-507 ◽  
Author(s):  
KHALED A. EL-TARABILY ◽  
GILES E. ST. J. HARDY ◽  
KRISHNAPILLAI SIVASITHAMPARAM ◽  
ASSEM M. HUSSEIN ◽  
D. IPEK KURTBOKE
Keyword(s):  
Biological Control ◽  
Spot Disease ◽  
Cavity Spot ◽  
Pythium Coloratum

scholarly journals The epidemiology of Sarcocystis spp. in cattle of Western Australia

1992 ◽  
Vol 108 (1) ◽  
pp. 107-113 ◽  
Author(s):  
G. Savini ◽  
J. D. Dunsmore ◽  
I. D. Robertson ◽  
P. Seneviratna
Keyword(s):  
Western Australia ◽  
Host Age ◽  
Semiarid Regions ◽  
Sex Influence ◽  
Sarcocystis Spp ◽  
Artificial Digestion ◽  
Management Factors ◽  
Arid And Semiarid ◽  
Age And Sex

SUMMARYOesophagus samples from 714 cattle from Western Australia were examined by artificial digestion to detect the presence of Sarcocystis spp. The overall prevalence of infection was 52%. The prevalence of infection increased with age and was highest in the entire males (92%). The prevalence was lower in cattle which originated from arid and semiarid regions (9 and 31% respectively) than those from tropical (87%) and temperate (60%) regions. possible reasons for these differences are discussed and it is concluded that environmental and management factors as well as host age and sex influence the prevalence of infection with Sarcocystis spp. in cattle.

scholarly journals Molecular studies of Potato mop-top virus (PMTV) in transgenic N. benthamiana and S. tuberosum

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. 183-185
Author(s):  
A. Germundsson ◽  
M. Sandgren ◽  
H. Barker ◽  
E.I. Savenkov ◽  
J.P.T. Valkonen
Keyword(s):  
Nicotiana Benthamiana ◽  
Transgenic Potato ◽  
Infested Soil ◽  
Systemic Movement ◽  
Potato Plants ◽  
Cp Gene ◽  
Molecular Studies ◽  
Infested Field ◽  
Transgenic Potato Plants ◽  
Potato Mop Top Virus

Resistance to Potato mop-top virus (PMTV) was studied in Nicotiana benthamiana and potato (Solanum tuberosum cv.<br />Saturna) transformed with the coat protein (CP) gene of PMTV. In N. benthamiana plants mechanically inoculated with<br />PMTV, RNA2 was detected in leaves and roots in several plants in the absence of RNA3. When N. benthamiana was<br />grown in infested soil, viral RNA was detected in roots, but no systemic movement of PMTV to above-ground parts was<br />observed. The incidence of PMTV infections was reduced in the CP-transgenic potato plants grown in an infested field<br />in Sweden. However, in infected tubers, all three virus RNAs were detected.

Variation in susceptibility of cultivars of Trifolium subterraneum to Kabatiella caulivora and in pathogenicity of isolates of the fungus as shown in germination-inoculation tests

1975 ◽  
Vol 26 (4) ◽  
pp. 647 ◽  
Author(s):  
K Helms
Keyword(s):  
Western Australia ◽  
New South ◽  
South Australia ◽  
Trifolium Subterraneum ◽  
Leaf Production ◽  
South Wales ◽  
Kabatiella Caulivora ◽  
Susceptible Group ◽  
Time Of Harvest ◽  
Different Parts

Seedlings of six cultivars of Trifolium subterraneum were tested during germination for resistance to Kabatiella caulivora, and gave results comparable with those obtained with seedlings inoculated by spraying at 1–4 weeks after sowing. Advantages of the method were that a large number of seedlings could be screened under uniform conditions with the minimum of time and space. Within the more susceptible group of cultivars, Woogenellup and Bacchus Marsh were usually more susceptible than Yarloop and Mt. Barker; these in turn were more susceptible than Clare, and Clare more susceptible than Daliak. For all cultivars except the highly resistant cultivar, Daliak, there was a correlation between the rate of trifoliolate leaf production and susceptibility to the disease, the most susceptible being those with most leaves expanded at the time of inoculation and with most leaves present at the time of harvest. Physiologic specialization in isolates of the pathogen from different parts of Australia was demonstrated. In general, one isolate from South Australia was more pathogenic than a group of isolates from South Australia, Victoria and Western Australia; these in turn were more pathogenic than one isolate from New South Wales, which was somewhat atypical in culture, and one from Victoria which was markedly atypical in culture.

scholarly journals Field Resistance to Verticillium Wilt in Selected Olive Cultivars Grown in Two Naturally Infested Soils

Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 668-674 ◽  
Author(s):  
C. Trapero ◽  
N. Serrano ◽  
O. Arquero ◽  
C. Del Río ◽  
A. Trapero ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Severe Disease ◽  
Field Trials ◽  
Field Resistance ◽  
Infested Soil ◽  
Wilt Resistance ◽  
Verticillium Wilt Resistance ◽  
Olive Cultivars ◽  
Infested Field ◽  
High Level

The resistance of 11 olive cultivars to Verticillium dahliae was assessed in two experimental field trials. One-year-old rooted olive cuttings from the World Olive Germplasm Bank (IFAPA research center, Córdoba, Spain) were planted in a heavily infested field in Utrera (Sevilla province) and in a moderately infested field in Andújar (Jaén province) of southern Spain. Plants were assessed for Verticillium wilt resistance during 22 months based on disease severity and tree growth. Severe disease symptoms were observed 6 months after planting in both trials. Twenty months after planting in the heavily infested soil, V. dahliae had killed nearly all of the trees of ‘Bodoquera’, ‘Cornicabra’, ‘Manzanilla de Sevilla’, and ‘Picual’, demonstrating the elevated risk of planting susceptible cultivars in a soil heavily infested with V. dahliae. ‘Arbequina’, ‘Koroneiki’, ‘Sevillenca’, and especially ‘Frantoio’, ‘Empeltre’, and ‘Changlot Real’ showed a high level of disease resistance. However, all of them were affected by the disease. Although the field results confirmed the level of resistance previously obtained for these olive genotypes under controlled conditions, there were some discrepancies. This information will be useful in managing the disease and also in selecting new cultivars for the breeding of Verticillium wilt resistance.

scholarly journals CRISPR-Based Isothermal Next-Generation Diagnostic Method for Virus Detection in Sugarbeet

2021 ◽  
Vol 12 ◽  
Author(s):  
Vanitharani Ramachandran ◽  
John J. Weiland ◽  
Melvin D. Bolton
Keyword(s):  
Virus Detection ◽  
Detection Methods ◽  
Target Sequence ◽  
Field Soil ◽  
Human Virus ◽  
Guide Rna ◽  
Highly Sensitive ◽  
Infested Field ◽  
Virus Diagnostics

Rhizomania is a disease of sugarbeet caused by beet necrotic yellow vein virus (BNYVV) that significantly affects sugarbeet yield globally. Accurate and sensitive detection methods for BNYVV in plants and field soil are necessary for growers to make informed decisions on variety selection to manage this disease. A recently developed CRISPR-Cas-based detection method has proven highly sensitive and accurate in human virus diagnostics. Here, we report the development of a CRISPR-Cas12a-based method for detecting BNYVV in the roots of sugarbeet. A critical aspect of this technique is the identification of conditions for isothermal amplification of viral fragments. Toward this end, we have developed a reverse transcription (RT) recombinase polymerase amplification (RPA) for detecting BNYVV in sugarbeet roots. The RT-RPA product was visualized, and its sequence was confirmed. Subsequently, we designed and validated the cutting efficiency of guide RNA targeting BNYVV via in vitro activity assay in the presence of Cas12a. The sensitivity of CRISPR-Cas12a trans reporter-based detection for BNYVV was determined using a serially diluted synthetic BNYVV target sequence. Further, we have validated the developed CRISPR-Cas12a assay for detecting BNYVV in the root-tissue of sugarbeet bait plants reared in BNYVV-infested field soil. The results revealed that BNYVV detection is highly sensitive and specific to the infected roots relative to healthy control roots as measured quantitatively through the reporter signal. To our knowledge, this is the first report establishing isothermal RT-RPA- and CRISPR-based methods for virus diagnostic approaches for detecting BNYVV from rhizomania diseased sugarbeet roots.

Flaming to Reduce Inocula of the Boxwood Blight Pathogen, Cylindrocladium pseudonaviculatum, in Field Soil

2012 ◽  
Vol 13 (1) ◽  
pp. 33 ◽  
Author(s):  
Norman L. Dart ◽  
Sarah M. Arrington ◽  
Sarah M. Weeda
Keyword(s):  
Significant Role ◽  
Plant Tissue ◽  
Field Soil ◽  
Infested Plant ◽  
Infested Field

Infested plant tissue can play a significant role in the epidemiology of boxwood blight in ornamental nursery systems. In an effort to reduce inoculum levels in an infested field in Carroll Co., Virginia, symptomatic plants were removed, collected into a pile, and destroyed by burning using a propane push flamer. The authors investigated whether soil flaming would be effective to reduce viable inocula of C. pseudonaviculatum in the upper layer of soil. Accepted for publication 4 October 2012. Published 26 October 2012.

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