scholarly journals Characterization of Fusarium Root Rot Isolates from Sugar Beet by Growth and Virulence at Different Temperatures and Irrigation Regimes

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 1039-1042 ◽  
Author(s):  
R. M. Harveson ◽  
C. M. Rush
Keyword(s):  
Sugar Beet ◽  
Root Rot ◽  
Disease Incidence ◽  
Fusarium Root Rot ◽  
Root Diseases ◽  
Vascular Elements ◽  
Different Temperatures ◽  
Infested Field ◽  
Half Strength ◽  
Growth Differences

Fusarium root rot, caused by Fusarium oxysporum f. sp. betae is one of several root diseases damaging to sugar beet production in Texas. As a primary symptom, most isolates produce a severe tip rot on the distal end of the taproot, in addition to discoloration of vascular elements and wilting. Tip rot distinguishes Fusarium root rot from another F. oxysporum f. sp. betae-incited disease, Fusarium yellows, which induces vascular discoloration and wilting but no root rot. This study was conducted to further characterize a selection of five Texas F. oxysporum f. sp. betae isolates representing different vegetative compatibility groupings, symptom types (tip rot, and non-tip rot), and hosts. Radial growth at six temperatures was measured for each isolate in culture on half-strength potato dextrose agar. Significant growth differences were detected, indicating a substantial amount of variation among the isolates. Virulence of isolates was evaluated by inoculating 6-week-old sugar beet plants with a microspore suspension and transplanting them into infested field soil. The plants were incubated at 20 and 30°C in controlled temperature boxes within the greenhouse and grown under two different irrigation schedules. After 6 weeks, plants were harvested and assigned a root disease rating, and root and foliar dry weights were determined. Disease ratings among isolates at 30°C resulted in three isolates (all tip rot isolates) being severe, one mild, and one intermediate. At 20°C, only one isolate caused appreciable root damage. Irrigation treatments had no effect on disease incidence or severity. Significant differences in colony diameter growth and virulence among isolates at the two temperatures provide further evidence of variation among Texas F. oxysporum f. sp. betae populations. Results also suggest that the tip rot phenotype may be induced by some genetic factor unique to tip rot isolates. Therefore, the form name F. oxysporum f. sp. radicis-betae is proposed for those isolates from Texas causing a tip rot.

scholarly journals Cytological Aspects of Compost-Mediated Induced Resistance Against Fusarium Crown and Root Rot in Tomato

2002 ◽  
Vol 92 (4) ◽  
pp. 424-438 ◽  
Author(s):  
Benoît Pharand ◽  
Odile Carisse ◽  
Nicole Benhamou
Keyword(s):  
Induced Resistance ◽  
Root Rot ◽  
Disease Incidence ◽  
Disease Suppression ◽  
Gold Complex ◽  
Peat Moss ◽  
Fungal Colonization ◽  
Pythium Oligandrum ◽  
Vascular Elements ◽  
Crown And Root Rot

The potential of a pulp and paper mill residues compost for the control of crown and root rot of greenhouse-grown tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici was ultrastructurally investigated. Peat moss amended with compost substantially reduced disease-associated symptoms. Addition of Pythium oligandrum to either peat moss alone or peat moss amended with compost resulted in a considerable reduction in disease incidence compared with controls grown in peat moss alone. Histological and cytological observations of root samples from Fusarium-inoculated plants revealed that the beneficial effect of compost in reducing disease symptoms is associated with increased plant resistance to fungal colonization. One of the most prominent facets of compost-mediated induced resistance concerned the formation of physical barriers at sites of attempted fungal penetration. These structures, likely laid down to prevent pathogen ingress toward the vascular elements, included callose-enriched wall appositions and osmiophilic deposits around the sites of potential pathogen ingress. Invading hyphae, coated by the osmiophilic material, showed marked cellular disorganization. The use of the wheat germ agglutinin-ovomucoid-gold complex provided evidence that the wall-bound chitin was altered in severely damaged hyphae. A substantial increase in the extent and magnitude of the cellular changes induced by compost was observed when P. oligandrum was supplied to the potting substrate. This finding corroborates the current concept that amendment of composts with specific antagonists may be a valuable option for amplifying their beneficial properties in terms of plant disease suppression.

scholarly journals Interaction of Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani as root rot pathogens of Cucumis melo

2019 ◽  
Vol 45 (4) ◽  
pp. 355-360
Author(s):  
Maria Alice Formiga Porto ◽  
Márcia Michelle de Queiroz Ambrósio ◽  
Selma Rogéria de Carvalho Nascimento ◽  
Beatriz Letícia Silva da Cruz ◽  
Taffarel Melo Torres
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Root Rot ◽  
Cucumis Melo ◽  
Yield Loss ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Fresh Weight ◽  
Root Diseases ◽  
Mixed Inoculum

ABSTRACT Root diseases represent one of the main reasons for yield loss in melon crops, especially root and stem rots caused by pathogens like the fungi Fusarium solani (Fs), Macrophomina phaseolina (Mp) and Rhizoctonia solani (Rs), frequently observed in muskmelon either alone or in combination. The objective of this study was to evaluate the effect of the interaction between the pathogens Fs, Mp and Rs on the incidence and severity of root rot and muskmelon development. Two greenhouse experiments were performed using plastic pots with substrate infested with each pathogenic agent alone or in combination. The second experiment was conducted in the same pots that were used in the first experiment. In the first experiment, the disease incidence was higher for the treatment with Fs alone. In the second experiment, the disease incidence and severity were greater for treatment Fs + Rs than for Fs alone. Macrophomina phaseolina was the most commonly isolated pathogen when applied to the plants in a paired mixed inoculum (Fs + Mp and Mp + Rs) in the first experiment. In the second experiment, Fs was more prevalent than the other studied pathogens. Soil infested with Fs had the lowest fresh weight of muskmelon. The pathogens Fs and Mp were more competitive than Rs.

scholarly journals Two sugar beet chitinase genes,BvSP2andBvSE2, analysed with SNP Amplifluor-like markers, are highly expressed after Fusarium root rot inoculations and field susceptibility trial

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5127 ◽  
Author(s):  
Raushan Yerzhebayeva ◽  
Alfiya Abekova ◽  
Kerimkul Konysbekov ◽  
Sholpan Bastaubayeva ◽  
Aynur Kabdrakhmanova ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Candidate Genes ◽  
Root Rot ◽  
Field Trial ◽  
Negative Impact ◽  
Mrna Level ◽  
Strong Association ◽  
Control Level ◽  
Breeding Line ◽  
Fusarium Root Rot

BackgroundThe pathogens fromFusariumspecies can cause Fusarium root rot (RR) and other diseases in plant species including sugar beet (Beta vulgarisL.), and they have a strong negative impact on sugar beet yield and quality.MethodsA total of 22 sugar beet breeding lines were evaluated for the symptoms of RR after inoculation withFusarium oxysporumSch., isolate No. 5, and growth in a field trial. Two candidate genes for RR resistance,BvSP2andBvSE2, encoding chitinases Class IV and III, respectively, were previously identified in sugar beet, and used for genotyping using modern Amplifluor-like single nucleotide polymorphism (SNP) genotyping approach. The qPCR expression analysis was used to verify responses of the candidate genes for RR infections.ResultsA strong association of two SNP markers forBvSP2andBvSE2with resistance to RR in sugar beet was found in our study. Very highBvSP2expression (100-fold compared to Controls) was observed in three RR resistant accessions (2182, 2236 and KWS2320) 14 days after inoculation which returned to the control level on Day 18. RR sensitive breeding line 2210 showed a delay in mRNA level, reaching maximal expression ofBvSP218 days after inoculation. The geneBvSE2, showed a strong expression level in leaf samples from the infected field trial only in the breeding line 2236, which showed symptoms of RR, and this may be a response to other strains ofF. oxysporum.

Influence of glyphosate on Rhizoctonia and Fusarium root rot in sugar beet

2006 ◽  
Vol 62 (12) ◽  
pp. 1182-1192 ◽  
Author(s):  
Rebecca L Larson ◽  
Amy L Hill ◽  
Ann Fenwick ◽  
Andrew R Kniss ◽  
Linda E Hanson ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Root Rot ◽  
Fusarium Root Rot

Evaluation of Resistance to Cylindrocladium Parasiticum of Runner-Type Peanut in The Greenhouse and Field

2008 ◽  
Vol 35 (2) ◽  
pp. 139-148 ◽  
Author(s):  
W. B. Dong ◽  
T. B. Brenneman ◽  
C. C. Holbrook ◽  
A. K. Culbreath
Keyword(s):  
Root Rot ◽  
Disease Incidence ◽  
Similar Reaction ◽  
Effective Parameters ◽  
Cylindrocladium Parasiticum ◽  
Infested Field ◽  
Greenhouse Screening ◽  
Peanut Cultivars ◽  
Moderately Resistant ◽  
Greenhouse Tests

Abstract Identification and utilization of peanut cultivars with resistance to Cylindrocladium black rot (CBR) is a desirable approach to manage this disease. The objectives of this study were to improve greenhouse and field screening techniques for resistance to CBR, and to evaluate the reaction of selected runner-type peanut genotypes. Georgia-02C (moderately resistant to CBR) and C-99R (CBR-susceptible) were used in comparing the effectiveness of different inoculation methods in the greenhouse. Disease development was affected by both size and density of microsclerotia in soil. Use of microsclerotia at a size of ≥150 to <250 µm and a density of 1 to 5 microsclerotia/g soil provided the best separation the CBR-resistant cultivar Georgia-02C and the susceptible C-99R based on root rot severity. Genotypes with varying resistance to CBR were evaluated by growth in a naturally infested field, and by inoculating plants in the field and greenhouse. Disease incidence and severity at harvest were the most effective parameters for evaluating CBR resistance in the field and greenhouse, respectively. The cultivars Georgia-02C and Georganic had the lowest disease incidence, whereas C-99R and DP-1 had the highest disease incidence in a naturally infested field in 2005 and 2006. Incidence of CBR was moderate for Georgia-01R in both years, but was inconsistent for C34-24-85. Georgia-02C and Georganic also showed partial resistance to CBR in greenhouse tests. Inoculated plants in the field had similar reaction with Georgia-02C and Georganic showing higher CBR resistance than C-99R and DP-1 in both 2006 and 2007. The root rot severities for genotypes Georgia-02C and Georganic were lower than those for C-99R and DP-1. Incidence of CBR in the naturally infested field was significantly correlated with CBR incidence in the inoculated plants in the field (r  =  0.84, P ≤ 0.01), but neither was correlated with disease ratings for greenhouse experiments. Peanut genotypes are most reliably screened by inoculating plants in the field or using uniformly infested fields. Further study is needed to improve greenhouse screening procedures.

scholarly journals The Influence of Irrigation Frequency and Cultivar Blends on the Severity of Multiple Root Diseases in Sugar Beets

Plant Disease ◽  
2002 ◽  
Vol 86 (8) ◽  
pp. 901-908 ◽  
Author(s):  
R. M. Harveson ◽  
C. M. Rush
Keyword(s):  
Sugar Beet ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Multiple Root ◽  
Root Disease ◽  
Irrigation Frequency ◽  
Viral Pathogen ◽  
Beet Root ◽  
Root Diseases ◽  
Sugar Beet Root

The effects of cultivar mixtures and two irrigation frequency treatments were evaluated over two seasons for their impact on a complex of sugar beet root diseases in three fields infested with the fungal pathogens Aphanomyces cochliodes, Fusarium oxysporum f. sp. radicis-betae, Rhizoctonia solani, and the viral pathogen Beet necrotic yellow vein virus (BNYVV). Irrigations after emergence consisted of two or five (two 1994 studies) and three or six (1995 study) applications of water for dry and wet treatments, respectively. Cultivar treatments included MH9155, HH67, Ranger, Rhizosen, and four combinations of these same cultivars. Disease progress was monitored through destructive sampling of plants exhibiting foliar symptoms typical of root disease during the season. At harvest, data on root and sucrose yields, sucrose percentage, and a root disease index were collected. No significant irrigation × cultivar treatment interactions were observed. Few significant differences were observed between irrigation treatments involving measured yield components. Reduced irrigations however, resulted in significantly lower disease incidence in all three repeated experiments when cultivar treatments were combined. No added benefits were observed for increasing yield or decreasing root disease by planting mixed cultivars, compared to the same cultivars planted individually. Several regionally adapted cultivars performed as well or better than mixtures under the unusually high levels of disease pressure in test fields. When few alternative options are available, sugar beet growers may still benefit from reducing irrigations, and growing locally adapted cultivars in soils severely infested with root pathogens.

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