Decrease in Disease Severity in Sugarbeet in an Established Rhizoctonia Crown and Root Rot Nursery

Fourteen alfalfa cultivars were grown for 2 yr at three locations and evaluated for forage dry matter yield and crown and root rot. Significant differences were found among cultivars for dry matter yield. All cultivars were affected by crown and root rot, most cultivars showing between 20 and 30% of infected tissues. Differences were observed among as well as within the cultivars for disease severity. The frequency of disease-free plants was less than 1.3% of the plants evaluated. Correlation between root rot index and forage yield was −0.87 [Formula: see text] when data were pooled over years and locations.Key words: Lucerne, root rot, cultivar, yield

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Pathogenicity of Fusarium species associated with crown and root rot of wheat (Triticum aestivum) under different condition

Innovaciencia Facultad de Ciencias Exactas Físicas y Naturales ◽

10.15649/2346075x.659 ◽

2019 ◽

Vol 7 (1) ◽

pp. 1-9

Author(s):

Bareen Sidqi Shareef Al-Tovi ◽

Raed Abduljabbar Haleem

Keyword(s):

Disease Severity ◽

Root Rot ◽

Field Experiments ◽

Fusarium Species ◽

Test Tube ◽

Spore Suspension ◽

Wheat Crop ◽

Pathogenicity Test ◽

Crown And Root Rot

This study was conducted to test the pathogenicity of Fusarium species, the causes of crown and root rot disease of wheat crop, under three different conditions (Laboratory, Greenhouse and Field) and to show the best method for pathogenicity among different conditions. Pathogenicity test of six isolates of Fusarium species (F. graminearum, F. oxysporum, F. avenaceum, F. nivale, F. solani and F. udum) was tested on durum (Simeto) cultivar of wheat by test tube method in the laboratory, the tested fungi had substantial effect on seed germination. F. oxysporum showed the highest germination failure (44.44%) which significantly differed with other species. In the greenhouse, seedlings were inoculated by spore suspension at the base of each plant stem. The most virulent fungus after 35 days of inoculation was F. oxysporum (0.78) followed by F. solani (0.70) and F. graminearum (0.66), while the lowest disease severity was recorded by F. udum (0.16). Also in the field pathogenicity experiments of three Fusarium species (F. graminearum, F. oxysporum and F. solani) were performed on a durum (Simeto) and soft (Cham6) cultivars. Spore suspension was applied at the 2- to 3-leaf Zadoks’s growth stage. Disease severity was calculated at two stages of wheat growth (Booting and Ripening).The most virulent fungus was F. graminearum (0.42) that was significantly different from other fungi. This work indicated that F. graminearum, F. oxysporum and F. solani showed higher infection than remaining tested species under threeconditions. Pathogenicity test in laboratory by test tube method (In-vitro) appeared more effective than greenhouse and field experiments

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Macro- and Microelement Fertilizers Influence the Severity of Fusarium Crown and Root Rot of Tomato in a Soilless Production System

HortScience ◽

10.21273/hortsci.34.2.287 ◽

1999 ◽

Vol 34 (2) ◽

pp. 287-291 ◽

Cited By ~ 23

Author(s):

B.K. Duffy ◽

G. Défago

Keyword(s):

Disease Severity ◽

Nutrient Solution ◽

Root Rot ◽

Management Strategy ◽

Ammonium Nitrogen ◽

Mineral Fertilizers ◽

Solution Ph ◽

Host Nutrition ◽

Crown And Root Rot ◽

Plant Pathogen Interactions

Host nutritional variables were evaluated for their effects on the severity of crown and root rot of tomato caused by Fusarium oxysporum f.sp. radicis-lycopersici. Tomato (Lycopersicon esculentum Mill.) seedlings (cv. Bonnie Best) were grown in a pathogen-infested, soilless rockwool system in the greenhouse and were fertilized with a nutrient solution that was amended with macro- and microelements at various rates. Disease was evaluated after 2 weeks using an index of 0 to 4, and plant fresh weight was measured. Regression analysis indicated that disease severity was significantly increased by ammonium-nitrogen [NH4Cl, (NH4)6Mo7O24, and (NH4)2SO4], NaH2PO4·H2O, Fe-EDDHA, MnSO4, MoO3, and ZnSO4·7H2O. Disease severity was reduced by nitrate-nitrogen [Ca(NO3)2·4H2O] and CuSO4·H2O. Low rates of NH4NO3 (39 to 79 mg·L-1 N) reduced disease, but rates above 100 mg·L-1 N increased it. Disease was not affected by MgSO4·7H2O. In all cases, plant growth was inversely related to disease severity. Mineral fertilizers had no effect on nutrient solution pH. This information sheds new light on environmental factors that influence plant-pathogen interactions, and may be applied to develop a management strategy for Fusarium crown and root rot based on host nutrition.

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Influence of Glyphosate on Rhizoctonia Crown and Root Rot (Rhizoctonia solani) in Glyphosate-Resistant Sugarbeet

Weed Science ◽

10.1614/ws-d-11-00027.1 ◽

2012 ◽

Vol 60 (1) ◽

pp. 113-120 ◽

Cited By ~ 7

Author(s):

Kelly A. Barnett ◽

Christy L. Sprague ◽

William W. Kirk ◽

Linda E. Hanson

Keyword(s):

Rhizoctonia Solani ◽

Ammonium Sulfate ◽

Disease Severity ◽

Root Rot ◽

Radial Growth ◽

Field Experiments ◽

Herbicide Treatments ◽

Tolerant Variety ◽

Crown And Root Rot

Previous greenhouse studies with a noncommercial glyphosate-resistant sugarbeet variety indicated that susceptibility to Rhizoctonia crown and root rot could increase after glyphosate was applied. Greenhouse and field experiments were conducted in 2008 and 2009 to determine if glyphosate influenced disease severity in potential commercially available varieties of glyphosate-resistant sugarbeet. In the first greenhouse experiment in 2008, Hilleshög 9027RR, the most tolerant variety to Rhizoctonia crown and root rot, exhibited an increase in disease severity when glyphosate was applied. There were no significant differences between herbicide treatments in Hilleshög 9028RR, and glyphosate decreased disease severity in Hilleshög 9032RR when compared with the no-herbicide treatment. Experiments conducted to determine if glyphosate influenced Rhizoctonia solani growth in vitro indicated that glyphosate did not increase the radial growth of R. solani, except at 10× (190 µg ae ml−1) the normal rate of glyphosate plus ammonium sulfate (AMS). Field and additional greenhouse experiments were conducted using four commercial varieties. Differences in disease severity were observed when comparing varieties, but glyphosate did not significantly influence the severity of Rhizoctonia crown and root rot when compared with the no-herbicide control. Choosing a glyphosate-resistant sugarbeet variety with the best demonstrated tolerance to Rhizoctonia crown and root rot is an important factor in reducing disease severity and maintaining sugarbeet yield.

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Evaluation of Application Methods of Metam Sodium for Management of Fusarium Crown and Root Rot in Tomato in Southwest Florida

Plant Disease ◽

10.1094/pdis.1998.82.8.919 ◽

1998 ◽

Vol 82 (8) ◽

pp. 919-923 ◽

Cited By ~ 28

Author(s):

R. J. McGovern ◽

C. S. Vavrina ◽

J. W. Noling ◽

L. A. Datnoff ◽

H. D. Yonce

Keyword(s):

Lycopersicon Esculentum ◽

Disease Severity ◽

Root Rot ◽

Soil Surface ◽

Metam Sodium ◽

Southwest Florida ◽

Industry Practice ◽

High Disease Severity ◽

Application Methods ◽

Crown And Root Rot

Experiments were conducted during 1992 to 1995 to evaluate the effectiveness of application methods of metam sodium (MS; sodium N-methyldithio-carbamate) for the management of Fusarium crown and root rot (FCRR) caused by Fusarium oxysporum f. sp. radicis-lycopersici in mulched and staked tomatoes (Lycopersicon esculentum Mill.) grown on raised beds in commercial fields in southwest Florida. Efficacy of MS was compared with soil-injection of methyl bromide-chloropicrin (MBC), the current industry practice for production of tomatoes in Flor-ida. The incidence of FCRR was consistently high in nontreated plots (80 to 100%), but disease severity varied by site, and yields were reduced by 10 to 57% at sites with high disease severity when compared to sites treated with MBC at 336 to 448 kg/ha. Application of MBC reduced FCRR incidence in all experiments. Chemigation with MS at 701 or 935 liters/ha into mulched beds using either one or two drip irrigation tubes placed on the soil surface, and soil injection of MS at 935 liters/ha, failed to reduce the disease. The application of MS at 935 liters/ha to the soil surface prior to bed formation produced variable results. Rotovation of MS at the same rate into preformed beds consistently produced reductions in the incidence of FCRR equivalent to those achieved by MBC.

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The epidemiology of common root rot in Manitou wheat: disease progression during the growing season

Canadian Journal of Botany ◽

10.1139/b74-227 ◽

1974 ◽

Vol 52 (7) ◽

pp. 1757-1764 ◽

Cited By ~ 14

Author(s):

P. R. Verma ◽

R. A. A. Morrall ◽

R. D. Tinline

Keyword(s):

Triticum Aestivum ◽

Disease Severity ◽

Plant Development ◽

Root Rot ◽

Growing Season ◽

Cochliobolus Sativus ◽

Infection Rates ◽

Common Root ◽

Common Root Rot ◽

Disease Rating

Common root rot in Triticum aestivum cultivar Manitou caused primarily by Cochliobolus sativus was followed during plant development in 1969, 1970, and 1971 at Matador, Saskatchewan. Plants were sampled at intervals, and three variables based mainly on the occurrence of lesions on subcrown internodes were studied: number of diseased plants per square meter; percentage of diseased plants; and disease rating which integrated percentage of diseased plants and disease severity on each plant. All variables increased with time, and the progression curves in all 3 years were hyperbolic, indicating that the increases were like those of a simple interest disease as described by Van der Plank. In two of the years, almost 100% of the plants were diseased considerably before the end of the season. The transformation proposed by Van der Plank for simple interest diseases, log10[1/(1 − x)], was applied to the percentages of diseased plants, and regressions were calculated. The slopes of these lines (infection rates) were as follows: 1969, 0.99% plants per day; 1970, 1.32%; and 1971, 1.96%. In 1969 the onset of disease was later than in 1970 and 1971, and there was correspondingly less disease at the end of the growing season.

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INFLUENCE OF BIOCHAR AND EARTHWORMS ON PLANT GROWTH, FUSARIUM CROWN AND ROOT ROT, AND MYCORRHIZAL COLONIZATION OF ASPARAGUS

Acta Horticulturae ◽

10.17660/actahortic.2012.950.30 ◽

2012 ◽

pp. 263-270 ◽

Cited By ~ 2

Author(s):

W.H. Elmer

Keyword(s):

Plant Growth ◽

Root Rot ◽

Mycorrhizal Colonization ◽

Crown And Root Rot

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Soil Inoculum Production, Survival, and Infectivity of the Boxwood Blight Pathogen, Calonectria pseudonaviculata

Plant Disease ◽

10.1094/pdis-12-14-1245-re ◽

2015 ◽

Vol 99 (12) ◽

pp. 1689-1694 ◽

Cited By ~ 12

Author(s):

Norm Dart ◽

Chuanxue Hong ◽

Caryn Allen Craig ◽

J. T. Fry ◽

Xinran Hu

Keyword(s):

Root Rot ◽

Soil Inoculum ◽

Foliar Blight ◽

High Inoculum ◽

Inoculum Production ◽

Foliar Pathogen ◽

Leaves And Roots ◽

Crown And Root Rot ◽

Stem Cankers

Boxwood blight caused by Calonectria pseudonaviculata is typically expressed as a foliage disease with aboveground symptoms including defoliation, dieback and formation of dark narrow stem cankers. Whether this pathogen behaves like other Calonectria spp. and has a significant soil phase in the epidemiology of boxwood blight is not known. In this study we observed experimentally that (1) the boxwood blight pathogen consistently forms microsclerotia in artificially inoculated leaves and roots of Buxus spp., (2) soil artificially inoculated with conidia and microsclerotia of this pathogen can cause foliar blight, (3) conidia and microsclerotia can remain viable in soil for up to 3 and at least 40 weeks, respectively (4) and the pathogen can cause crown and root rot to plants only when roots and crowns are directly exposed to relatively high inoculum levels. Our results suggest that C. pseudonaviculata is primarily a foliar pathogen with a potentially epidemiologically significant soil phase.

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Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot

Canadian Journal of Plant Science ◽

10.4141/cjps2012-183 ◽

2013 ◽

Vol 93 (3) ◽

pp. 473-482 ◽

Cited By ~ 8

Author(s):

R. L. Conner ◽

K. F. Chang ◽

S. F. Hwang ◽

T. D. Warkentin ◽

K. B. McRae

Keyword(s):

Disease Severity ◽

Root Rot ◽

Weight Ratio ◽

Field Pea ◽

Control Measures ◽

Effective Control ◽

Yield Losses ◽

Plant Vigour ◽

Shoot Weight ◽

High Yields

Conner, R. L., Chang, K. F., Hwang, S. F., Warkentin, T. D. and McRae, K. B. 2013. Assessment of tolerance for reducing yield losses in field pea caused by Aphanomyces root rot. Can. J. Plant Sci. 93: 473–482. Aphanomyces root rot, caused by Aphanomyces euteiches Drechs., is a serious disease of peas (Pisum sativum) that can severely reduce seed yield, and few effective control measures are available. The development of pea cultivars with tolerance or partial resistance to Aphanomyces root rot is generally considered to be one of the best options to reduce yield loss. A 4-yr field study was conducted at disease-free sites and at an Aphanomyces root rot site to compare the responses of cultivars and lines in the presence and absence of Aphanomyces root rot, identify breeding lines with tolerance and to evaluate the effects of tolerance on plant growth, disease severity and yield. At the Aphanomyces root rot site, a second test was established in which the phosphite fungicide Phostrol™ was applied as a soil drench treatment to the pea cultivars and lines. Aphanomyces root rot reduced seedling emergence, biomass production and yield in the susceptible pea genotypes. However, line 00-2067 consistently produced relatively high yields at all the field sites. At the Aphanomyces root rot site, yield was closely associated with plant vigour and shoot weight. Small, but significant, differences (P<0.05) in disease severity were observed between susceptible cultivars and tolerant lines indicating that the lines producing high yields at the Aphanomyces root rot site are tolerant rather than partially resistant. The root/shoot weight ratio was very low in the tolerant lines, indicating that even though their root systems were reduced and severely damaged by root rot, they were still able to produce high yields under favourable conditions for the disease. Drench application of the fungicide Phostrol™ did not significantly reduce root rot severity or improve the performance of any of the pea cultivars or lines.

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