Selection for Resistance to the Rhizoctonia-Bacterial Root Rot Complex in Sugar Beet

The Rhizoctonia-bacterial root rot complex continues to be a concerning problem in sugar beet production areas. To investigate resistance to this complex in 26 commercial sugar beet cultivars, field studies and greenhouse studies with mature roots from the field were conducted with Rhizoctonia solani anastomosis group 2-2 IIIB strains and Leuconostoc mesenteroides. Based on means for the 26 cultivars in the 2010 and 2011 field studies, fungal rot ranged from 0 to 8%, bacterial rot ranged from 0 to 37%, total internal rot ranged from 0 to 44%, and surface rot ranged from 0 to 52%. All four rot variables resulted in significant (P < 0.0001) cultivar differences. Based on regression analysis, strong positive relationships (r2 from 0.6628 to 0.9320; P < 0.0001) were present among the rot variables. When ranking cultivars, the most consistent rot variable was surface rot, because 12 of 13 variable–year combinations had significant (P ≤ 0.05) correlations. When cultivar ranking in greenhouse assays was compared, there was frequently a positive correlation with storage data but no relationship with field results. Thus, the greenhouse assays will identify storage rot resistance but field screening will be required to find resistance to this rot complex in the field.

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Interaction of Sugar Beet Host Resistance andRhizoctonia solaniAG-2-2 IIIB Strains

Plant Disease ◽

10.1094/pdis-11-12-1078-re ◽

2013 ◽

Vol 97 (9) ◽

pp. 1175-1180 ◽

Cited By ~ 6

Author(s):

Carl A. Strausbaugh ◽

Imad A. Eujayl ◽

Leonard W. Panella

Keyword(s):

Sugar Beet ◽

Root Rot ◽

Weak Interactions ◽

Block Design ◽

Field Studies ◽

Preliminary Evidence ◽

Economic Losses ◽

Resistant Lines ◽

Crown And Root Rot ◽

Different Strains

Rhizoctonia crown and root rot caused by Rhizoctonia solani can cause serious economic losses in sugar beet fields. Preliminary evidence suggests that there could be interactions between different strains and resistance sources. Thus, field studies were conducted to determine whether nine R. solani AG-2-2 IIIB strains varied for virulence when compared with a noninoculated check and interacted with five sugar beet lines (four resistant lines and a susceptible check). The studies were arranged in a randomized complete block design with six replications. Roots were evaluated for surface rot and internal fungal and bacterial rot in September. All strains were virulent on the susceptible check, FC901/C817, and had a similar ranking (r = 0.80 to 0.97; P = 0.0096 to <0.0001) regardless of disease variable. Line FC709-2 was resistant (response not different from noninoculated check, P ≥ 0.1042) to all strains, while the strain responses resulted in weak interactions with less-resistant lines in 14 of 19 variable-year combinations. Because most commercial sugar beet cultivars contain low to intermediate resistance to Rhizoctonia crown and root rot, the strain used to screen should be considered in order to maintain consistent responses between nurseries and commercial fields.

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Management of Severe Curly Top in Sugar Beet with Insecticides

Plant Disease ◽

10.1094/pdis-01-12-0106-re ◽

2012 ◽

Vol 96 (8) ◽

pp. 1159-1164 ◽

Cited By ~ 8

Author(s):

Carl A. Strausbaugh ◽

Erik J. Wenninger ◽

Imad A. Eujayl

Keyword(s):

Sugar Beet ◽

Insect Pest ◽

Severe Disease ◽

Field Studies ◽

Seed Treatments ◽

Growing Seasons ◽

Moderate Disease ◽

Untreated Check ◽

Commercial Sugar ◽

Disease Pressure

Curly top, caused by Curtovirus spp., is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. The insecticide seed treatment Poncho Beta has proven to be effective in controlling curly top in sugar beet but was only evaluated under light to moderate disease pressure. Thus, the insecticide seed treatments Poncho Beta, NipsIt INSIDE, and Cruiser Force were evaluated under severe curly top pressure (six viruliferous beet leafhoppers per plant) in field studies during the 2010 and 2011 growing seasons on two commercial sugar beet cultivars. In addition, the foliar insecticides Movento, Provado, and Scorpion were also evaluated. The seed treatments and Scorpion reduced curly top symptoms by 33 to 41% (P < 0.0001) and increased root yield by 55 to 95% (P < 0.0001), sucrose content by 6.5 to 7.2% (P = 0.0013 to <0.0001), and estimated recoverable sucrose by 58 to 96% (P < 0.0001) when compared with the untreated check. Movento and Provado did not improve control beyond that provided by Poncho Beta. Even under severe disease pressure 50 to 55 days after planting, neonicotinoid seed treatments can effectively reduce curly top, increase yield, and help protect against early-season insect pest pressure.

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Interaction of Rhizoctonia solani and Rhizopus stolonifer Causing Root Rot of Sugar Beet

Plant Disease ◽

10.1094/pdis-94-5-0504 ◽

2010 ◽

Vol 94 (5) ◽

pp. 504-509 ◽

Cited By ~ 8

Author(s):

L. E. Hanson

Keyword(s):

Sugar Beet ◽

Root Rot ◽

Management Practices ◽

The United States ◽

Disease Diagnosis ◽

Rhizopus Stolonifer ◽

Rhizoctonia Root Rot ◽

Crown And Root Rot ◽

Growing Conditions ◽

Production Areas

In recent years, growers in Michigan and other sugar beet (Beta vulgaris) production areas of the United States have reported increasing incidence of root rot with little or no crown or foliar symptoms in sugar beet with Rhizoctonia crown and root rot. In addition, Rhizoctonia-resistant beets have been reported with higher levels of disease than expected. In examining beets with Rhizoctonia root rot in Michigan, over 50% of sampled roots had a second potential root rot pathogen, Rhizopus stolonifer. Growing conditions generally were not conducive to disease production by this pathogen alone, so we investigated the potential for interaction between these two pathogens. In greenhouse tests, four of five sugar beet varieties had more severe root rot symptoms when inoculated with both pathogens than when inoculated with either pathogen alone. This synergism occurred under conditions that were not conducive to disease production by R. stolonifer. Host resistance to Rhizoctonia crown and root rot reduced diseases severity, but was insufficient to control the disease when both pathogens were present. This raises concerns about correct disease diagnosis and management practices and indicates that a root rot complex may be important on sugar beet in Michigan.

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Relationship of binucleate Rhizoctonia isolates used for biocontrol of rhizoctonia crown rot of sugar beet to anastomosis systems

Canadian Journal of Microbiology ◽

10.1139/m91-055 ◽

1991 ◽

Vol 37 (5) ◽

pp. 339-344 ◽

Cited By ~ 3

Author(s):

Leonard J. Herr

Keyword(s):

Sugar Beet ◽

Root Rot ◽

Anastomosis Group ◽

The Other ◽

Crown Rot ◽

Considerable Heterogeneity ◽

Binucleate Rhizoctonia ◽

Crown And Root Rot ◽

Relationship Of ◽

Intraspecific Group

The relationships of 10 binucleate Rhizoctonia isolates used as biocontrol agents of rhizoctonia crown and root rot of sugar beet in Ohio to described binucleate Rhizoctonia anastomosis systems were investigated. Ten Ohio binucleate Rhizoctonia (Ohio BNR) isolates, paired in all combinations, cross anastomosed with one another, indicating that all belong to the same anastomosis group. Four representative Ohio BNR isolates failed to anastomose with any tester isolates of the Ceratobasidium anastomosis grouping system, indicating that none belong in that system. However, all 10 Ohio BNR isolates anastomosed with an AG-B (o) tester isolate (binucleate Rhizoctonia anastomosis grouping system), indicating that the Ohio agents belong in this anastomosis grouping system and to the (o) intraspecific group of AG-B. None of the Ohio BNR isolates anastomosed with either of the other two intraspecific group tester isolates (AG-Ba, AG-Bb) of the AG-B group. Moreover, the AG-B intraspecific group tester isolates, AG-Ba, AG-Bb, AG-B (o), self-anastomosed but did not cross anastomose with one another. Variations in cultural characteristics noted among the 10 Ohio BNR isolates indicated that considerable heterogeneity exists within these AG-B (o) isolates. Key words: binucleate Rhizoctonia, anastomosis, rhizoctonia crown rot, sugar beet.

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Influence of selected Rhizoctonia solani isolates on sugar beet seedlings

Journal of Plant Protection Research ◽

10.1515/jppr-2016-0018 ◽

2016 ◽

Vol 56 (2) ◽

pp. 116-121

Author(s):

Paweł Skonieczek ◽

Mirosław Nowakowski ◽

Jacek Piszczek ◽

Marcin Żurek ◽

Łukasz Matyka

Keyword(s):

Sugar Beet ◽

Rhizoctonia Solani ◽

Root Rot ◽

Laboratory Tests ◽

Anastomosis Group ◽

Damping Off ◽

Highly Pathogenic ◽

Breeding Lines ◽

Brown Root Rot

Abstract From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG), which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.

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Influence of Harvest Timing, Fungicides, and Beet necrotic yellow vein virus on Sugar Beet Storage

Plant Disease ◽

10.1094/pdis-10-14-0998-re ◽

2015 ◽

Vol 99 (10) ◽

pp. 1296-1309 ◽

Cited By ~ 6

Author(s):

Carl A. Strausbaugh ◽

Oliver Neher ◽

Eugene Rearick ◽

Imad A. Eujayl

Keyword(s):

Sugar Beet ◽

Root Rot ◽

Fungal Growth ◽

Control Treatment ◽

Water Control ◽

Root Rots ◽

Commercial Sugar ◽

Phoma Betae ◽

Penicillium Spp ◽

Sucrose Loss

Root rots in sugar beet storage can lead to multimillion dollar losses because of reduced sucrose recovery. Thus, studies were conducted to establish additional fungicide treatments for sugar beet storage and a greater understanding of the fungi involved in the sugar beet storage rot complex in Idaho. A water control treatment and three fungicides (Mertect [product at 0.065 ml/kg of roots; 42.3% thiabendazole {vol/vol}], Propulse [product at 0.049 ml/kg of roots; 17.4% fluopyram and 17.4% prothioconazole {vol/vol}], and Stadium [product at 0.13 ml/kg of roots; 12.51% azoxystrobin, 12.51% fludioxonil, and 9.76% difenoconozole {vol/vol}]) were investigated for the ability to control fungal rots of sugar beet roots held up to 148 days in storage during the 2012 and 2013 storage seasons. At the end of September into October, roots were harvested weekly for 5 weeks from each of two sugar beet fields in Idaho, treated with the appropriate fungicide, and placed on top of a commercial indoor sugar beet storage pile until early February. Differences (P < 0.0001 to 0.0150) among fungicide treatments were evident. Propulse- and Stadium-treated roots had 84 to 100% less fungal growth versus the control roots, whereas fungal growth on Mertect-treated roots was not different from the control roots in 7 of 12 comparisons for roots harvested each of the first 3 weeks in both years of this study. The Propulse- and Stadium-treated roots also reduced (P < 0.0001 to 0.0146; based on weeks 1, 3, and 4 in 2012 and weeks 1, 3, 4, and 5 in 2013) sucrose loss by 14 to 46% versus the control roots, whereas roots treated with Mertect did not change sucrose loss compared with the control roots in 7 of 10 evaluations. The predominant fungi isolated from symptomatic roots were an Athelia-like sp., Botrytis cinerea, Penicillium spp., and Phoma betae. If Propulse and Stadium are labeled for use on sugar beet in storage, these fungicides should be considered for root rot control in commercial sugar beet storage and on roots held for vernalization for seed production of this biennial plant species.

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Identification of Rhizoctonia solani isolates from sugar beet roots by analyzing the ITS region of ribosomal DNA

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn0713161s ◽

2007 ◽

pp. 161-171 ◽

Cited By ~ 1

Author(s):

Vera Stojsin ◽

Dragana Budakov ◽

Barry Jacobsen ◽

Eva Grimme ◽

Ferenc Bagi ◽

...

Keyword(s):

Sugar Beet ◽

Rhizoctonia Solani ◽

Ribosomal Dna ◽

Root Rot ◽

Its Region ◽

Anastomosis Group ◽

Crown Rot ◽

Internal Transcribed Spacer Region ◽

The Usa ◽

Crown And Root Rot

Rhizoctonia solani (K?hn) is one of the most important sugar beet pathogens Rhizoctonia solani anastomosis groups (AGs) 2-2 and 4 are proven to be the most common pathogenic strains on sugar beet. AG 2-2 (intraspecific groups IIIB and IV) can cause root and crown rot while damping-off of seedlings is most frequently attributed to AG 4. Four isolates of R. solani from sugar beet roots showing characteristic crown and root rot symptoms, collected from different localities in Vojvodina Province, were chosen and compared to the well-characterized R. solani isolate R9, AG 2-2 IV, from the USA. All Vojvodinian isolates showed medium level of pathogenicity and were able to cause crown and root rot symptoms on inoculated sugar beet roots. Based on anastomosis reaction, isolates from Vojvodina did not belong to the AG 2-2 group. Sequencing of the ITS (internal transcribed spacer) region of ribosomal DNA was performed on the Vojvodinian isolates from R9 in order to determine their relatedness. Sequence analysis showed that these isolates were different than R9 and were closely related (99-100% sequence homology) to anastomosis group 4, subgroup HG II.

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A Novel Penicillium sp. Causes Rot in Stored Sugar Beet Roots in Idaho

Plant Disease ◽

10.1094/pdis-03-17-0410-re ◽

2017 ◽

Vol 101 (10) ◽

pp. 1781-1787 ◽

Cited By ~ 5

Author(s):

Carl A. Strausbaugh ◽

Frank Dugan

Keyword(s):

Sugar Beet ◽

Rna Polymerase Ii ◽

Root Rot ◽

Internal Transcribed Spacer ◽

Penicillium Species ◽

Storage Study ◽

Sugar Beet Cultivar ◽

Commercial Sugar ◽

Penicillium Spp ◽

A New Species

Penicillium vulpinum along with a number of other fungi can lead to rot of stored sugar beet roots. However, Penicillium isolates associated with necrotic lesions on roots from a recent sugar beet storage study were determined to be different from P. vulpinum and other recognized Penicillium species. Phylogenies based on sequencing of the internal transcribed spacer (ITS)-5.8S, β-tubulin (BenA), and RNA polymerase II second largest subunit (RPB2) DNA regions indicate that these isolates are novel, but most closely related to the following Penicillium spp. in the section Fasiculata: P. aurantiogriseum, P. camemberti, and P. freii. Macro- and micromorphological data also support designating these isolates as a new species for which we propose the name, Penicillium cellarum sp. nov. Inoculation studies with the P. cellarum isolates on roots of the commercial sugar beet cultivar B-7 led to the formation of necrotic lesions 23 to 25 mm in diameter after 86 days in storage. These lesions were similar to those observed on sugar beet roots in commercial storage piles. These data indicate that P. cellarum is a pathogen which can cause root rot in stored sugar beet roots.

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Rhizoctonia cerealis anastomosis group GAG-1, the common pathogen of wheat, barley and sugar beet

Acta Mycologica ◽

10.5586/am.1997.010 ◽

2014 ◽

Vol 32 (1) ◽

pp. 107-117

Author(s):

Helena Furgał-Węgrzycka ◽

Jan Adamiak ◽

Ewa Adamiak

Keyword(s):

Growth Rate ◽

Sugar Beet ◽

Crop Rotation ◽

Root Rot ◽

Anastomosis Group ◽

Sharp Eyespot ◽

Pathogenicity Tests ◽

The Common ◽

Hyphal Diameter ◽

Rhizoctonia Cerealis

Isuluies of Rhizoctonia cerealis anastomosis group GAG-1 were obtained from sharp eyespot lesions on wheat and on barley culms and from diseased sugar beet seedlings. Isolates of R. cerealis were collected from a fields with crop rotation experiments: sugar beet-spring wheat-winter barley. In pathogenicity tests isolates of R. cerealis from sugar beet seedlings and from sharp eyespot lesions on wheat and barley were pathogenic to these crops. Isolates of R. cerealis from sharp eyespot lesions on wheat and barley caused severe damping-ofTof sugar beet. Isolates of R. cerealis from sugar beet seedlings also caused symptoms of sharp eyespot on wheat and barley. None of the wheat and barley isolates of R. cerealis tested caused root-rot on wheat or barley seedlings. Isolates of R. cerealis obtained from diseased plants of wheat, barley and sugar beet were similar in morphology of cultures and anastomosed with GAG-1 tester isolate. The relatinoship between anastomosis. colony characters, growth rate, hyphal diameter and pathogenicity of AG-4. AG-2-2 and AG-5 isolates obtained together with R. cerealis from diseased plants were also investigated.

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Leuconostoc spp. Associated with Root Rot in Sugar Beet and Their Interaction with Rhizoctonia solani

Phytopathology ◽

10.1094/phyto-12-15-0325-r ◽

2016 ◽

Vol 106 (5) ◽

pp. 432-441 ◽

Cited By ~ 8

Author(s):

Carl A. Strausbaugh

Keyword(s):

Sugar Beet ◽

Rhizoctonia Solani ◽

Field Studies ◽

Crown Rot ◽

Combination Treatments ◽

Commercial Sugar ◽

Root And Crown Rot ◽

Relationship Of ◽

The Relationship ◽

Important Disease

Rhizoctonia root and crown rot is an important disease problem in sugar beet caused by Rhizoctonia solani and also shown to be associated with Leuconostoc spp. Initial Leuconostoc studies were conducted with only a few isolates and the relationship of Leuconostoc with R. solani is poorly understood; therefore, a more thorough investigation was conducted. In total, 203 Leuconostoc isolates were collected from recently harvested sugar beet roots in southern Idaho and southeastern Oregon during 2010 and 2012: 88 and 85% Leuconostoc mesenteroides, 6 and 15% L. pseudomesenteroides, 2 and 0% L. kimchi, and 4 and 0% unrecognized Leuconostoc spp., respectively. Based on 16S ribosomal RNA sequencing, haplotype 11 (L. mesenteroides isolates) comprised 68 to 70% of the isolates in both years. In pathogenicity field studies with commercial sugar beet ‘B-7’, all Leuconostoc isolates caused more rot (P < 0.0001; α = 0.05) when combined with R. solani than when inoculated alone in both years. Also, 46 of the 52 combination treatments over the 2 years had significantly more rot (P < 0.0001; α = 0.05) than the fungal check. The data support the conclusion that a synergistic interaction leads to more rot when both Leuconostoc spp. and R. solani are present in sugar beet roots.

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