scholarly journals Efficacy of Fungicides on Sclerotinia sclerotiorum and Their Potential for Control of Sclerotinia Stem Rot on Soybean

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 26-31 ◽  
Author(s):  
D. S. Mueller ◽  
A. E. Dorrance ◽  
R. C. Derksen ◽  
E. Ozkan ◽  
J. E. Kurle ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Radial Growth ◽  
Disease Incidence ◽  
Leaf Tissue ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Thiophanate Methyl ◽  
Application Systems

Sclerotinia stem rot of soybean, caused by Sclerotinia sclerotiorum, is a major disease in the north central region of the United States. One approach to managing Sclerotinia stem rot on soybean is the use of fungicides. S. sclerotiorum was assayed for sensitivity to benomyl, tebuconazole, thiophanate methyl, and vinclozolin in pure cultures on agar medium, inoculated soybean seedlings, detached inoculated leaves, and in experimental field plots. To evaluate the inhibitory effect of four fungicides on growth of S. sclerotiorum in vitro, potato dextrose agar (PDA) was amended with the fungicides at six concentrations. Based on measurements of fungal radial growth, vinclozolin was the most effective in inhibiting S. sclerotiorum mycelial growth at 1.0 μg a.i./ml of PDA. Ranges of reduction of radial growth of 91 isolates of S. sclerotiorum on PDA amended with thiophanate methyl and vinclozolin were 18 to 93% and 93 to 99%, respectively, when compared with the nonamended agar control. Benomyl, thiophanate methyl, and vinclozolin applied to greenhouse-grown seedlings prevented S. sclerotiorum from expressing symptoms or signs on leaf tissue. Detached leaves sprayed with thiophanate methyl and then inoculated with mycelial plugs of S. sclerotiorum did not express symptoms or signs. Of 13 different environments in Illinois, Indiana, Ohio, and Wisconsin from 1995 through 2000, six had low Sclerotinia stem rot incidence (<1%), three environments had low to moderate Sclerotinia stem rot incidence (5 to 25%), and four environments had high Sclerotinia stem rot incidence (>25%). When disease incidence was high, no consistent control of Sclerotinia stem rot was observed with benomyl or thiophanate methyl using different application systems. However, under low disease incidence, spray systems that were able to penetrate the canopy reduced the incidence of Sclerotinia stem rot an average of 50%.

scholarly journals Comprehensive Sclerotinia Stem Rot Screening of Soybean Germplasm Requires Multiple Isolates of Sclerotinia sclerotiorum

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 344-353 ◽  
Author(s):  
J. F. Willbur ◽  
S. Ding ◽  
M. E. Marks ◽  
H. Lucas ◽  
C. R. Grau ◽  
...  
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Resistance Breeding ◽  
The United States ◽  
Stem Rot ◽  
In Vitro Growth ◽  
Sclerotinia Stem Rot ◽  
In Planta ◽  
Soybean Germplasm

Sclerotinia sclerotiorum population variability directly affects Sclerotinia stem rot (SSR) resistance breeding programs. In the north-central United States, however, soybean germplasm selection has often involved only a single isolate. Forty-four S. sclerotiorum isolates from Illinois, Michigan, Minnesota, Nebraska, Wisconsin, Poland, and across 11 different host species were evaluated for variation in isolate in vitro growth, in vitro oxalate production, and in planta aggressiveness on the susceptible soybean ‘Williams 82’. Significant differences (P < 0.0001) were detected in isolate in planta aggressiveness, in vitro growth, and in vitro oxalate production. Furthermore, diverse isolate characteristics were observed within all hosts and locations of collection. Aggressiveness was not correlated to colony growth and was only weakly correlated (r = 0.26, P < 0.0001) to isolate oxalate production. In addition, the host or location of collection did not explain isolate aggressiveness. Isolate oxalic acid production, however, may be partially explained by the host (P < 0.05) and location (P < 0.01) of collection. Using a representative subset of nine S. sclerotiorum isolates and soybean genotypes exhibiting susceptible or resistant responses (determined using a single isolate), a significant interaction (P = 0.04) was detected between isolates and genotypes when SSR severity was evaluated. Our findings suggest that screening of S. sclerotiorum-resistant soybean germplasm should be performed with multiple isolates to account for the overall diversity of S. sclerotiorum isolates found throughout the soybean-growing regions of the United States.

Evaluation of fungicides and bio-control agents in-vitro, against Sclerotinia sclerotiorum causes white stem rot disease in Rapeseed-mustard

2018 ◽  
Vol 3 (02) ◽  
pp. 171-175
Author(s):  
Devesh Pathak ◽  
R. U. Khan
Keyword(s):  
Growth Inhibition ◽  
Sclerotinia Sclerotiorum ◽  
Radial Growth ◽  
Stem Rot ◽  
Yield Losses ◽  
Sclerotinia Stem Rot ◽  
Plant Debris ◽  
Trichoderma Spp ◽  
Rot Disease

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) de Bary is a major disease of rapeseed-mustard and it is considered next to Alternaria blight in causing yield losses as much as 70 per cent in susceptible crop. The pathogen survives in the form of sclerotia on plant debris or in soil for more than 4 years, which makes it very difficult to manage with conventional approaches. Therefore, its management with fungicides and bio-control agents remains an effective approach. The present study was undertaken in-vitro, using four fungicides viz., vitavax, propiconazole, mancozeb and azoxystrobin at three different concentrations i.e. 0.05%, 0.1% and 0.2% and three species of Trichoderma viz., T. harzianum, T. viride, T. koningii,to find out their relative efficacy in inhibiting mycelial growth of the pathogen. It is evident from the observations that all four fungicides and three Trichoderma spp. resulted a significant effect on growth inhibition of S. sclerotiorum. Among all fungicides tested, vitavax and propiconazole were most effective at all three concentrations (0.05, 0.1 and 0.2 %) and inhibited cent percent radial growth of the pathogen, while mancozeb and azoxystrobin were least effective. Among the bio-control agents, T. viride was noted to be most effective antagonist followed by T. koningii resulting 78.50% and 72.21% growth inhibition, respectively. Whereas, T. harzianum showed minimum radial growth inhibition (49.25%) of S. sclerotiorum in this study.

scholarly journals Evaluation of fungicides for the control of Sclerotinia stem rot of Indian mustard caused by Sclerotinia sclerotiorum (Lib.) de Bary

2016 ◽  
Vol 8 (1) ◽  
pp. 441-444
Author(s):  
Rakesh Rakesh ◽  
A.S. Rathi ◽  
Anil Kumar ◽  
Hawa Singh
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Seed Yield ◽  
Untreated Control ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Indian Mustard ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Foliar Sprays

The current investigation was carried out under -in vitro and under sick plot conditions of the Department of Plant Pathology, CCS Haryana Agricultural University, Hisar to test the efficacy of different fungicides against Sclerotinia sclerotiorum. The experiment was carried out through poison food technique under in vitro conditions andthrough foliar sprays under sick plot conditions. Efficacy of fungicides in vitro against S. sclerotiorum showed that carbendazim and hexaconazole completely inhibited mycelial growth up to 100 per cent at 50 ppm concentration. Propiconazole inhibited 96.39 per cent mycelial growth at 50 ppm and 100 per cent at 1000 ppm, while tricyclazole failed to inhibit mycelial growth up to 100 ppm, however, at 1000 ppm concentration, there was 100 per cent mycelial inhibition. Mancozeb and captan completely inhibited up to 100 per cent mycelial growth at 500 ppm concentration. Copper oxychloride and pencycuron were not effective at lower concentrations but had inhibited 45.28 and 22.50 per cent mycelial growth at 1000 ppm. Field experiment was conducted to test the efficacy of those fungicides which were found best under in vitro conditions. All the four fungicides tested significantly controlled Sclerotinia stem rot disease and increased the seed yield as compared to untreated control. Two Foliar sprays with hexaconazole @ 0.05% at 45 and 60 days after sowing was found most effective in controlling disease incidence up to 78.3 per cent and increasing seed yield up to 37.6 per cent as compared to untreated control.

scholarly journals Favorable Bioactivity of the SDHI Fungicide Benzovindiflupyr Against Sclerotinia sclerotiorum Mycelial Growth, Sclerotial Production, and Myceliogenic and Carpogenic Germination of Sclerotia

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1613-1620 ◽  
Author(s):  
Xue-ping Huang ◽  
Jian Luo ◽  
Yu-fei Song ◽  
Bei-xing Li ◽  
Wei Mu ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Baseline Sensitivity ◽  
Carpogenic Germination ◽  
Alternative Product ◽  
Application Potential ◽  
New Generation

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a prevalent plant pathogen. This study aims to evaluate the application potential of benzovindiflupyr, a new generation of succinate dehydrogenase inhibitor (SDHI), against S. sclerotiorum. In our study, 181 isolates collected from different crops (including eggplant [n = 34], cucumber [n = 27], tomato [n = 29], pepper [n = 35], pumpkin [n = 32], and kidney bean [n = 25]) in China were used to establish baseline sensitivity to benzovindiflupyr. The frequency distribution of the 50% effective concentration (EC50) values of benzovindiflupyr was a unimodal curve, with mean EC50 values of 0.0260 ± 0.011 μg/ml, and no significant differences in mean EC50 existed among the various crops (P > 0.99). Benzovindiflupyr can effectively inhibit mycelial growth, sclerotial production, sclerotial shape, and myceliogenic and carpogenic germination of the sclerotia of S. sclerotiorum. In addition, benzovindiflupyr showed good systemic translocation in eggplant. Using benzovindiflupyr at 100 μg/ml yielded efficacies of 71.3 and 80.5% for transverse activity and cross-layer activity, respectively, which were higher than those of acropetal and basipetal treatments (43.6 and 44.7%, respectively). Greenhouse experiments were then carried out at two experimental sites for verification. Applying benzovindiflupyr at 200 g a.i. ha−1 significantly reduced the disease incidence and severity of Sclerotinia stem rot. Overall, the results demonstrated that benzovindiflupyr is a potential alternative product to control Sclerotinia stem rot.

scholarly journals Effects of the Novel Fungicide Benzothiostrobin on Sclerotinia sclerotiorum in the Laboratory and on Sclerotinia Stem Rot in Rape Fields

Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 969-975 ◽  
Author(s):  
Congying Xu ◽  
Xiaoyu Liang ◽  
Yiping Hou ◽  
Mingguo Zhou
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Pathogenic Fungus ◽  
Field Trials ◽  
Stem Rot ◽  
Cross Resistance ◽  
Synergistic Activity ◽  
The Novel ◽  
Sclerotinia Stem Rot ◽  
Sclerotial Germination

We determined the effects and efficacy of benzothiostrobin, a new strobilurin-derived fungicide, against the plant-pathogenic fungus Sclerotinia sclerotiorum (the causal agent of Sclerotinia stem rot). Mycelial growth and sclerotial germination in vitro were strongly inhibited by benzothiostrobin in the presence of salicylhydroxamic acid. On detached rapeseed leaves, benzothiostrobin at 40 μg/ml reduced lesion development by 87%. No cross-resistance was detected between benzothiostrobin and carbendazim, iprodione, fludioxonil, or boscalid. A formulated mixture of benzothiostrobin and fluazinam at 1:1 had synergistic activity against S. sclerotiorum in vitro. In field trials, benzothiostrobin alone or formulated with fluazinam at 1:1 (150 g a.i. ha−1) was significantly (P < 0.05) superior to iprodione in controlling Sclerotinia stem rot of rapeseed. These results suggest that benzothiostrobin has substantial potential for the control of Sclerotinia stem rot.

Evaluation of disease forecasting variables for sclerotinia stem rot (Sclerotinia sclerotiorum) of canola

2000 ◽  
Vol 80 (4) ◽  
pp. 889-898 ◽  
Author(s):  
M. Bom ◽  
G. J. Boland
Keyword(s):  
Soil Moisture ◽  
Disease Severity ◽  
Sclerotinia Sclerotiorum ◽  
Prediction Models ◽  
Disease Incidence ◽  
Stem Rot ◽  
Disease Prediction ◽  
Strong Correlations ◽  
Sclerotinia Stem Rot ◽  
Spring Canola

Selected environmental, crop and pathogen variables were sampled weekly from winter and spring canola crops before and during flowering and evaluated for the ability to predict sclerotinia stem rot, caused by Sclertinia sclerotirum. Linear and nonlinear relationships were examined among variables but, because no strong correlations were observed between final disease incidence and any of the variables tested, a categorical approach (e.g., disease severity) was used instead. Disease severity in individual crops was categorized as low (< 20% diseased plants) or high (> 20% disease), and differences in weekly rainfall, soil moisture, crop height, percentage of petal infestation, and number of apothecia m−2 and clumps of apothecia m−2 were significantly associated with differences in disease severity within or between years. Two disease prediction models were compared for the ability to predict low or high disease severities using petal infestation alone, or petal infestation in combination with soil moisture. The model that included petal infestation and soil moisture predicted more fields correctly than the model using petal infestation alone, but the accuracy of both was affected by the timing of soil moisture measurements in relation to petal infestation, and threshold values used in discriminating categories of soil moisture and petal infestation. Key words: Brassica rapa, Brassica napus, Sclerotinia sclerotiorum, disease prediction

scholarly journals Occurrence of Stem Rot on Canola Caused by Sclerotinia sclerotiorum in Argentina

Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 530-530 ◽  
Author(s):  
S. Gaetán ◽  
M. Madia
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Buenos Aires ◽  
Disease Incidence ◽  
Fungal Growth ◽  
Ground Level ◽  
The United States ◽  
Stem Rot ◽  
Buenos Aires Province ◽  
Rot Disease

Canola (Brassica napus) was introduced as an alternative crop for wheat in Argentina. During 2003, typical symptoms of stem rot disease were observed on canola plants in two commercial fields located at Bragado, in northern Buenos Aires Province in Argentina. Average disease incidence across four canola cultivars was 21% (range = 13 to 29%). Symptoms included chlorosis and wilting of foliage and necrosis of basal stems. The disease appeared singly or in patches consisting of 4- to 5-month-old plants. The first visible symptom noticed was chlorosis and wilting of the foliage beginning from the basal leaves. Infection of the main stem at ground level typically was followed by a grayish white discoloration that progressed above the soil line to the apex. In advanced stages of the disease, stems and branches became bleached and eventually died. Black and irregularly shaped sclerotia (average size 5.5 × 2.8 mm) inside necrotic stem tissue were the typical signs of the pathogen. From September to October 2003, four samples consisting of six affected plants per sample were arbitrarily collected from two commercial fields located at Bragado. Sclerotia were taken from diseased stems, dipped in 70% ethanol, surface sterilized with 1% sodium hypochlorite for 1 min, and rinsed in sterile water. Each sclerotium was blotted dry on sterile Whatman's filter paper and placed on potato dextrose agar. Plates were incubated in the dark at 25°C for 2 to 3 days, followed by incubation under 12-h NUV light/12-h dark for 6 to 8 days. Six resulting colonies were identified as Sclerotinia sclerotiorum (Lib.) de Bary on the basis of taxonomic characteristics of the plant pathogenic species of Sclerotinia (3). Koch's postulates for three fungal isolates from infected plants were carried out on 6-week-old canola plants (cvs. Eclipse, Impulse, Master, and Mistral) by placing a colonized agar disk into wounds made in the basal stem region with a sterile scalpel. Pathogenicity tests, which included five inoculated and three control plants potted in a sterilized soil mix (soil/sand, 3:1), were conducted in a greenhouse at 23 to 26°C and 75% relative humidity with no supplemental light. Characteristic symptoms identical to the original observations developed within 12 days after inoculation on 100% of the inoculated plants for three isolates. Symptoms included wilted foliage, collapsed plants, and plant death. White mycelium and sclerotia developed on infected tissues, and the pathogen was successfully reisolated from symptomatic plants in all instances. Control plants, which were treated similarly except that the agar disk did not contain fungal growth, remained healthy. The experiment was repeated, and the results were identical to the first inoculations. Canola stem rot disease incited by S. sclerotiorum was first reported in Argentina during 1995 at experimental field plots in Buenos Aires. S. sclerotiorum, which has been reported to cause disease in canola in Canada (2) and the United States (1,4), currently represents a serious problem to the main canola cultivars grown in Argentina. To our knowledge, this is the first report of the occurrence of S. sclerotiorum causing a high incidence of stem rot in commercial crops of canola in Argentina. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) L. B. Jamaux et al. Plant Pathol. 44:22, 1995. (3) L. M. Kohn. Phytopathology 69:881, 1979. (4) D. V. Phillips et al. Phytopathology 92:785, 2002.

scholarly journals Soybean Varietal Response and Yield Loss Caused by Sclerotinia sclerotiorum

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 456-461 ◽  
Author(s):  
X. B. Yang ◽  
P. Lundeen ◽  
M. D. Uphoff
Keyword(s):  
Regression Analysis ◽  
Sclerotinia Sclerotiorum ◽  
Disease Incidence ◽  
Pearson Correlation ◽  
The United States ◽  
Yield Losses ◽  
Linear Regression Models ◽  
Sclerotinia Stem Rot ◽  
Varietal Response ◽  
Maturity Groups

Soybean Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, has recently emerged from being a minor problem in areas where soybeans of maturity groups 0 to I are grown to a significant cause of soybean yield losses in the north-central region, which produces 80% of soybean in the United States. Studies were conducted in Iowa to quantify varietal response to S. sclerotiorum for cultivars of maturity groups I to III in fields that had uniform infestation histories. Over the course of the study, disease incidence was generally high at the northern Iowa sites but low in central Iowa, with disease incidence of susceptible standards >60% and <30%, respectively. Regression analysis showed that maturity class significantly affected disease incidence, with greater effects in environments where susceptible standard cultivars had high disease incidences. Consistency of varietal response among the environments was quantified using Pearson correlation analysis. When disease incidence was high, varietal responses measured by disease ratings and yield were consistent among locations, but the responses were inconsistent when disease incidence was low. Pearson correlation coefficients ranged from 0.80 to 0.94 for disease incidence and 0.58 to 0.81 for yield among the experiments having high disease incidence in susceptible standards. The relationship between disease incidence and yield was well described by linear regression models with coefficients of determination (r2) ranging from 0.59 to 0.83. Based on regression slopes (significant at P < 0.0001), yield losses are estimated to range from 170 to 335 kg/ha for each 10 percentage points of disease incidence. Regression analysis also showed that maturity groups had a linear relationship with disease incidence (r2 = 0.18 to 0.39, P < 0.01).

scholarly journals Impact of Sclerotinia Stem Rot on Yield of Canola

Plant Disease ◽  
2007 ◽  
Vol 91 (2) ◽  
pp. 191-194 ◽  
Author(s):  
L. E. del Río ◽  
C. A. Bradley ◽  
R. A. Henson ◽  
G. J. Endres ◽  
B. K. Hanson ◽  
...  
Keyword(s):  
North Dakota ◽  
Field Experiments ◽  
Disease Incidence ◽  
The United States ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Potential Yield ◽  
Naturally Occurring ◽  
The Cost ◽  
The Impact

Sclerotinia sclerotiorum is the causal agent of Sclerotinia stem rot (SSR) of canola (Brassica napus). In North Dakota, the leading canola producer in the United States, SSR is an endemic disease. In order to estimate the impact of this disease on canola yield, field experiments were conducted from 2000 to 2004 at several locations in North Dakota and Minnesota. Experimental plots were either inoculated with laboratory-produced ascospores or infected by naturally occurring inoculum in commercial fields. Applying fungicides at different concentrations and timings during the flowering period created epiphytotics of diverse intensities. Disease incidence was measured once prior to harvesting the crop on 50 to 100 plants per plot. Results of the study indicated that 0.5% of the potential yield (equivalent to 12.75 kg/ha) was lost for every unit percentage of SSR incidence (range of 0.18 to 0.96%). Considering the current cost of fungicide applications and the market value of this commodity, a 17% SSR incidence could cause losses similar to the cost of a fungicide application. Additional efforts are required to improve current levels of tolerance of canola plants to this pathogen.

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