Effect of Sclerotinia Stem Rot on Yield of Soybean Inoculated at Different Growth Stages

Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 297-300 ◽  
Author(s):  
G. A. Danielson ◽  
B. D. Nelson ◽  
T. C. Helms
Keyword(s):  
Seed Weight ◽  
Oil Content ◽  
Field Experiments ◽  
Seed Protein ◽  
Disease Incidence ◽  
Stem Rot ◽  
Growth Stages ◽  
Diseased Plant ◽  
Sclerotinia Stem Rot ◽  
Effect On Yield

The effects of Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, on yield of soybean were evaluated in the field with two cultivars in maturity group 0. Plants were inoculated at two growth stages, R3 and R5, using two inoculation methods. Seed weight, seed and pod numbers, seed protein, and oil content were measured. The effects of disease on yield were variable. Disease resulted in significant seed weight loss, with reductions per diseased plant ranging from 18.8 to 38.6%. The estimated yield loss per 10% disease incidence ranged from 83.2 to 229.0 kg/ha, with an average loss of 136.6 kg/ha for four field experiments. A reduction in the number of seeds and pods per plant and seed oil content occurred in some, but not all, experiments. Seed protein was not affected. When disease reduced seed weight, seed and pod numbers, or oil content, there was no growth stage × treatment interaction in the experiments, indicating that inoculation at R5 compared with R3 had a similar effect on yield.

scholarly journals Suppression of Sclerotinia Stem Rot of Soybean by Lactofen Herbicide Treatment

1999 ◽  
Vol 89 (7) ◽  
pp. 598-602 ◽  
Author(s):  
E. K. Dann ◽  
B. W. Diers ◽  
R. Hammerschmidt
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Lesion Size ◽  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
High Disease Severity ◽  
Disease Pressure ◽  
Seed Yields ◽  
Field Plots

Severity of Sclerotinia stem rot of soybean after treatment with lactofen (Cobra) and other herbicides was assessed in field experiments conducted in Michigan from 1995 to 1997. At sites where disease pressure was high, disease severity was reduced 40 to 60% compared with controls when lactofen was applied at the V3 (1995 and 1996) or R1 (1997) growth stages. Corresponding seed yields were unchanged or up to 20% greater when lactofen was applied at the R1 stage in 1997. Disease severity was not reduced by lactofen treatments in years and at sites where disease pressure was low to medium, and corresponding yields often were reduced by ≈10%. High levels of glyceollin accumulated in lactofen-injured leaves collected from field plots in 1996 and 1997. High glyceollin content in lactofen-treated leaves was associated with significant reductions in lesion size when leaves were challenge-inoculated with Sclerotinia sclerotiorum.

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.

Soybean cultivar reaction and row width effect on Sclerotinia stem rot

1993 ◽  
Vol 73 (4) ◽  
pp. 1169-1175 ◽  
Author(s):  
R. I. Buzzell ◽  
T. W. Welacky ◽  
T. R. Anderson
Keyword(s):  
Glycine Max ◽  
Disease Incidence ◽  
Field Trials ◽  
Cultivar Differences ◽  
Stem Rot ◽  
Diseased Plant ◽  
Sclerotinia Stem Rot ◽  
Row Width ◽  
Width Effect ◽  
Glycine Max L

The response of soybean (Glycine max (L.) Merr.) cultivars to Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, was assessed in replicated field trials in 1985–1987 and 1990 to obtain information relating to control of the disease. In 1986 and 1987, there were differences (P = 0.01) in disease incidence among 19 indeterminate cultivars. Cultivar differences in disease incidence were partially related to maturity (R2 = 0.67 in 1986; R2 = 0.37 in 1987) with earlier-maturing cultivars having less disease. Cultivars differed (P = 0.01) in the number of sclerotia produced per diseased plant and per square meter in 1986 and 1987. In a test conducted in 1990 there were differences (P = 0.05) in disease incidence among 14 determinate lines. In three tests in 1985–1986, row spacings of 23, 45 and 69 cm had no significant effect on the incidence of white mold in the cultivars Maple Arrow, Evans, S1346 and Corsoy 79. Yield loss from stem rot may be reduced by planting cultivars that are more resistant, earlier maturing and more tolerant to lodging. This practice would also result in fewer sclerotia to serve as primary inoculum in future years. Key words: Glycine max, soybean, Sclerotinia stem rot, cultivar and row width effects

scholarly journals Yield and Seed Quality of Soybean Cultivars Infected with Sclerotinia sclerotiorum

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 826-829 ◽  
Author(s):  
D. D. Hoffman ◽  
G. L. Hartman ◽  
D. S. Mueller ◽  
R. A. Leitz ◽  
C. D. Nickell ◽  
...  
Keyword(s):  
Seed Germination ◽  
Sclerotinia Sclerotiorum ◽  
Seed Weight ◽  
Oil Content ◽  
Seed Quality ◽  
Disease Incidence ◽  
The United States ◽  
Sclerotinia Stem Rot ◽  
Group Iii ◽  
Central Illinois

Sclerotinia stem rot (SSR) is one of the most important diseases of soybean in the United States. Five maturity group III cultivars, Asgrow A3304 STS (A3304), Pioneer Brand 9342 (P9342), Pioneer Brand 9381 (P9381), Probst, and Yale, grown in fields in east-central Illinois, were used to determine the relationship of SSR incidence to yield, 100-seed weight, seed protein and oil content, visual seed quality, and seed germination. In addition, the number of sclerotia in seed samples and the seedborne incidence of Sclerotinia sclerotiorum were determined. For each cultivar, at least 23 two-row plots, 3 m long, that represented a range of SSR incidence from low to high, were used to count the number of plants with and without SSR stem symptoms and were used to estimate yields and evaluate seed quality. Disease incidence ranged from 2 to 45% for Probst, 0 to 65% for P9381, 0 to 68% for P9342, 1 to 93% for Yale, and 0 to 95% for A3304. Regression of yields on SSR incidences for each cultivar was significant (P < 0.05); for every 10% increase in SSR incidence, yields were reduced by 147, 194, 203, 254, and 263 kg/ha for Probst, A3304, P9342, Yale, and P9381, respectively. Disease incidence was negatively correlated (P < 0.05) with seed germination for all cultivars but Probst, and to oil content and seed weight for P9381 and Yale. Disease incidence was positively correlated (P < 0.05) with seed quality for all cultivars and to the number of sclerotia in harvested seeds for P9342, P9381, and Probst. The seedborne incidence of S. sclerotiorum was 0.3, 0.3, 0.3, 0.4 and 0.7% in A3304, P9381, Yale, Probst, and P9342, respectively, and represents a significant potential for further spread of this pathogen and disease.

scholarly journals Soybean Stem Lignin Concentration Relates to Resistance to Sclerotinia sclerotiorum

Plant Disease ◽  
2009 ◽  
Vol 93 (2) ◽  
pp. 149-154 ◽  
Author(s):  
A. J. Peltier ◽  
R. D. Hatfield ◽  
C. R. Grau
Keyword(s):  
Disease Resistance ◽  
Sclerotinia Sclerotiorum ◽  
Field Experiments ◽  
Lignin Content ◽  
Stem Rot ◽  
Growth Stages ◽  
Soybean Plant ◽  
Sclerotinia Stem Rot ◽  
Lignin Concentration ◽  
Stem Lignin

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is an economically important disease of soybean (Glycine max) in the north-central United States and other temperate regions throughout the world. The occurrence and severity of Sclerotinia stem rot in the field is highly dependent upon prevailing environmental conditions, which can prove problematic when evaluating soybean accessions for resistance. The identification of an environmentally stable plant trait associated with resistance to S. sclerotiorum could be used to indirectly screen for resistance and would prove useful in the identification and development of resistant germplasm. Observations of the soybean–S. sclerotiorum interaction suggest a role for preformed stem lignin content in disease resistance. Although S. sclerotiorum produces numerous enzymes that degrade plant cell wall components, no lignin-degrading enzymes have been reported. Despite a hypothesized direct relationship between preformed lignin content and disease resistance, previous studies on soybean have correlated lignin content to nutritional value and not to disease resistance. We hypothesized that plants with low stem lignin are more susceptible and exhibit greater Sclerotinia stem rot severity than plants with high lignin concentrations. Six soybean accessions that varied in response to S. sclerotiorum were selected for study in a series of field experiments. Soybean stems were sampled at reproductive developmental stages that correspond to specific events in both soybean plant development and the Sclerotinia stem rot disease cycle. The lignin concentration of stem component samples was quantified. Soybean accessions expressed statistically different disease phenotypes in both 2004 and 2006. Lignin concentrations differed among accessions, growth stages, and plant parts. Results were contrary to our hypothesis, with positively ranked correlations observed between accession Sclerotinia stem rot severity and lignin concentration for all nodes and internodes assayed. For the R3 growth stage, lignin concentration of the internode between the fourth and fifth trifoliate leaves correlated best with disease severity data from each year (P = 0.005). These results indicate that resistance is related to low stem lignin concentration and that soybean stem lignin concentration can be used as a biological marker to select for resistance to S. sclerotiorum.

Spread of Sclerotinia stem rot of soybean from area and point sources of apothecial inoculum

2000 ◽  
Vol 80 (2) ◽  
pp. 389-402 ◽  
Author(s):  
S. N. Wegulo ◽  
P. Sun ◽  
C. A. Martinson ◽  
X. B. Yang
Keyword(s):  
Power Law ◽  
Field Experiments ◽  
Disease Incidence ◽  
Exponential Model ◽  
Point Sources ◽  
Stem Rot ◽  
Power Law Model ◽  
Sclerotinia Stem Rot ◽  
Soybean Field ◽  
Area Source

Field experiments were conducted from 1995 to 1998 to quantify the spread of ascospores of Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot of soybean. Incidence of Sclerotinia stem rot measured in a soybean field adjacent to a corn field naturally infested with S. sclerotiorum (area source) was highest close to the area source and decreased with distance from the area source. Disease gradients in the soybean field were described nearly equally well by the exponential model, power law model, and logit-log model. Disease incidence in transects in non-infested areas of a soybean field increased with distance from the edges of soybean and corn area sources of inoculum, reached a maximum at 10–12 and 18–20 m, respectively, from the edges of the inoculum area sources, then decreased in a manner characteristic of the disease gradient curve between 10–12 and 32 m, and 18–20 and 44 m from the edges of the area sources. In soybean plots, disease incidence decreased with distance from point sources of apothecial inoculum. The results from these studies suggest 1) the potential for field to field dispersal of S. sclerotiorum, and 2) that the majority of ascospores of S. sclerotiorum are deposited close to the source (apothecia). Where a concentrated area or point source of S. sclerotiorum inoculum exists, the general exponential model may provide good fits to Sclerotinia stem rot gradient data. Key words: Apothecial inoculum, disease gradients, logit-log model, power law model, simple exponential model

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.

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

Application of thiophanate-methyl at different host growth stages for management of sclerotinia stem rot in soybean

2004 ◽  
Vol 23 (10) ◽  
pp. 983-988 ◽  
Author(s):  
D.S. Mueller ◽  
C.A. Bradley ◽  
C.R. Grau ◽  
J.M. Gaska ◽  
J.E. Kurle ◽  
...  
Keyword(s):  
Stem Rot ◽  
Growth Stages ◽  
Sclerotinia Stem Rot ◽  
Thiophanate Methyl ◽  
Host Growth
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