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 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 First Report of Sclerotinia Stem Rot of Chickpea Caused by Sclerotinia sclerotiorum in North Dakota and Washington

Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 114-114 ◽  
Author(s):  
W. Chen ◽  
B. Schatz ◽  
B. Henson ◽  
K. E. McPhee ◽  
F. J. Muehlbauer
Keyword(s):  
North Dakota ◽  
Sclerotinia Sclerotiorum ◽  
Disease Incidence ◽  
Ascochyta Blight ◽  
Growing Season ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Stem Breakage

Chickpea (Cicer arietinum L.) is cultivated as a rotational crop in the cereal-based production system in the U.S. Pacific Northwest (PNW) and its production is expanding to other northern tier states. During July 2005, symptoms of Sclerotinia stem rot were observed on chickpea cv. Dwelley and Dylan in fields near Spangle, WA and Carrington, ND, respectively, with disease incidence of approximately ≤1% in affected areas at both locations. Symptoms included stem whitening, wilting, and stem breakage. Occasionally, white fluffy mycelium was observed; however, production of sclerotia on infected plants was rarely observed. Sclerotinia sclerotiorum was isolated from diseased stems collected from both states. The isolates produced a ring of sclerotia near the edge of potato dextrose agar (PDA) plates in 7 days and produced neither conidia nor other fruiting bodies in culture after 30 days. PCR amplification of the rDNA internal transcribed spacer region from two representative isolates and subsequent digestion with restriction enzymes, Mbo I and Taq I, produced identical banding patterns to previously identified isolates of S. sclerotiorum from pea from the PNW (2). Chickpea cvs. Dwelley and Spanish White (eight plants of each) were inoculated by fastening mycelial agar plugs from an actively growing colony on PDA onto the stems with Parafilm. Symptoms of stem whitening were observed as early as 2 days after inoculation, and the lesions extended upward and downward from the inoculation site. Wilting and stem breakage were also observed. Control inoculations of four plants of each cultivar with PDA plugs without mycelium produced no visible symptoms. S. sclerotiorum was consistently reisolated from inoculated plants but not from control plants. Chickpea had been grown in the PNW for more than 20 years without any reported incidence of Sclerotinia stem rot although the disease has been reported from Arizona (3) and Asian countries (1). This is likely because of the upright growth habit of the chickpea plant coupled with relatively dry conditions late in the growing season. Previous chickpea cultivars were very susceptible to Ascochyta blight, an early-season disease of chickpea in the PNW that reduced chickpea stands and canopy coverage. Current cultivars possess much improved resistance to Ascochyta blight, allowing greater vegetative growth to occur and creating microenvironmental conditions conducive to Sclerotinia stem rot. In North Dakota, where humid conditions prevail late in the growing season, symptoms of Sclerotinia stem rot had been observed in previous years but had not been documented because of a recent history of chickpea cultivation there. To our knowledge, this is the first report of confirmed Sclerotinia stem rot of chickpea in North Dakota and Washington. References: (1) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (2) I. Jimenez-Hidalgo et al. Phytopathology (Abstr.) 94(suppl.):S47, 2004. (3) M. E. Matheron and M. Porchas. Plant Dis. 84:1250, 2000.

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 Silicon Alleviates the Disease Severity of Sclerotinia Stem Rot in Rapeseed

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuxia Feng ◽  
Yuxin Hu ◽  
Pengpeng Fang ◽  
Xiangjun Zuo ◽  
Jinxiong Wang ◽  
...  
Keyword(s):  
Disease Severity ◽  
Seed Quality ◽  
Agronomic Traits ◽  
Induced Defense ◽  
Disease Incidence ◽  
Defense Responses ◽  
Lesion Size ◽  
Stem Rot ◽  
Lesion Length ◽  
Sclerotinia Stem Rot

Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, is a devastating disease in rapeseed. The objective of this study was to investigate the role and the mechanism of silicon (Si) in alleviating the disease severity of S. sclerotiorum in rapeseed. In the absorption assays, the rapeseed that absorbed 10 mM of K2SiO3 exhibited an 86% decrease in lesion size on infected leaves as compared with controls. In the spray assay, the lesion length on rapeseed stems was reduced by 30.5–32.9% with the use of 100 mM of a foliar Si fertilizer as compared with controls. In the pot assay, the lesion length on rapeseed stems was reduced by 34.9–38.3% when using the Si fertilizer as basal fertilizer. In the field assay, both the disease incidence and disease index of sclerotinia stem rot were significantly reduced with the usage of a solid Si fertilizer, Si foliar fertilizer, and the application of both, without negative affection on the main agronomic traits and seed quality of rapeseed. The transcriptome sequencing, quantitative reverse transcription PCR (qRT-PCR), and biochemical assays between K2SO4- and K2SiO3- treated rapeseed leaves revealed that Si promoted the biosynthesis of defense-related substances and enhanced the antioxidation and detoxification abilities of rapeseed after infection. Thus, this study concluded that Si can alleviate the disease severity of S. sclerotiorum in rapeseeds, partially due to the induced defense responses.

scholarly journals First Report of Sclerotinia Stem Rot and Death of Osteospermum spp. Hybrid Cultivars Caused by Sclerotinia sclerotiorum in Louisiana

Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 911-911 ◽  
Author(s):  
G. E. Holcomb
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Disease Incidence ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Greenhouse Production ◽  
First Report ◽  
Similar Disease ◽  
Plastic Bag ◽  
Pathogenicity Tests ◽  
Stem Lesions

Osteospermum spp. Hybrids, belong to Asteraceae, commonly called African daisy or cape daisy with over 214 named cultivars, are popular flowering plants grown as winter landscape plants in southern Louisiana. During January of 2005, plants growing in a wholesale nursery using polyethylene-film-covered greenhouses were observed with symptoms of wilt that began with tan stem lesions and progressed to stem rot, wilt, and plant death. Plants had been purchased out-of-state as rooted cuttings and transplanted to a commercial bark potting mix in 11.4-cm (4.5-in.) plastic pots. Signs of fungal infection included the presence of white cottony mycelium and black sclerotia. Disease incidence was 50% on cv. Soprano White but less than 1% among the four other cultivars being grown (Ostica Blue Eye, Ostica Pink, Lemon Symphony, and Soprano Purple). Differences in disease incidence among cultivars may have been due to differences in susceptibility since all were grown on the same greenhouse bench. Sclerotinia sclerotiorum was consistently isolated from sections of diseased stems that had been surfaced disinfested (30 to 60 s in 70% ethyl alcohol) and placed on acidified potato dextrose agar. Inoculum for pathogenicity tests consisted of mixed mycelia and sclerotia that had been grown on twice-sterilized wheat grain for 14 days. Ten flowering-age Osteospermum sp. plants of cv. Soprano White were inoculated with 1 g of inoculum placed at the base of each plant. One group of five plants was kept in a dew chamber at 22°C for 40 h after which they were removed to a greenhouse. The second group of five plants was placed in a single, plastic bag with the top left open and kept in the greenhouse. Ten noninoculated plants of the same cultivar served as controls with five kept in the dew chamber for 40 h and the other five held in a plastic bag in the greenhouse. Inoculated plants that had been held in the dew chamber developed stem lesions and rot after 2 days, wilted permanently after 5 days, and were desiccated and dead by day 7. Inoculated plants held in the bag in the greenhouse followed a similar disease development pattern but did not show wilt symptoms until 8 days after inoculation and were dead after 12 days. White cottony mycelium and black sclerotia developed on stems and at the base of all inoculated plants. S. sclerotiorum was reisolated from inoculated diseased plants. All noninoculated control plants remained disease free. An outbreak of this disease was previously reported on Osteospermum spp. planted along highways in southern California (1). To our knowledge, this is the first report of the disease in Louisiana and the first report of its occurrence in greenhouse production of Osteospermum spp. Reference: (1) H. S. Gill. Plant Dis. Rep. 59:82, 1975

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.

Prevalence of sclerotinia stem rot of canola in New South Wales

2003 ◽  
Vol 43 (2) ◽  
pp. 163 ◽  
Author(s):  
T. L. Hind ◽  
G. J. Ash ◽  
G. M. Murray
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
New South ◽  
New South Wales ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Mean Values ◽  
Stem Infection ◽  
South Wales

Surveys of petal infestation and stem infection conducted in 1998, 1999 and 2000 indicated that Sclerotinia sclerotiorum poses a threat to the Australian canola industry. Inoculum was present throughout all canola-growing regions of New South Wales and the stem disease was widespread throughout southern New South Wales. Percentage petal infestation increased over the 3 years surveyed with values ranging from 0 to 99.4%. The highest petal infestation values were observed in 2000 (maximum of 99.4%, mean of 82.2%), with lower mean values in 1998 (38.4%) and 1999 (49.6%). Stem infection ranged from 0 to 37.5% and most fields had less than 10% stem infection. Stem rot incidence before harvest did not relate to percentage petal infestation determined during flowering. This indicated that factors other than percentage petal infestation were important in influencing stem rot incidence. While there was no relationship between percentage petal infestation and stem rot incidence, stem infection never occurred without prior petal infestation.

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