scholarly journals Streptomyces felleus YJ1: Potential Biocontrol Agents Against the Sclerotinia Stem Rot (Sclerotinia sclerotiorum) of Oilseed Rape

2014 ◽  
Vol 6 (4) ◽  
pp. 91 ◽  
Author(s):  
Guanglong Cheng ◽  
Yun Huang ◽  
Hui Yang ◽  
Fan Liu

In order to explore the biocontrol potential of Streptomyces felleus YJ1 to sclerotinia stem rot of oilseed rape, we evaluated the effects of YJ1 as antagonistic strain on Sclerotinia sclerotiorum, including germination and formation of sclerotia, ascospore germination, mycelial growth and YJ1 colonization ability. We found the fermentation filtrate of YJ1 could inhibit sclerotia and ascospore germination and mycelial growth. In dual culture the inhibition zone diameter of YJ1 against S. sclerotiorum was 11.0 mm, and the inhibition rate reached to 80.26%. The ascospores germination was also significantly inhibited by YJ1 fermentation filtrate. In addition, YJ1 could colonize stably in rhizosphere and roots of rape. Otherwise, in the greenhouse we found the lesion would become smaller and slighter if the inoculated leaves were pretreated with YJ1 fermentation liquid. Therefore, our results strongly suggested that YJ1 was a promising biocontrol agent for control of oilseed rape sclerotinia stem rot.

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1613-1620 ◽  
Author(s):  
Xue-ping Huang ◽  
Jian Luo ◽  
Yu-fei Song ◽  
Bei-xing Li ◽  
Wei Mu ◽  
...  

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.


2011 ◽  
Vol 49 (6) ◽  
pp. 884-889 ◽  
Author(s):  
Hui Li ◽  
Huaibo Li ◽  
Yan Bai ◽  
Jing Wang ◽  
Ming Nie ◽  
...  

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1473-1473 ◽  
Author(s):  
G. T. Tziros ◽  
G. A. Bardas ◽  
J. T. Tsialtas ◽  
G. S. Karaoglanidis

Oilseed rape (Brassica napus L.) was recently introduced into Greece for the production of biofuels. During May of 2007, symptoms typical of stem rot were observed on oilseed rape plants in three commercial fields in the area of Galatades-Pella, Central Macedonia, Greece. Approximately 30% of the plants were affected. Symptoms began as a chlorotic wilt on the foliage and developed into necrosis of basal stems. In the advanced stages of the disease, stems and branches became bleached and eventually died. White, as well as black, mycelium and irregularly shaped sclerotia (2 to 5 mm in diameter) were produced abundantly on and inside the affected stems. To isolate the pathogen, 20 symptomatic 6-month-old plants were collected from each field. Sclerotia were dipped in 70% ethanol, surface sterilized in 1% sodium hypochlorite for 1 min, and rinsed in sterile water. Sclerotia placed on potato dextrose agar (PDA) were incubated in the dark at 25°C for 10 days. Sclerotinia sclerotiorum (Lib.) de Bary was identified on the basis of morphological characteristics (2). To conduct pathogenicity tests, 10 6-week-old oilseed rape plants (cv. Titan) were each inoculated with a 5-mm-diameter colonized PDA disk placed in wounds made in the basal stem with a sterile scalpel. Five control plants were treated similarly except that the agar disk did not contain mycelium. Plants were then covered with a plastic bag to maintain high humidity. After 72 h, the bags were removed and the plants were maintained in a growth chamber at 23 to 25°C with a 12-h photoperiod and 75% relative humidity. Pathogenicity tests were repeated three times. Symptoms identical to those observed in the field developed within 12 days after inoculation; control plants remained healthy. The fungus was reisolated from all inoculated plants, confirming Koch's postulates. S. sclerotiorum has been reported on oilseed rape in Argentina, Australia, Brazil, Canada, the United States, and New Zealand (1). To our knowledge, this is the first report of Sclerotinia stem rot of oilseed rape in Greece. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2008. (2) L. M. Kohn. Phytopathology 69:881, 1979.


2016 ◽  
Vol 8 (1) ◽  
pp. 441-444
Author(s):  
Rakesh Rakesh ◽  
A.S. Rathi ◽  
Anil Kumar ◽  
Hawa Singh

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.


2003 ◽  
Vol 43 (2) ◽  
pp. 163 ◽  
Author(s):  
T. L. Hind ◽  
G. J. Ash ◽  
G. M. Murray

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.


Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Feng Zhou ◽  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Hong You ◽  
Fu-Xing Zhu

Growth and virulence stimulations of sublethal doses of fungicides on plant-pathogenic fungi and oomycetes have been reported and the stimulatory effects are potentially relevant to plant disease management. Sclerotinia sclerotiorum is one of the most devastating and economically important necrotrophic fungal phytopathogens, capable of infecting more than 400 species of plants worldwide. In order to study stimulatory effects of sublethal doses of fungicides on S. sclerotiorum, 55 dimethachlon-sensitive isolates and 3 dimethachlon-resistant isolates of S. sclerotiorum were assayed to determine effects of sublethal doses of dimethachlon on mycelial growth rate on potato dextrose agar (PDA) media and virulence on oilseed rape plants. Results showed that all 3 dimethachlon-resistant isolates and 13 of the 55 sensitive isolates exhibited stimulatory responses to sublethal doses of dimethachlon. Dimethachlon-resistant isolates grew significantly (P < 0.05) faster on PDA media amended with dimethachlon at 0.5 to 4 μg/ml than on fungicide-free PDA media. As for virulence on detached leaves of oilseed rape plants, lesion diameters of dimethachlon-resistant isolates after growth on PDA media amended with dimethachlon at 0.5 to 2 μg/ml were significantly larger (P < 0.05) than the control. The maximum stimulatory effects were 42.40 to 59.80%. In pot experiments, for both dimethachlon-sensitive and -resistant isolates, significant (P < 0.05) virulence stimulations were observed after spraying with dimethachlon at a concentration of 2 μg/ml. After growing on dimethachlon-amended PDA media, H2O2 sensitivity of S. sclerotiorum decreased significantly (P < 0.05) compared with the nonamended PDA control.


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