scholarly journals In vitro Biofumigation of Brassica Tissues Against Potato Stem Rot Caused by Sclerotinia sclerotiorum

2012 ◽  
Vol 28 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Mohammad Reza Ojaghian ◽  
Heng Jiang ◽  
Guan-Lin Xie ◽  
Zhou-Qi Cui ◽  
Jingze Zhang ◽  
...  
Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 969-975 ◽  
Author(s):  
Congying Xu ◽  
Xiaoyu Liang ◽  
Yiping Hou ◽  
Mingguo Zhou

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.


2004 ◽  
Vol 94 (7) ◽  
pp. 737-742 ◽  
Author(s):  
Z. K. Atallah ◽  
B. Larget ◽  
X. Chen ◽  
D. A. Johnson

Sclerotinia sclerotiorum, the causal agent of potato stem rot, is prevalent and poorly managed on potatoes in the Columbia Basin of Washington. Because of the ubiquitous nature of the fungus and high crop diversity within the Columbia Basin, understanding the population structure and the potential for outcrossing of the pathogen would be helpful in developing disease management strategies. The population structure of S. sclerotiorum in the Columbia Basin from potato was examined using microsatellite markers and mycelial compatibility. Analysis of molecular variance revealed that 92% of the variability among 167 isolates was found within subpopulations, with limited, yet statistically significant impact of the collection date, but not the year or location of collection. Linkage disequilibrium and index of association analyses noted a potential for outcrossing in two locations, which was substantiated by the discovery of recombinant ascospores in three field-generated apothecia from the 12 apothecia examined. Microsatellite haplotypes were not correlated with mycelial compatibility groups. This high haplotypic diversity did not seem to impact pathologically important phenotypes. Greenhouse inoculations of potato plants exhibited no significant differences in aggressiveness on potato stems. Moreover, in vitro studies of response to fungicides and temperature stimuli yielded no significant differences among studied isolates. These findings illustrate the potential for outcrossing in warm temperate regions of North America, where a diversity of crops are planted simultaneously and in neighboring fields. This study also indicates that the unsatisfactory management of potato stem rot is likely not directly attributable to genetic factors, but to gaps in agricultural practices.


2013 ◽  
Vol 42 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Leszek B. Orlikowski ◽  
Alma Valjuskate

<em>Phytophthora cinnamomi</em> was isolated from rotted root and stem parts of lavender as well as from soil taken from containers with diseased plants. Additionally <em>Botrytis cinerea, Fusarium</em> spp. and <em>Sclerotinia sclerotiorum</em> were often isolated from diseased tissues. <em>P. cinnamomi</em> colonised leaves and stem parts of 4 lavender species in laboratory trials and caused stem rot of plants in greenhouse experiments. Cardinal temperature for <em>in vitro</em> growth were about 7,5 and 32°C with optimum 25-27,5°C. The species colonised stem tissues at temperature ranged from 10° to 32°C.


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 ◽  
...  

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%.


Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 344-353 ◽  
Author(s):  
J. F. Willbur ◽  
S. Ding ◽  
M. E. Marks ◽  
H. Lucas ◽  
C. R. Grau ◽  
...  

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.


2018 ◽  
Vol 3 (02) ◽  
pp. 171-175
Author(s):  
Devesh Pathak ◽  
R. U. Khan

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.


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.


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