Activity of Tolclofos - Methyl (Rizolex) on Sclerotium rolfsii and Rhizoctonia solani in Peanut1

1985 ◽  
Vol 12 (1) ◽  
pp. 32-35 ◽  
Author(s):  
A. S. Csinos

Abstract Tolclofos-methyl was compared to PCNB in vitro to determine its relative activity against four isolates of Sclerotium rolfsii Sacc. and two isolates of Rhizoctonia solani Kuehn. Concentrations of 0.001, 0.01, 0.1, 1.0 and 10 μg/mL of each of the fungicides were used to evaluate their effects on radial growth on both S. rolfsii and R. solani and their effects on sclerotia formation and sclerotial germination of S. rolfsii. Little difference in efficacy between the fungicides occurred for S. rolfsii. However, tolclofos-methyl reduced radial growth of R. solani more than PCNB at concentrations of 0.1 and 1.0 μg/mL. In field tests in 1982 and 1984 tolclofos-methyl at 5.6 kg ai/ha or less was as effective or superior to PCNB or PCNB-fensulfothion in reducing incidence of southern stem rot and increasing yield. In 1984, tolclofos-methyl at 8.4 kg ai/ha reduced Rhizotonia limb rot damage over the control, but PCNB at 11.2 kg ai/ha did not.

1990 ◽  
Vol 17 (1) ◽  
pp. 28-31 ◽  
Author(s):  
T. B. Brenneman ◽  
A. S. Csinos ◽  
P. M. Phipps

Abstract Ammonium bicarbonate was evaluated for efficacy against southern stem rot and Sclerotinia blight of peanut in Georgia and Virginia, respectively. In vitro studies indicated the material provided little inhibition of mycelial growth by Sclerotinia minor and Sclerotium rolfsii, and negligible inhibition of mycelial growth of Rhizoctonia solani AG-4. However, ammonium bicarbonate did effectively inhibit formation of sclerotia by S. rolfsii in vitro. In the field, it was phytotoxic when applied as a granule or as a foliar spray and in general was not effective in controlling disease or increasing pod yield.


1987 ◽  
Vol 14 (2) ◽  
pp. 55-58 ◽  
Author(s):  
A. S. Csinos

Abstract Flutolanil (SN 84364) was evaluated in vitro against Sclerotium rolfsii and Rhizoctonia solani AG-4. ED50 values were < 0.01 and < 0.1 μg/mL for S. rolfsii and R. solani, respectively, while Pentachloronitrobenzene (PCNB) had ED50 values of < 0.1 and < 1.0 μg/mL, respectively. Concentrations of flutolanil at 0.1 μg/mL greatly reduced sclerotia and sclerotia initial development of S. rolfsii. Field evaluations were conducted near Tifton, GA, during 1983–86 for control of southern stem rot (S. rolfsii) and Rhizoctonia limb rot (R. solani AG 4) on peanut (Arachis hypogaea L.). Flutolanil 50 WP applied as a banded (40 cm) foliar spray at rates of 1.12 – 5.6 kg ai/ha at pegging (about 60 days post seeding) significantly (P = 0.05) decreased both disease loci numbers caused by S. rolfsii and percentage of vines infected with R. solani. Yields were increased significantly (P = 0.05) in all treatments over the four years of trials. Flutolanil 7 G was significantly (P = 0.05) less effective in controlling southern stem rot and increasing yield than the 50 WP formulation.


2015 ◽  
Vol 9 (6) ◽  
pp. 365-372 ◽  
Author(s):  
J Parmar H ◽  
P Bodar N ◽  
N Lakhani H ◽  
V Patel S ◽  
V Umrania V ◽  
...  

2002 ◽  
Vol 127 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Stephanie G. Harvey ◽  
Heather N. Hannahan ◽  
Carl E. Sams

Allyl isothiocyanate (AITC) is the predominant isothiocyanate produced by damaged tissues of Indian mustard (Brassica juncea (L) Czerniak). This study investigated Indian mustard and AITC mediated suppression of mycelial growth and sclerotial germination of Sclerotium rolfsii Saccardo, a common soilborne pathogen. Indian mustard (IM) treatments of 0, 0.1, 0.2, 0.6, 1.0, 2.0, 4.1, 5.1, 10.2, 20.4, 40.8, 81.6, and 163.3 g·L-1 (weight of reconstituted mustard per liter of air) were evaluated for suppression of mycelial growth. Treatment effect was evaluated by measuring the radial growth of mycelia. Sclerotia were placed in culture tubes containing 18 g autoclaved soil and covered with an additional 5 g soil. AITC at concentrations of 0, 4.0, 16.0, 64.0, 256.0, 1024.0, or 4096.0 μmol·L-1 was injected into the tubes. Treated sclerotia were removed from tubes and plated on potato dextrose agar to determine viability. Mycelial growth was inhibited with IM treatments (P < 0.01). Inhibiting concentrations (IC) of IM for mycelial growth inhibition of 50% and 90% were 0.7 and 1.0 g·L-1, respectively, with death resulting with >2 g·L-1. Inhibition attributable to AITC alone was lower than that achieved by IM producing equivalent amounts of AITC. Germination of sclerotia was negatively correlated with AITC concentration (r = 0.96; P < 0.01). The IC50 and IC90, of AITC were 249.0 and 528.8 μmol·L-1, respectively, at 42 hours. The lethal concentration for sclerotia was not reached; only suppression occurred at the highest treatment concentrations. Sclerotium rolfsii mycelia were sensitive to the IM volatiles and were suppressed at low concentrations. Sclerotia were more resistant than the mycelia and required higher concentrations of AITC to suppress germination.


1990 ◽  
Vol 17 (2) ◽  
pp. 65-67 ◽  
Author(s):  
T. B. Brenneman ◽  
W. D. Branch ◽  
A. S. Csinos

Abstract The susceptibility of 16 peanut (Arachis hypogaea L.) genotypes (eight Virginia and eight runner types) to southern stem rot (Sclerotium rolfsii Sacc.) was evaluated in field tests over three years. Mean disease incidence for all cultivars was 10.0, 15.4 and 16.4 disease loci per 12.2 m row and average yields were 3488, 2826 and 3569 kg/ha in 1986, 1987 and 1988, respectively. Disease incidence averaged 14.3 disease loci per 12.2 m of row for both market types. The mean yield for the eight Virginia types was 3287 kg/ha versus 3214 for the eight runner types. Culitvars within market types varied significantly in disease incidence and pod yield. Of the Virginia types, NC 6 and Florigiant were the most susceptible with NC 9, VA 81B and Early Bunch being the most resistant. Incidence of stem rot in runner cultivars was high except for Southern Runner and Langley which had about 50% less disease than the most susceptible entries. There was a highly significant correlation (P≤0.01) between yields and disease incidence all three years. Overall, Southern Runner had the lowest disease incidence and highest pod yield of any cultivar. Compared to Florunner, the current industry standard for runner types, Southern Runner had about 50% less disease and yields were 1346 kg/ha higher.


2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 620-622
Author(s):  
M. Porras ◽  
C. Barrau ◽  
B. Santos ◽  
F.T. Arroyo ◽  
C. Blanco ◽  
...  

Effect of temperature on growth and antagonistic ability of Trichoderma spp. isolated from local strawberry culture and commercial product, against Rhizoctonia solani, strawberry pathogen, was studied in vitro. Trials were carried out twice, at 10, 25 and 30°C. Inhibitor effect was evaluated by radial growth measures of established duals on PDA’s dishes, using Royse and Ries formula, to evaluate the percentage inhibition of radial growth. Design of dishes was a randomized complete block, considering 10 replicates. Data were analyzed statistically by two-way analysis of variance. The objective has been to determine the most competitive Trichoderma strain and the best temperature that produce the inhibiting effect on the pathogen growth. Local strain has the best behavior at 10 and 25°C.


1969 ◽  
Vol 71 (2) ◽  
pp. 165-176
Author(s):  
Lydia I. Rivera-Vargas ◽  
Paul R. Hepperly

Laboratory and production bed observations reveal that the major fungal competitors of the Chinese straw mushroom growing on sugarcane bagasse are Sclerotium rolfsii Sacc., Corticium sp., Coprinus sp., Aspergillus flavus Link ex Fries and Chaetomium globosum Kunze ex Steud. Because of their perceived importance, these five fungi were selected for control studies. The selectivity of fungicides for the control of these fungi in Chinese straw mushroom beds was tested in vitro. Benomyl, captan, carboxin, chloroneb, mancozeb and penthachloronitrobenzene (PCNB) were tested in poison agar tests at the rates of 1, 10 and 100 p/m a.i. with Chinese straw mushroom and the selective competitors. Mushroom radial growth was reduced in all treatments of carboxin and at 10 and 100 p/m of chloroneb. Compared to these, PCNB was intermediately toxic. Chinese straw mushroom was tolerant to all concentrations of benomyl, captan and mancozeb. A. flavus radial growth was highly reduced with benomyl and slightly reduced by carboxin, chloroneb and PCNB. S. rolfsii showed growth reduction at 10 and 100 p/m of PCNB, chloroneb and carboxin. Growth of Coprinus sp., Corticium sp., C. globosum and A. flavus was reduced over 90% with treatments of benomyl at 100 p/m. Fungicidal sprays were evaluated in vivo on sugarcane bagasse and coffee pulp beds. Poor pasteurization of the coffee pulp was associated with rampant development of Aspergillus fumigatus Fries. and Mucor sp. Partial superficial control of these fungi was obtained with mancozeb alone (50 to 75% reduction of visible growth). Benomyl alone and in combination with mancozeb gave excellent suppression of fungi on the mushroom beds (90% reduction of visible growth). None of the treatments controlled fungi within the beds.


1997 ◽  
Vol 24 (1) ◽  
pp. 17-19 ◽  
Author(s):  
M-Y. Shim ◽  
J. L. Starr

Abstract The effect of soil pH on sclerotial germination and pathogenicity of two isolates of Sclerotium rolfsii on peanut was examined. Sclerotial germination for both isolates was greater (P ≤ 0.05) in acidic soil than at alkaline pHs. Similarly, percentage of peanut stems infected by S. rolfsii in greenhouse tests was greater at soil pH 5.6 than at alkaline soil pHs (P ≤ 0.05), but disease did develop at soil pH 8.7 and 9.8. In contrast to a previous in vitro study, these data confirm that sclerotia of S. rolfsii will germinate and initiate disease at soil pH &gt; 7.0.


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.


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