scholarly journals Effect of Potting Mix Microbial Carrying Capacity on Biological Control of Rhizoctonia Damping-Off of Radish and Rhizoctonia Crown and Root Rot of Poinsettia

2001 ◽  
Vol 91 (11) ◽  
pp. 1116-1123 ◽  
Author(s):  
Matthew S. Krause ◽  
Laurence V. Madden ◽  
Harry A. J. Hoitink
Keyword(s):  
Biological Control ◽  
Carrying Capacity ◽  
Root Rot ◽  
Biocontrol Agents ◽  
Pine Bark ◽  
Damping Off ◽  
Indigenous Microorganisms ◽  
Sphagnum Peat ◽  
Trichoderma Hamatum ◽  
Crown And Root Rot

Potting mixes prepared with dark, highly decomposed Sphagnum peat, with light, less decomposed Sphagnum peat, or with composted pine bark, all three of which were colonized by indigenous microorganisms, failed to consistently suppress Rhizoctonia damping-off of radish or Rhizoctonia crown and root rot of poinsettia. Inoculation of these mixes with Chryseobacterium gleum (C299R2) and Trichoderma hamatum 382 (T382) significantly reduced the severity of both diseases in the composted pine bark mix in which both biocontrol agents maintained high populations over 90 days. These microorganisms were less effective against damping-off in the light and dark peat mixes, respectively, in which populations of C299R2 declined. In contrast, crown and root rot, a disease that is severe late in the crop, was suppressed in all three types of mixes. High populations of T382 in all three mixes late during the cropping cycle may have contributed to control of this disease.

scholarly journals Biological control of seedling damping-off and root rot of sugar beet plants

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 645-647 ◽  
Author(s):  
M.K. El-Kazzaz ◽  
M.M. Badr ◽  
H.M. El-Zahaby ◽  
M.I. Gouda
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Natural Infection ◽  
Infested Soil ◽  
Damping Off ◽  
Root Yield ◽  
Trichoderma Hamatum ◽  
Actinomycete Isolate

Some fungal and bacterial bioagents as well as an Actinomycete isolate were screened for their antagonistic effects against S. rolfsii, R. solani, M. phaseolina, F. oxysporum and F. solani in vitro. Trichoderma hamatum, T. harzianum, T. pseudokningii, certain isolates of Bacillus subtilis and one isolate of Pseudomonas fluorescens were the most effective bioagents in suppressing the radial growth of the four pathogens, in general. Yet, they were less effective in retarding growth of Fusarium spp. as compared with the other pathogens under study. Studying biological control showed the possibility of controlling sugar beet damping-off and root rot by certain bioagents as T. hamatum, T. hazianum, Pseudomonas fluorescens and B. subtilis under greenhouse (S. rolfsii-infested soil) and field (natural infection) conditions. These treatments also caused and increase root yield per plot.

scholarly journals Rhizospheric bacteria as potential biocontrol agents against Fusarium wilt and crown and root rot diseases in tomato

2021 ◽  
Author(s):  
Md. Masudur Rahman Khalil ◽  
Rosario Alicia Fierro-Coronado ◽  
Ofelda Peñuelas-Rubio ◽  
Alma Guadalupe Villa-Lerma ◽  
Rigoberto Plascencia-Jatomea ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Root Rot ◽  
Biocontrol Agents ◽  
Rhizospheric Bacteria ◽  
Crown And Root Rot

scholarly journals Sensitivity of Rhizoctonia solani AG-2-2 from Sugar Beet to Fungicides

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Sahar Arabiat ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
The United States ◽  
Damping Off ◽  
Growth Assay ◽  
The Mean ◽  
Crown And Root Rot ◽  
Mean Concentration

Rhizoctonia damping-off and crown and root rot caused by Rhizoctonia solani are major diseases of sugar beet (Beta vulgaris L.) worldwide, and growers in the United States rely on fungicides for disease management. Sensitivity of R. solani to fungicides was evaluated in vitro using a mycelial radial growth assay and by evaluating disease severity on R. solani AG 2-2 inoculated plants treated with fungicides in the greenhouse. The mean concentration that caused 50% mycelial growth inhibition (EC50) values for baseline isolates (collected before the fungicides were registered for sugar beet) were 49.7, 97.1, 0.3, 0.2, and 0.9 μg ml−1 and for nonbaseline isolates (collected after registration and use of fungicides) were 296.1, 341.7, 0.9, 0.2, and 0.6 μg ml−1 for azoxystrobin, trifloxystrobin, pyraclostrobin, penthiopyrad, and prothioconazole, respectively. The mean EC50 values of azoxystrobin, trifloxystrobin, and pyraclostrobin significantly increased in the nonbaseline isolates compared with baseline isolates, with a resistant factor of 6.0, 3.5, and 3.0, respectively. Frequency of isolates with EC50 values >10 μg ml−1 for azoxystrobin and trifloxystrobin increased from 25% in baseline isolates to 80% in nonbaseline isolates. Although sensitivity of nonbaseline isolates of R. solani to quinone outside inhibitors decreased, these fungicides at labeled rates were still effective at controlling the pathogen under greenhouse conditions.

scholarly journals Improvment Biocontrol of Damping-Off and Root Rot/Wilt of Faba Bean by Salicylic Acid and Hydrogen Peroxide

2013 ◽  
Vol 2 (1) ◽  
pp. 14-24
Author(s):  
Montaser F. Abdel-Monaim
Keyword(s):  
Hydrogen Peroxide ◽  
Salicylic Acid ◽  
Faba Bean ◽  
Root Rot ◽  
Yield Components ◽  
Growth Parameters ◽  
Biocontrol Agents ◽  
Damping Off ◽  
Chemical Inducers ◽  
Bean Plants

Rhizoctonia solani, Fusarium solani, F. oxysporum and Macrophomina phaseolina were found to be associated with root rot and wilt symptoms of faba bean plants collected from different fields in New Valley governorate, Egypt. All the obtained isolates were able to attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenicity tests. Biocontrol agents (Trichoderma viride, Bacillus megaterium) and chemical inducers (salicylic acid and hydrogen peroxide) individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promotion of faba bean plants in vitro and in vivo. Both antagonistic biocontrol agents and chemical inducers either individually or in combination inhibited growth of the tested pathogenic fungi.Biocontrol agents combined with chemical inducers recorded the highest inhibited growth especially in case SA + T. viride and SA+ B. megaterium. Under green house and field conditions, all treatments significantly reduced damping-off and root rot/ wilt severity and increased survival of plants. Also, these treatments increased fresh and dry weights of the survived plants in pots compared with control.  The combination of biocontrol agents and chemical inducers were more effective than using them individually and SA+ T. viride was the best treatment in this respect. Under field conditions, all these treatments significantly increased growth parameters (plant height and No. of branches plant-1) and yield components (No. of pods and seedsplant-1, weight of 100 seeds and total yield feddan-1 and protein content in both seasons (2010-2011 and 2011-2012). Faba bean seeds soaked in SA+ T. viride and SA+ B. megaterium were recorded the highest growth parameters and yield components. Generally, the combination of biocontrol agents and chemical inducers recoded the best results for controlling damping-off and root rot/wilt diseases in greenhouse and field with addition improved plant growth and increased yield components in the field. 

scholarly journals Use of Fungicides and Biological Controls in the Suppression of Fusarium Crown and Root Rot of Asparagus Under Greenhouse and Growth Chamber Conditions

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 493-498 ◽  
Author(s):  
T. C. Reid ◽  
M. K. Hausbeck ◽  
K. Kizilkaya
Keyword(s):  
Biological Control ◽  
Root Rot ◽  
Field Experiments ◽  
Growth Chamber ◽  
Root Weight ◽  
Fusarium Spp ◽  
Crown And Root Rot ◽  
Control Disease ◽  
Disease Pressure ◽  
Commercial Field

Growth chamber, greenhouse, and field experiments were conducted with fungicides and biological control agents, including nonpathogenic isolates of Fusarium oxysporum, to test their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies with asparagus seedlings in soil, Trichoderma harzianum strain T-22, benomyl, and fludioxonil treatments increased root weight and decreased root disease compared with the infested control when a low level of F. oxysporum f. sp. asparagi and F. proliferatum was used. The fungicide fludioxonil limited plant death caused by Fusarium spp. at high inoculum levels, whereas T. harzianum strain T-22 was not effective. Nonpathogenic isolates of F. oxysporum were effective in limiting Fusarium disease on asparagus seedlings in culture tubes, although isolates differed in their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies, no significant differences in plant death were found between asparagus plants growing in media infested with F. oxysporum f. sp. asparagi and F. proliferatum and left untreated, and those treated with nonpathogenic F. oxysporum. The efficacy of fungicides and biological control products to control Fusarium crown and root rot under commercial field conditions could not be evaluated due to low disease pressure.

scholarly journals Optimizing Fungicide Timing for the Control of Rhizoctonia Crown and Root Rot of Sugar Beet Using Soil Temperature and Plant Growth Stages

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1091-1098 ◽  
Author(s):  
W. W. Kirk ◽  
P. S. Wharton ◽  
R. L. Schafer ◽  
P. Tumbalam ◽  
S. Poindexter ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Soil Temperature ◽  
Root Rot ◽  
Small Scale ◽  
Damping Off ◽  
Yield Attributes ◽  
Fungicide Application ◽  
Temperature Thresholds ◽  
Large Plot ◽  
Crown And Root Rot

Azoxystrobin is applied early in the sugar beet growing season in north-central United States for control of Rhizoctonia damping-off and Rhizoctonia crown and root rot caused by Rhizoctonia solani anastomoses groups (AGs) 4 and 2-2, respectively. Fungicide application timings based on crop growth stage and soil temperature thresholds were evaluated in inoculated small-scale trials and in commercial fields with a history of Rhizoctonia crown and root rot. Soil temperature thresholds of 10, 15, and 20°C were selected for fungicide application timings and used to test whether soil temperature could be used to better time applications of azoxystrobin. In both small- and large-plot trials, timing applications after attainment of specific soil temperature thresholds did not improve efficacy of azoxystrobin in controlling damping-off or Rhizoctonia crown and root rot compared with application timings based on either planting date, seedling development, or leaf stage in a susceptible (E-17) and a resistant (RH-5) cultivar. Application rate and split application timings of azoxystrobin had no significant effect on severity of crown and root rot. Other environmental factors such as soil moisture may interact with soil temperature to influence disease development. Cv. RH-5 had higher sugar yield attributes than the susceptible cultivar (E-17) in seasons conducive and nonconducive to crown and root rot development. All isolates recovered from both small- and large-plot trials in all years were AG 2-2. R. solani AG 4 was not identified in any samples from any year.

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