scholarly journals Cotton Seedling Preemergence Damping-Off Incited by Rhizopus oryzae and Pythium spp. and Its Biological Control with Trichoderma spp.

2002 ◽  
Vol 92 (2) ◽  
pp. 177-180 ◽  
Author(s):  
C. R. Howell
Keyword(s):  
Biological Control ◽  
Wheat Bran ◽  
Seed Treatment ◽  
Rhizopus Oryzae ◽  
Infested Soil ◽  
Damping Off ◽  
Trichoderma Spp ◽  
Cotton Seedling ◽  
Germination Stimulants ◽  
Infested Field

Planting the cotton cv. Sure-Grow 747 in cotton seedling disease plots during the 2001 growing season resulted in high levels of preemergence damping-off among the seedlings. Four cotton pathogens, Pythium aphanidermatum, P. ultimum, an unidentified Pythium sp., and Rhizopus oryzae, were isolated from diseased seed embryos and seedlings. Disease incited by the Pythium spp. could be controlled by seed treatment with Metalaxyl, but disease incited by R. oryzae could not. Seed treatment with Metalaxyl in naturally infested field soil was only partially effective; therefore, symptoms in 47% of the diseased seedlings could be attributed to R. oryzae. Susceptibility to disease appeared to be related to release in the spermosphere, by the germinating seeds, of compounds that stimulate pathogen propagule germination, because exudates from seed of the suscept Sure-Grow 747 and extracts from wheat bran induced pathogen germination and growth, whereas exudates from resistant cv. Stoneville 213 did not. However, even Stoneville 213 became susceptible when infested soil was amended with wheat bran. Seed treatment with preparations of Trichoderma virens parent, mutant, and hybrid strains gave effective biological control of preemergence damping-off. Disease control was attributable to metabolism by the biocontrol agent of pathogen germination stimulants released by the seed, because amendment of pathogen-infested soil with the propagule germination stimulants in wheat bran negated the protective effect of the seed treatment.

scholarly journals Effect of Seed Quality and Combination Fungicide-Trichoderma spp. Seed Treatments on Pre- and Postemergence Damping-Off in Cotton

2007 ◽  
Vol 97 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Charles R. Howell
Keyword(s):  
Rhizoctonia Solani ◽  
Seed Treatment ◽  
Seed Quality ◽  
Rhizopus Oryzae ◽  
Poor Quality ◽  
Infested Soil ◽  
Damping Off ◽  
Seed Treatments ◽  
Trichoderma Spp ◽  
Seedling Disease

Good quality seeds of cotton cultivars often escaped pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae, and they were resistant to postemergence damping-off incited by Rhizoctonia solani. Poor quality seeds, however, were highly susceptible to both phases of seedling disease and required seed treatment in order to survive. Pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae could be controlled by seed treatment with biocontrol preparations of a number of Trichoderma spp., but these treatments were much less effective in controlling postemergence disease incited by Rhizoctonia solani. Postemergence seedling disease can be controlled by fungicides, but they were much less effective in controlling the pre-emergence phase of the disease. Combination seed treatments of poor quality cotton seeds with fungicides and Trichoderma spp. preparations, followed by planting in pathogen-infested soil, indicated that this technique will control both phases of seedling disease. Seed treatment with either the fungicides or the biocontrol agents alone did not achieve this goal. The optimum combination treatment for disease control was that of chloroneb plus Trichoderma spp., followed by chloroneb plus metalaxyl (Deltacoat AD) plus T. virens strain G-6.

Biological control of damping-off of sugar-beet and cotton with Chaetomium globosum or a fluorescent Pseudomonas sp.

1988 ◽  
Vol 34 (5) ◽  
pp. 631-637 ◽  
Author(s):  
D. Walther ◽  
D. Gindrat
Keyword(s):  
Biological Control ◽  
Sugar Beet ◽  
Seed Treatment ◽  
Pythium Ultimum ◽  
Chaetomium Globosum ◽  
Pseudomonas Sp ◽  
Damping Off ◽  
Antifungal Metabolites ◽  
Fluorescent Pseudomonas

Seed treatment with ascospores of Chaetomium globosum reduced damping-off of sugar-beet caused by seed-borne Phoma betae and soil-borne Pythium ultimum or Rhizoctonia solani in growth chamber experiments. Seed treatment with a fluorescent Pseudomonas sp. controlled Ph. betae and P. ultimum but not R. solani. Coating cotton seeds with ascospores controlled P. ultimum and R. solani damping-off. In some experiments, biological seed treatments were equally or more effective than seed treatment with captan. However, greater variability in disease control occurred with the antagonists than with captan. Fifty percent of freshly harvested ascospores of C. globosum germinated in 8 h on water agar. When ascospores were stored under air-dried conditions for 3 days to 2.5 years, germination increased to > 90%. Under same storage conditions, survival of Pseudomonas sp. was detected after 4 months. Antagonistic activities observed in vitro were hyphal coiling of C. globosum on R. solani, and mycostasis was induced by C. globosum or Pseudomonas sp. on agar and soil. The presumed cause of mycostasis is the diffusible antifungal metabolites which may also be involved in the biological control of damping-off.

scholarly journals Control of Cotton Seedling Damping-off in the Field by Burkholderia (Pseudomonas) cepacia

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 291-293 ◽  
Author(s):  
K. Zaki ◽  
I. J. Misaghi ◽  
A. Heydari ◽  
M. N. Shatla
Keyword(s):  
Bacillus Subtilis ◽  
Seed Treatment ◽  
Field Trials ◽  
The Other ◽  
Peat Moss ◽  
Pseudomonas Cepacia ◽  
Damping Off ◽  
Cotton Seedling ◽  
Soil Drench

Four field trials were conducted in April 1995 and 1996 in Arizona to compare the effectiveness of: 1, a soil drench of isolate D1 of Burkholderia (Pseudomonas) cepacia; 2, isolate D1 barley meal formulation; 3, Deny seed treatment (a peat moss-based formulation of B. cepacia); 4, Deny soil drench; 5, Kodiak seed treatment (a formulation of Bacillus subtilis); 6, a mixture of three fungicides (metalaxyl, triadimenol, and thiram) seed treatment; and 7, a mixture of metalaxyl, triadimenol, thiram, and Kodiak seed treatment to increase cotton stand in the field. Except for D1, the other products are being marketed for the control of cotton seedling damping-off. Only D1 soil drench and a mixture of the three fungicides seed treatment increased cotton stand significantly (P ≤ 0.05) in three of four field trials.

scholarly journals Seed Treatment Using Pre-infiltration and Biocontrol Agents to Reduce Damping-off of Corn Caused by Species of Pythium and Fusarium

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 294-299 ◽  
Author(s):  
W. Mao ◽  
R. D. Lumsden ◽  
J. A. Lewis ◽  
P. K. Hebbar
Keyword(s):  
Disease Control ◽  
Plant Height ◽  
Root Rot ◽  
Seed Treatment ◽  
Pythium Ultimum ◽  
Biocontrol Agents ◽  
Infested Soil ◽  
Damping Off ◽  
Fresh Weight ◽  
Inoculum Rate

Bioassays were conducted in a greenhouse at 18°C to determine the effectiveness of a seed treatment used in combination with biocontrol agents for the reduction of corn damping-off caused by species of Pythium and Fusarium. Corn seeds were infiltrated with tap water, drained, air-dried, and then coated with biomass of an antagonistic fungus, Gliocladium virens isolate Gl-3, or an antagonistic bacterium, Burkholderia cepacia isolates Bc-B or Bc-1, or a combination of Gl-3 with each of the bacterial isolates. A nonsterile field soil was infested with a combination of pathogens: Pythium ultimum, P. arrhenomanes, and Fusarium graminearum at 2 inoculum rates (1× and 4×). Pre-infiltration enhanced (P ≤ 0.05) disease control with most treatments at both inoculum rates. Treatments with biocontrol agents alone or in combination, as well as the fungicide captan, effectively reduced the disease at a pathogen inoculum rate of 1×, resulting in greater (P ≤ 0.05) seedling stands, plant height, and fresh weight, and lower (P ≤ 0.05) root rot severity compared with untreated seeds in infested soil. At a pathogen inoculum rate of 4×, stands were lower (P ≤ 0.01) and root-rot severity was higher (P ≤ 0.01) compared to those at 1× for all treatments. Nevertheless, coating seeds with all biocontrol agents (alone or in combination), except with Bc-1 alone, reduced disease (P ≤ 0.05) compared to untreated seeds in infested soil. At both inoculum rates of 1× and 4×, coating seeds with Gl-3 + Bc-B was more effective (P ≤ 0.05) in disease control than any other treatment, resulting in stands, growth rate (plant height and fresh weight), and root rot severity similar to plants from untreated seeds in noninfested soil. In addition, when the exudate from a 2-h infiltration of corn seed was added to the seeds during seed coating, seedling stand was often lower and root rot severity was often higher than those from infiltrated seeds (P ≤ 0.05). These results indicated that the infiltration process removed certain exudates, including nutrients and/or stimulants (not detected in this study) that might be utilized by pathogens to initiate seed infection. A thin-layer chromatography (TLC) profile of the exudates showed the presence of eight amino acids and three major carbohydrates.

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 Seed Treatment with Ethanol Extract of Serratia marcescens is Compatible with Trichoderma Isolates for Control of Damping-off of Cucumber Caused by Pythium ultimum

Plant Disease ◽  
2016 ◽  
Vol 100 (7) ◽  
pp. 1278-1287 ◽  
Author(s):  
Daniel P. Roberts ◽  
Dilip K. Lakshman ◽  
Laurie F. McKenna ◽  
Sarah E. Emche ◽  
Jude E. Maul ◽  
...  
Keyword(s):  
Biological Control ◽  
Disease Control ◽  
Seed Treatment ◽  
Sandy Loam ◽  
Ethanol Extract ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Integrated Disease Control ◽  
Loam Soil ◽  
Trichoderma Isolates

Environmentally friendly control measures for soilborne plant pathogens are needed that are effective in different soils when applied alone or as components of an integrated disease control strategy. An ethanol extract of Serratia marcescens N4-5, when applied as a cucumber seed treatment, effectively suppressed damping-off caused by Pythium ultimum in potting mix and in a sandy loam soil. Plant stand associated with this treatment was similar to that of seed treated with the chemical pesticide Thiram in the sandy loam soil. The N4-5 ethanol extract did not consistently provide significant disease control in a loam soil. The N4-5 ethanol extract was compatible with two Trichoderma isolates, not affecting in vitro or in situ colonization of cucumber by these biological control fungi. Control of damping-off of cucumber was never diminished when this ethanol extract was applied as a seed treatment in combination with in-furrow application of the Trichoderma isolates, and disease control was improved in certain instances with these combinations in the loam soil. Data presented here indicate that the N4-5 ethanol extract is compatible with certain beneficial fungi, suggesting that this extract can be used as a component of integrated disease control strategies featuring biological control fungi.

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