scholarly journals Greenhouse Evaluation of Seed and Drench Treatments for Organic Management of Soilborne Pathogens of Spinach

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1281-1292 ◽  
Author(s):  
Jaime A. Cummings ◽  
Carol A. Miles ◽  
Lindsey J. du Toit
Keyword(s):  
Seed Treatment ◽  
Pythium Ultimum ◽  
Organic Production ◽  
Compost Tea ◽  
Damping Off ◽  
Seed Treatments ◽  
Greenhouse Study ◽  
Greenhouse Evaluation ◽  
Equivalent Control ◽  
Bacillus Pumilis

The efficacy of 14 seed and drench treatments for control of soilborne damping-off pathogens in organic production of spinach was evaluated in a greenhouse study. The efficacy of each treatment was compared with nontreated seed and seed treated with a conventional fungicide for control of Fusarium oxysporum f. sp. spinaciae, Pythium ultimum, and Rhizoctonia solani. Two experimental seed treatments, GTG I and GTG II (each comprised of a proprietary organic disinfectant and the latter also containing Trichoderma harzianum T22), provided equivalent control to the conventional fungicide, mefenoxam, against P. ultimum in one trial and significant reduction of damping-off in the second trial. Natural II and Natural X (Streptomycete products), and Subtilex (Bacillus subtilis) seed treatments each suppressed damping-off significantly in one of the two trials. For R. solani, GTG I and Natural II seed treatments reduced damping-off as effectively as a drench with the fungicide Terraclor (pentachloronitrobenzene). A soil drench with Prestop (Gliocladium catenulatum) suppressed postemergence wilt caused by F. oxysporum in both trials; a compost tea drench and seed treatment with Yield Shield (Bacillus pumilis) each suppressed postemergence wilt in only one of two trials. GTG I and GTG II significantly increased seed germination compared to nontreated seed. No treatment was effective against all three pathogens, and some treatments exacerbated damping-off.

scholarly journals Evaluation of Microbial, Botanical, and Organic Treatments for Control of Peanut Seedling Diseases

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 445-454 ◽  
Author(s):  
S. J. Ruark ◽  
B. B. Shew
Keyword(s):  
Cover Crops ◽  
Seed Treatment ◽  
Soil Amendments ◽  
Organic Production ◽  
Hot Water ◽  
Natural Soil ◽  
Damping Off ◽  
Seed Treatments ◽  
Coniothyrium Minitans ◽  
Untreated Seed

Diseases affecting stand establishment are a major obstacle to organic production of peanut (Arachis hypogaea). Stand losses of 50% or more are possible with untreated seed. Biological, botanical, and organic seed treatments or soil amendments were tested for efficacy against pre- and postemergence damping-off of peanut in greenhouse, microplot, and field plot trials. Seed of the lines Perry, GP-NC 343, and Bailey (tested as N03081T) were used in all trials. Commercial formulations of Bacillus subtilis (Kodiak), B. pumilus (Yield Shield), Trichoderma harzianum (T-22 PB and Plantshield HC), Muscodor albus, and Coniothyrium minitans (Contans); activated charcoal; two separate soil amendments of dried herbage of Monarda didyma cultivars; a commercial fungicide control (Vitavax PC); and an untreated control were tested in natural soil in the greenhouse. Vitavax PC and Kodiak were the only treatments that resulted in higher percent emergence and survival than in untreated seed. A separate greenhouse experiment was conducted in natural soil or natural soil infested with field isolates of Aspergillus niger. Seed were treated with Kodiak, copper hydroxide (Champion), Plantshield HC, Kodiak + Plantshield HC, Streptomyces griseoviridis (Mycostop), hot water, Vitavax PC, or were left untreated. Seedling emergence and survival was much lower in infested versus uninfested soil. Seed treatment with Kodiak increased percent emergence and survival compared to untreated seed, but was not as effective as Vitavax PC. Field microplot studies in 2007 and 2008 at Clayton, NC, evaluated four seed treatments on the peanut lines following small grain cover crops, soil amendment with M. albus, or no cover. Cover crops did not affect emergence or interact with seed treatments. In field studies in 2007 and 2008 at Lewiston, NC, the peanut lines were planted with M. albus infurrow, with Kodiak or T. harzianum seed treatments, or were untreated. In the 2007 trial, none of the treatments improved stands compared to the untreated check. In 2008, the highest stand counts were produced by seed treated with Kodiak. In both years, Bailey produced the greatest stand counts. A. niger was strongly associated with postemergence damping-off in the field. Regardless of peanut line, in many trials, Kodiak seed treatment increased emergence and survival over untreated seed.

scholarly journals The Efficacy of Ethaboxam as a Soybean Seed Treatment Toward Phytophthora, Phytopythium, and Pythium in Ohio

Plant Disease ◽  
2020 ◽  
Vol 104 (5) ◽  
pp. 1421-1432 ◽  
Author(s):  
Kelsey Scott ◽  
Meredith Eyre ◽  
Dair McDuffee ◽  
Anne E. Dorrance
Keyword(s):  
Seed Treatment ◽  
Soybean Seed ◽  
Primary Objective ◽  
Phytophthora Species ◽  
Damping Off ◽  
Seed Treatments ◽  
Seedling Disease ◽  
Seed Decay ◽  
Fungicide Mixtures ◽  
Seed Rot

Phytophthora, Phytopythium, and Pythium species that cause early-season seed decay and pre-emergence and post-emergence damping off of soybean are most commonly managed with seed treatments. The phenylamide fungicides metalaxyl and mefenoxam, and ethaboxam are effective toward some but not all species. The primary objective of this study was to evaluate the efficacy of ethaboxam in fungicide mixtures and compare those with other fungicides as seed treatments to protect soybean against Pythium, Phytopythium, and Phytophthora species in both high-disease field environments and laboratory seed plate assays. The second objective was to evaluate these seed treatment mixtures on cultivars that have varying levels and combinations of resistance to these soilborne pathogens. Five of eight environments received adequate precipitation in the 14 days after planting for high levels of seedling disease development and treatment evaluations. Three environments had significantly greater stands, and three had significantly greater yield when ethaboxam was used in the seed treatment mixture compared with treatments containing metalaxyl or mefenoxam alone. Three fungicide formulations significantly reduced disease severity compared with nontreated in the seed plate assay for 17 species. However, the combination of ethaboxam plus metalaxyl in a mixture was more effective than either fungicide alone against some Pythium and Phytopythium species. Overall, our results indicate that the addition of ethaboxam to a fungicide seed treatment is effective in reducing seed rot caused by these pathogens commonly isolated from soybean in Ohio but that these effects can be masked when cultivars with resistance are planted.

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 FIELD PERFORMANCE OF BIO-PRIMING FOR PROTECTION OF sh2 SWEET CORN FROM PREEMERGENCE DAMPING-OFF CAUSED BY PYTHIUM ULTIMUM.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1110f-1110
Author(s):  
Nancy W. Callan ◽  
James B. Miller ◽  
Don E. Mathre
Keyword(s):  
Pseudomonas Fluorescens ◽  
Seed Treatment ◽  
Field Experiments ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Field Performance ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Corn Seed ◽  
Seed Bacterization

Shrunken-2 supersweet (sh2) sweet corn is susceptible to preemergence damping-off caused by Pythium ultimum, especially when planted into cold soil. Bio-priming, a seed treatment which combines the establishment of a bioprotectant on the seed with preplant seed hydration, was developed to protect seeds from damping-off.In a series of field experiments conducted in Montana's Bitterroot and Gallatin Valleys, bio-priming or seed bacterization with Pseudomonas fluorescens AB254 protected sweet corn from P. ultimum damping-off. Bio-priming corn seed with P. fluorescens AB254 was comparable to treatment with the fungicide metalaxyl in increasing seedling emergence. Seedlings from bio-primed seeds emerged from the soil more rapidly than from nontreated seeds and were larger at three weeks postplanting. Seeds of sh 2 and sugary enhancer (se) sweet corn, as well as that of several sh 2 cultivars, were protected from damping-off by bio-priming.

scholarly journals Beneficial Effects of Solid Matrix Chemo-priming in Okra

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 535-537 ◽  
Author(s):  
K. E. Conway ◽  
R. Mereddy ◽  
B. A. Kahn ◽  
Y. Wu ◽  
S. W. Hallgren ◽  
...  
Keyword(s):  
Untreated Control ◽  
Seed Treatment ◽  
Seedling Emergence ◽  
Pythium Ultimum ◽  
Field Trials ◽  
Solid Matrix ◽  
Damping Off ◽  
Untreated Seed ◽  
Beneficial Effects ◽  
Emergence And Reduction

Two field trials at Stillwater and Bixby, OK, evaluated the efficacy of solid matrix priming techniques, alone or in combination with fungicide seed treatment on seedling emergence and reduction of damping-off of okra in field soil naturally infested with Pythium ultimum. The following treatments were evaluated: thiram + carboxin (chemo-primed) (commercially applied), biological seed treatment (bio-primed) (Trichoderma harzianum isolate OK-110, 1 g suspended in 1% carboxymethylcellulose [CMC]), untreated seed (control), and a 1% CMC control. Chemo-primed seeds had a more uniform and faster emergence compared with untreated seeds at both field sites. Within 3 days, 92 and 78% of chemo-primed seeds had emerged at Stillwater and Bixby, respectively, compared with 84 and 71% emergence in the untreated control. Mean emergence of chemo-primed seeds was lower (P ≤ 0.05) than the untreated control. Chemo-primed seeds had greater vigor (P≤ 0.05) at both locations compared with either fungicide-treated or priming alone, at both locations. There were no differences (P ≤ 0.05) in yield among treatments at both locations. P. ultimum was consistently isolated from damped-off seedlings and surrounding soil at both locations. Isolates of P. ultimum were more pathogenic on okra in laboratory tests than isolates of Rhizoctonia spp., Fusarium spp., and other Pythium spp. also isolated from seed or soil.

scholarly journals Infection of Soybean Seed by Fusarium graminearum and Effect of Seed Treatments on Disease Under Controlled Conditions

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 401-407 ◽  
Author(s):  
M. L. Ellis ◽  
K. D. Broders ◽  
P. A. Paul ◽  
A. E. Dorrance
Keyword(s):  
Fusarium Graminearum ◽  
Seed Treatment ◽  
Soybean Seed ◽  
Disease Development ◽  
Damping Off ◽  
Optimum Conditions ◽  
Seed Treatments ◽  
Seedling Disease ◽  
Seed Decay ◽  
Recent Emergence

Fusarium graminearum causes seed decay and damping-off of soybean. This study evaluated the effect of inoculum density of F. graminearum, temperature, and fungicide seed treatments on disease development. To determine the optimum conditions for disease development, individual soybean seed was inoculated with 100 μl of a suspension of 2.5 × 102, 2.5 × 103, 2.5 × 104, or 2.5 × 105 macroconidia/ml in a rolled-towel assay at temperatures of 18, 22, and 25°C. Inoculum concentrations of 2.5 × 104 macroconidia/ml or higher were necessary for optimum disease development at all temperatures. The efficacy of captan, fludioxonil, mefenoxam + fludioxonil, azoxystrobin, trifloxystrobin, and pyraclostrobin as seed treatments was then evaluated with the same assay at 2.5 × 104 and 2.5 × 105 macroconidia/ml. Seed treated with captan at 61.9 g a.i. or fludioxonil at 2.5 or 5.0 g a.i. per 100 kg developed smaller lesions than other seed treatments and the nontreated control. Based on these results, there are limited choices in fungicide seed treatments for managing this seedling disease, and it is possible that shifts in seed treatment products may have played a role in the recent emergence of this soybean pathogen.

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 Field Performance of Sweet Corn Seed Bio-primed and Coated with Pseudomonas fluorescens AB254

HortScience ◽  
1991 ◽  
Vol 26 (9) ◽  
pp. 1163-1165 ◽  
Author(s):  
Nancy W. Callan ◽  
Don E. Mathre ◽  
James B. Miller
Keyword(s):  
Pseudomonas Fluorescens ◽  
Seed Treatment ◽  
Field Experiments ◽  
Sweet Corn ◽  
Field Performance ◽  
Pythium Ultimum ◽  
Seedling Height ◽  
Damping Off ◽  
Corn Seed ◽  
Degree Of Protection

In field experiments, bio-priming and coating with Pseudomonas fluorescens AB254 consistently protected sweet corn (Zea mays L.) seeds from preemergence damping-off caused by Pythium ultimum Trow. The bio-priming seed treatment was evaluated under various disease pressures and with seeds of three sweet corn genotypes: shrunken-2 supersweet (sh-2), sugary enhancer (se), and sugary (su). While no damping-off occurred in the su sweet corn, bio-priming protected sh-2 and se sweet corn seeds at a level equivalent to that obtained by treatment with the fungicide metalaxyl. Biopriming increased seedling height of all three sweet corn genotypes at 4 weeks post-planting. Coating of sweet corn seeds with P. fluorescens AB254 provided an equivalent degree of protection from damping-off under all but the most severe conditions.

scholarly journals Biological Seed Treatments

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 749E-749
Author(s):  
Nancy W. Callan ◽  
Don E. Mathre
Keyword(s):  
Seed Treatment ◽  
Sweet Corn ◽  
Seed Priming ◽  
Pythium Ultimum ◽  
Nutrient Level ◽  
Seed Treatments ◽  
Seed Decay ◽  
Environmentally Responsible ◽  
And Function ◽  
Disease Pressure

Biological seed treatment offers a safe, environmentally responsible option for protection of seeds and seedlings from attack by soilborne pathogens. Most effective biological seed treatments have used either bacterial or fungal agents. The efficacy of a biological seed treatment depends upon the ability of the biocontrol agent to compete and function on the seed and in the rhizosphere under diverse conditions of soil pH, nutrient level, moisture, temperature, and disease pressure. Seed treatment performance may be improved through application and formulation technology. An example of this is the bio-priming seed treatment, a combination of seed priming and inoculation with Pseudomonas aureofaciens AB254, which was originally developed for protection of sh-2 sweet corn from Pythium ultimum seed decay. Bio-priming has been evaluated for protection of seed of sweet corn and other crops under a range of soil environmental conditions.

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